Wiper Blades
The windshield wiper system is another area that requires periodic service. The wiper blades are inspected and replaced when they are worn out. The windshield washer fluid reservoir is inspected and refilled when it is low. The technician who performs these services should have a basic understanding of how the system works.
An electric wiper motor, located under the cowl panel, provides the power for the system. When the wiper switch is turned on, the motor begins to move a linkage system back and forth. This motion is transferred to a set of wiper arms on the outside of the windshield. Wiper blades attached to the arms move back and forth across the windshield.
When the windshield needs washing, the driver can turn the wiper switch to activate the washer system. The washer system consists of a reservoir, pump, hose, and washer nozzle. The reservoir contains windshield washer fluid. An electric pump in the reservoir pumps cleaning fluid out of the reservoir through a hose to the washer nozzle. The nozzle is located below the windshield and directs a spray on the windshield. When the washer is activated, the wipers are also activated so the wiper blades move the fluid across the windshield to clean it.
The windshield washer fluid reservoir is a plastic bottle. The reservoir is located under the hood in the engine compartment. The level of washing fluid can be observed through the container. Washer fluid is available in containers from automotive parts stores. Always check the owner's manual for the recommended type of fluid.
The wiper arm is attached to the linkage from the wiper motor. The wiper blade assembly is the part that contacts the windshield. It has a metal support that holds a rubber wiper blade. The support holds the rubber blade in the proper position against the windshield.
Inspect and Refill Windshield Wiper Fluid
The windshield washer system must have enough windshield washer fluid to properly clean the windshield. Anytime you service the windshield wipers or are under the hood, inspect and refill any lost windshield wiper fluid.
Windshield washer fluid is available in automotive parts stores. The fluid is often colored blue so that it is easy to see in the washer system reservoir.
Open the hood and locate the washer reservoir Typically, the reservoir is transparent so the fluid can be seen through the reservoir. Inspect the fluid level. Some reservoirs have a "full" line, but most are filled all the way to the top. If the level is low, remove the cap on top. Place a clean funnel in the cap opening and pour in the washer fluid until it reaches the correct level.
WARNING: You will need to add windshield washer antifreeze to prevent the washer fluid from freezing in cold weather conditions.
WARNING: Never use dirty fluid or a dirty funnel in a washer system. Dirt in the system can clog the tiny jets that spray the fluid on the windshield.
Remove and Replace a Windshield Wiper Blade
The rubber wiper part of a windshield wiper blade deteriorates from contact with sun and smog. It wears from contact with the windshield. Worn windshield wiper blades will not properly wipe the windshield. They could create a safety hazard for a driver in bad weather. A wiper blade can get so worn that the rubber part separates from the metal part. The metal part could then scratch the windshield when the wipers are turned on. Consequently, the wipers should be inspected regularly and replaced as necessary.
Worn wiper blades may be replaced in two ways. You can buy an entire wiper blade assembly or just a rubber insert . The insert is less expensive and a good choice for a newer car. The wiper assembly is a good choice on an older car in which the metal wiper parts are corroded or damaged.
To replace either the blade assembly or just an insert, remove the blade assembly from the wiper arm. There are many types of retaining systems used between the arm and blade. The most common is the release lever. You release the arm from the blade by lifting up on the tiny release lever.
Often the insert is held with spring clips called bridge claws or lock tabs. A button may have to be pushed to disengage some types. You will have to squeeze or pinch other parts to release the lock tabs.
Be careful not to lose the small parts during disassembly and reassembly. Always compare the replacement parts with the new ones. When you have installed the new blade assemblies or inserts, test the system. First clean all dirt or dust from the windshield. Pour water on the glass and turn on the wipers. Check to see that they do a good job wiping the water.
WARNING: Never operate wipers on a dry or dirty windshield. The blades could rub the dirt over the windshield and cause scratches.
SERVICE TIP: Never disassemble both wiper assemblies at the same time. Do one at a time and use the assembled unit as a guide for correct assembly.
Question:
How often should I replace my wiper blades?
Answer:
Wiper blades are one of the most neglected components on vehicles today. Many blades are cracked, split, torn, brittle, worn or otherwise in obvious need of replacement. Others may look okay, but do a lousy job of wiping when put to the test.
Ninety percent of all driving decisions are based on a clear unobstructed view of the road, which means good visibility is absolutely essential -- especially during wet weather when vision may be obscured by water, road splash, sleet or snow on the windshield. But good visibility requires wipers that are in good condition. If the wipers are chattering, streaking or otherwise failing to wipe cleanly and consistently, you need new blades -- NOW!
Most experts say wiper blades should be replaced every six to twelve months for optimum performance and driving visibility. That's because wiper blades don't last forever. Natural rubber deteriorates over time. Halogen-hardened rubber as well as synthetic rubber provides longer life. But eventually all blade materials fall victim to environmental factors. Exposure to sunlight and ozone causes the rubber to age, even if the wipers aren't used much.
As a set of blades age, they lose much of their flip-over flexibility and they're less able to wipe cleanly. They may develop a permanent set (called "parked" rubber) or curvature which prevents full contact with the windshield. This tends to be more of a problem on vehicles that are parked outside in the hot sun all day. The sun bakes and hardens the rubber. Then when the wipers are needed, they streak and chatter because they've taken a set and won't follow the curvature of the windshield. It can be very annoying as well as dangerous.
Cold weather can affect blade life, too. Freezing temperatures makes rubber hard and brittle, which increases the tendency to crack and split. The holders can also become clogged with ice and snow, preventing the holder from distributing spring tension evenly over the blade. The blade "freezes up" and leaves streaks as it skips across the glass.
Heavy use can be hard on wiper blades, too, because dust, abrasives, road grime and even bug juice wear away the edge that the blades need to wipe cleanly. As the blade loses its edge (which is precision cut square to maximize the squeegee effect), water gets under the blade and remains on the glass. The result is reduced visibility and poor wiping action.
Any blade that's chattering, streaking or doing a lousy job of wiping, therefore, is a blade that's overdue for replacement. The same goes for any blade that is cracked, torn, nicked or otherwise damaged.
CHECKING YOUR BLADES
A simple check is to try your windshield washers. If the blades are not in good condition, you'll see why when they attempt to wipe the washer solvent off the glass. Streaking, chattering or any other problems will be clearly obvious.
This test also gives you the opportunity to check your windshield washer system. Do both squirters work? If not, a nozzle may be plugged with dirt or a hose may be kinked or loose. Does the spray hit the windshield where it is supposed to? If not, the nozzles need adjusting. Does the washer pump deliver an adequate stream of solvent? If not, the vehicle may have a weak washer pump, or a clogged, kinked or loose hose. Most washer reservoirs have a screen to filter out debris that could clog or damage the pump. If this screen itself is buried under debris, it can choke off the flow of solvent to the washers.
After you've checked the windshield wipers, check the rear wiper too if your vehicle has a rear wiper system. Many sport utility vehicles, vans, minivans, station wagons, hatchbacks and fastbacks do. After all, it's just as important to see what's behind you when backing up in the rain as it is to see what's ahead. You can use the same test (try the rear windshield washer, if so equipped), or simply spray some water onto the glass with a squeeze bottle and see how the wiper performs.
OTHER FACTORS THAT AFFECT YOUR WIPERS
How well the wiper blades perform also depends on the condition of the wiper arms and holders. A blade's wiping ability is affected by the amount of spring tension on the wiper arm, the number of pressure points or claws that hold the blade, and the design of the blade itself. If the springs in the arms are weak (which is more apt to be a problem in older vehicles), the wipers may not be pressed against the glass firmly enough to wipe cleanly. Replacing the blades won't make any difference because the problem is weak arms not bad blades.
If the blades can be pulled away from the glass with little resistance, it's time for new arms. Most vehicle manufacturers publish tension specs for their arms. If the arm doesn't meet the spec, it needs to be replaced.
Remember to check the tension on the rear wiper arm, too, because rear wiper arms are often damaged by drive-through car wash rollers.
Wind lift is another factor that can interfere with good wiping action at highway speeds. Many windshields are steeply sloped to improve aerodynamics. But steeply raked windshields with a lot of glass area direct more wind against the wipers. This can lift the blades away from the glass at high speed unless the wiper system and blades are designed to counter the aerodynamic forces. Some blades have specially designed vents and airfoils to minimize lift and/or generate downforce to keep the blades in constant contact with the glass as speed increases. If your original equipment blade holders need to be replaced, be sure the replacements have the same anti-wind lift design.
Another factor to keep in mind is the design of the blade holder. A blade holder needs to distribute the tension of the wiper arm evenly over the blade while also allowing the blade to flex as it follows the changing curvature of the glass. The better quality replacement blade holders typically have six to eight claws to spread the pressure of the wiper arm over the blade. More claws also increases flexibility so the blades don't lose contact at the sides of the glass.
REPLACEMENT BLADES
You can usually replace wiper blades yourself, and can replace just the blade with a refill or the entire blade assembly. Refills will save you money. If you're installing a blade assembly, most come with some type of adapter to fit the arms on your vehicle. The old blades pull or push off the arm by pressing a release button or pin on the wiper holder.
If you are replacing the blade only with a refill, the old blade can be removed by squeezing the locking tags in at the end of the blade so it will slip out of the holder. Make sure the replacement blade is the same length and claw width as the original. A blade that is too long may create interference problems, while one that is too short may not fit the holder.
For cold weather driving, you might consider installing a set of "winter blades" on your vehicle. These have an enclosed holder that prevents ice and snow from building up and interfering with the wiper's ability to do its job.
Showing posts with label Under hood Maintenance. Show all posts
Showing posts with label Under hood Maintenance. Show all posts
Wednesday, January 30, 2008
Under hood Maintenance: Transmission Oil/Fluid
Check Manual Transmission Lubricant Level
The manual transmission is lubricated by a lubricant that is splashed throughout the transmission by the moving gears. The lubricant must be at the correct level or the transmission parts could wear out in a very short time. The interval for lubrication level check is specified in the maintenance schedule in the owner's manual. Most technicians make this check whenever the car is up on a hoist for an undercar inspection.
Some imported cars have a dipstick to check manual transmission fluid level. This dipstick is found under the hood. The engine must be off to check the fluid with a dipstick. Remove and wipe the dipstick with a clean rag. Then insert the dipstick back into position. Remove it again and note the reading. Lubricant must be between the "full" and "add" marks on the dipstick. When you are done, replace the dipstick.
CAUTION: Make manual transmission checks with the engine off. Never put your finger into a transmission fill plug hole. If the drive wheels are turned, your finger could be caught in the gearing.
WARNING: A car that is not level on a hoist or jack will not show a true lubricant level in the transmission. If the engine has been running, allow two or three minutes before checking for a more accurate reading.
You will have to check most cars up on the hoist or jack. Raise the car and be sure it is level. Locate the transmission fill plug on the side of the transmission. You may have difficulty locating it. If you do, look for an identification diagram like the one shown below. Do not confuse the fill plug with the drain plug, which is located at the bottom of the transmission.
Clean the area around the fill plug to avoid getting dirt into the transmission. Remove the fill plug with the correct size wrench. If the transmission is full, you may see lubricant begin to leak out of the fill plug hole. If this happens, replace the plug.
You will probably find that the lubricant level is below the level of the fill plug hole. Bend a short length of metal wire and insert it into the fill hole. Pull the wire out and note the lubricant on the end of the wire. The lubricant level should be very close to the level of the fill plug.
If the lubricant level is satisfactory, replace the fill plug. If the level is low, add lubricant as explained in the next section.
Drain and Refill Manual Transmission Lubricant
The car manufacturer specifies regular time and or mileage intervals for the changing of manual transmission lubricant. You can find this information in the owner's or shop service manual. You will also need to look up the type and quantity of lubricant required. A lubricant chart can usually be found in a shop manual.
WARNING: Manual transmissions for different cars use many different types of lubricants. These include engine oil, automatic transmission fluid, and gear lubricant. Always determine and use the correct lubricant type. The incorrect lubricant can cause major damage to the transmission.
Drive the car long enough to heat up the lubricant. Lift the car on a hoist or jack and jack stands. The car must be level for accurate refilling of the transmission. Locate the drain and fill plug on the transmission as described in the previous section.
CAUTION: Be careful when draining a transmission because the oil could be hot enough to cause burns.
Position a clean drain pan under the drain plug. Clean around the area of the fill and drain plug. Remove the drain and fill plugs and allow the transmission to drain.
Inspect the fluid that collects in the drain pan. Look for metal in the oil. Metal shows up as shiny, metal particles or flakes. An excessive amount of metal could mean internal damage to transmission components.
When the lubricant is completely drained, clean the drain plug. Replace any sealing washer or use the recommended type of sealant on the drain plug threads. Install the drain plug and tighten it to the recommended torque.
The new lubricant will need to be pumped into the transmission through the fill plug hole. There are two types of lubricant pumps. Small hand pumps that attach to the container of lubricant are available at auto parts stores. Larger containers hold several gallons of lubricant. These have a hand pump that forces the lubricant through a hose and out a nozzle.
Place the delivery nozzle from the pump into the fill plug hole. Slowly pump the lubricant into the transmission. Stop pumping a few seconds after each pump to give the lubricant time to flow to the bottom of the transmission. Stop filling when the lubricant reaches the bottom of the fill plug hole. Wait several minutes, then check the level again. Sometimes the level will drop as the lubricant settles to the bottom of the transmission. Install the fill plug and wipe away any spilled fluid.
Check Automatic Transmission/Transaxle Fluid Level and Condition
Automatic transmission or automatic transaxle fluid should be checked at regular mileage and time intervals as specified in the owner's manual. Anytime you are doing lubrication work on a car you should check the fluid level.
Make sure the engine and transmission are up to operating temperature. Locate the fluid level checking procedure in the owner's or shop service manual. Drive the car onto a level surface. Most cars must have the engine running to make a fluid level check. Some cars must have the transmission in NEUTRAL and others require that it be in PARK for testing. Set the selector in the correct mode. If the transmission is checked in NEUTRAL, block the wheels and set the parking brake.
WARNING: Failure to have the transmission in the correct gear when checking fluid level can cause a large error in the reading.
Raise the hood and locate the automatic transmission/transaxle dipstick. Typically you will find the dipstick near the transmission end of the engine at the opposite end of the drive belts.
WARNING: Never wipe a dipstick with a rag with lint. Lint from a rag could get into transmission control valves and cause them to stick. It could also plug up fluid passages. Use only lint-free rags or shop towels.
Remove the dipstick and wipe it with a clean, lint-free rag. Observe the markings on the dipstick. There is no standard marking system, so you may need to look up an explanation of the marks in the owner's manual. A typical marking system is shown below. This dipstick has a full hot level mark and an add 1 pt (pint) or 0.5 L. (liter) mark. The word hot means the fluid must be hot when checked. There can be a large difference in fluid level between hot and cold fluid levels. Some dipsticks have a cold reading on the dipstick, which should be used if the transmission is cold.
Insert the dipstick back into its housing and push it down until it seats. Pull it back out and observe the fluid level in relation to the dipstick markings. If fluid must be added, refer to the section on adding fluid.
While you have the fluid on the dipstick you should observe its color and condition. This information can help you decide if the fluid requires changing. Clean, uncontaminated fluid has a pinkish or reddish color. Fluid that has been overheated turns a darkish brown or black. A white milky appearance can mean that the engine coolant is leaking into the transmission.
Another fluid check to make is to wipe the fluid off the dipstick with a white absorbent paper. Look for foreign particles in the fluid. Silvery particles can mean there is wear on metallic parts. Dark particles can be friction material that has come off transmission parts. Also look for a dark gummy material on the dipstick. This is usually a varnish buildup in the fluid. Fluid that shows any of these problems should be changed, as explained in the following section. Replace the dipstick and make sure it is seated properly.
Drain Fluid, Change Filter, and Refill Automatic Transmission/Transaxle Fluid
The fluid in an automatic transmission or automatic transaxle has many important jobs to perform. All of these depend on the fluid being clean and in good condition. Fluid should be changed if your dipstick test shows any of the problems described previously. Fluid should also be changed at the regular time and mileage interval specified in the owner's manual.
The first step in fluid changing is to get the transmission/transaxle up to normal operating temperature. The contaminants in the fluid will flow out better when the fluid is warm.
Raise the car on a hoist or support it on a jack and safety stands. Place a large drain pan under the transmission area. Some transmissions have a drain plug. If the car you are working on has one, use the correct size wrench to remove it as shown below.
CAUTION: Wear eye protection when draining a transmission/transaxle to protect your eyes against hot fluid splash. Be careful not to spill hot fluid on yourself.
Many transmissions do not have a drain plug. In these cases the manufacturer wants the technician to remove the pan and to change the fluid filter. To remove the oil pan, first remove any parts that interfere with the oil pan being removed. Use the correct size wrench to loosen but do not remove all the pan bolts. Remove all the bolts except the ones on one end. These bolts will keep the pan from falling off while the fluid drains. Make sure your drain pan is in position. Gently tap the pan with a rubber mallet to get it to break free of the transmission.
WARNING: Never use any tool to pry between the pan and the transmission/transaxle sealing surface. If you damage this surface, the transmission pan may not seal properly and will leak.
Allow the transmission to drain. Then remove the remaining bolts and the pan. Carefully check the bottom of the pan for foreign material. The material that collects in the pan is a good indicator of the transmission condition. A small amount of deposits from friction and metal parts is normal. A buildup of particles of metal or friction material is a sign of transmission wear.
Carefully remove the old gasket from the pan. Do not use any sharp tool to scrape the gasket or the sealing surface could be damaged. Use a lint-free rag to clean the pan.
Now you are ready to change or clean the fluid filter or screen. The filter or screen is mounted on the bottom of the valve body assembly as shown below. The filter or screen works like the oil filter in the engine. It cleans the fluid being pumped into the transmission parts from the pan. The filter or screen must be changed or cleaned each time you change the fluid.
WARNING: Before removing any filter or screen, check the procedure in a shop service manual. Some transmissions use the screen or filter to hold some small check valves and springs in position. These valves can fall out if the filter or screen is not carefully removed.
Filters and screens are often held in place with several screws. These screws may be regular Phillips or hex head or special torx head type. Use a torx head screwdriver to remove these screws. Some screws may be longer than others. Be careful to note size differences so you can reinstall them in the correct position.
There are two basic types of filters. One type is made from paper or cotton. This type is made to be replaced. The screen type has a metal screen with a washable filter element inside. This type is made to be cleaned and reused. Wash the replaceable screen with recommended solvent or spray cleaner and air dry.
When you are ready to reassemble, place the new pan gasket and filter next to the old ones. They will match up if they are the correct parts. Install the new filter or cleaned screen on the valve body and tighten all the fasteners to the correct tightening specifications.
Place the new gasket on the sealing surface of the fluid pan. Check the shop service manual for recommendations regarding any sealant to be used on the gasket. Also look up the pan bolt tightening sequence and the required torque. Place the pan and gasket in position and start all the screws. Use the correct type torque wrench to tighten the bolts in the correct sequence and correct torque.
WARNING: Some pan tightening specifications call for the use of an inch-pound torque wrench. Do not confuse these specifications and use a foot-pound torque wrench. Mixing up these specifications could cause the part to be over-tightened and damaged.
Most late model cars do not require that the torque converter be drained. Although there are no drain plugs on most late-model torque converters, some older cars do have them. Torque converter drain plugs are often found by removing an access cover on the bottom of the torque converter housing. The engine then has to be cranked until the drain plug on the torque converter appears in the access hole as shown below. Then follow the procedure for draining the fluid.
When you have finished your work underneath the car, lower it to the floor. You will need the specifications from the owner's or shop service manual on the type and amount of fluid to add to the transmission/transaxle. Some specifications list the amount of fluid required for a pan draining and a larger amount if the torque converter is drained. Be sure not to confuse these amounts.
WARNING: Use only the recommended type of fluid. Using an incorrect fluid type can damage some transmission friction parts.
Open the hood and remove the transmission/transaxle dipstick. Install a clean funnel in the dipstick and filler tube. Open and pour the recommended amount of fluid into the transmission/transaxle through the funnel. Remove the funnel and replace the dipstick.
Start the engine and allow the engine and transmission to warm up to operating temperature. With your foot on the brakes and the parking brake set, move the gear selector through each of the gear selections. Doing this allows the fluid to circulate through the entire transmission. Place the transmission in the correct gear for fluid checking and recheck the fluid level with the dipstick. Correct the fluid level if necessary. Test drive the car and check for proper transmission/transaxle operation.
WARNING: The fluid level is critical to proper transmission/transaxle operation. Too high a fluid level can cause rotating parts in the transmission to whip the fluid up and cause air bubbles. Air in the fluid can cause transmission slippage. Low fluid level can also cause air in the fluid and erratic transmission operation.
The manual transmission is lubricated by a lubricant that is splashed throughout the transmission by the moving gears. The lubricant must be at the correct level or the transmission parts could wear out in a very short time. The interval for lubrication level check is specified in the maintenance schedule in the owner's manual. Most technicians make this check whenever the car is up on a hoist for an undercar inspection.
Some imported cars have a dipstick to check manual transmission fluid level. This dipstick is found under the hood. The engine must be off to check the fluid with a dipstick. Remove and wipe the dipstick with a clean rag. Then insert the dipstick back into position. Remove it again and note the reading. Lubricant must be between the "full" and "add" marks on the dipstick. When you are done, replace the dipstick.
CAUTION: Make manual transmission checks with the engine off. Never put your finger into a transmission fill plug hole. If the drive wheels are turned, your finger could be caught in the gearing.
WARNING: A car that is not level on a hoist or jack will not show a true lubricant level in the transmission. If the engine has been running, allow two or three minutes before checking for a more accurate reading.
You will have to check most cars up on the hoist or jack. Raise the car and be sure it is level. Locate the transmission fill plug on the side of the transmission. You may have difficulty locating it. If you do, look for an identification diagram like the one shown below. Do not confuse the fill plug with the drain plug, which is located at the bottom of the transmission.
Clean the area around the fill plug to avoid getting dirt into the transmission. Remove the fill plug with the correct size wrench. If the transmission is full, you may see lubricant begin to leak out of the fill plug hole. If this happens, replace the plug.
You will probably find that the lubricant level is below the level of the fill plug hole. Bend a short length of metal wire and insert it into the fill hole. Pull the wire out and note the lubricant on the end of the wire. The lubricant level should be very close to the level of the fill plug.
If the lubricant level is satisfactory, replace the fill plug. If the level is low, add lubricant as explained in the next section.
Drain and Refill Manual Transmission Lubricant
The car manufacturer specifies regular time and or mileage intervals for the changing of manual transmission lubricant. You can find this information in the owner's or shop service manual. You will also need to look up the type and quantity of lubricant required. A lubricant chart can usually be found in a shop manual.
WARNING: Manual transmissions for different cars use many different types of lubricants. These include engine oil, automatic transmission fluid, and gear lubricant. Always determine and use the correct lubricant type. The incorrect lubricant can cause major damage to the transmission.
Drive the car long enough to heat up the lubricant. Lift the car on a hoist or jack and jack stands. The car must be level for accurate refilling of the transmission. Locate the drain and fill plug on the transmission as described in the previous section.
CAUTION: Be careful when draining a transmission because the oil could be hot enough to cause burns.
Position a clean drain pan under the drain plug. Clean around the area of the fill and drain plug. Remove the drain and fill plugs and allow the transmission to drain.
Inspect the fluid that collects in the drain pan. Look for metal in the oil. Metal shows up as shiny, metal particles or flakes. An excessive amount of metal could mean internal damage to transmission components.
When the lubricant is completely drained, clean the drain plug. Replace any sealing washer or use the recommended type of sealant on the drain plug threads. Install the drain plug and tighten it to the recommended torque.
The new lubricant will need to be pumped into the transmission through the fill plug hole. There are two types of lubricant pumps. Small hand pumps that attach to the container of lubricant are available at auto parts stores. Larger containers hold several gallons of lubricant. These have a hand pump that forces the lubricant through a hose and out a nozzle.
Place the delivery nozzle from the pump into the fill plug hole. Slowly pump the lubricant into the transmission. Stop pumping a few seconds after each pump to give the lubricant time to flow to the bottom of the transmission. Stop filling when the lubricant reaches the bottom of the fill plug hole. Wait several minutes, then check the level again. Sometimes the level will drop as the lubricant settles to the bottom of the transmission. Install the fill plug and wipe away any spilled fluid.
Check Automatic Transmission/Transaxle Fluid Level and Condition
Automatic transmission or automatic transaxle fluid should be checked at regular mileage and time intervals as specified in the owner's manual. Anytime you are doing lubrication work on a car you should check the fluid level.
Make sure the engine and transmission are up to operating temperature. Locate the fluid level checking procedure in the owner's or shop service manual. Drive the car onto a level surface. Most cars must have the engine running to make a fluid level check. Some cars must have the transmission in NEUTRAL and others require that it be in PARK for testing. Set the selector in the correct mode. If the transmission is checked in NEUTRAL, block the wheels and set the parking brake.
WARNING: Failure to have the transmission in the correct gear when checking fluid level can cause a large error in the reading.
Raise the hood and locate the automatic transmission/transaxle dipstick. Typically you will find the dipstick near the transmission end of the engine at the opposite end of the drive belts.
WARNING: Never wipe a dipstick with a rag with lint. Lint from a rag could get into transmission control valves and cause them to stick. It could also plug up fluid passages. Use only lint-free rags or shop towels.
Remove the dipstick and wipe it with a clean, lint-free rag. Observe the markings on the dipstick. There is no standard marking system, so you may need to look up an explanation of the marks in the owner's manual. A typical marking system is shown below. This dipstick has a full hot level mark and an add 1 pt (pint) or 0.5 L. (liter) mark. The word hot means the fluid must be hot when checked. There can be a large difference in fluid level between hot and cold fluid levels. Some dipsticks have a cold reading on the dipstick, which should be used if the transmission is cold.
Insert the dipstick back into its housing and push it down until it seats. Pull it back out and observe the fluid level in relation to the dipstick markings. If fluid must be added, refer to the section on adding fluid.
While you have the fluid on the dipstick you should observe its color and condition. This information can help you decide if the fluid requires changing. Clean, uncontaminated fluid has a pinkish or reddish color. Fluid that has been overheated turns a darkish brown or black. A white milky appearance can mean that the engine coolant is leaking into the transmission.
Another fluid check to make is to wipe the fluid off the dipstick with a white absorbent paper. Look for foreign particles in the fluid. Silvery particles can mean there is wear on metallic parts. Dark particles can be friction material that has come off transmission parts. Also look for a dark gummy material on the dipstick. This is usually a varnish buildup in the fluid. Fluid that shows any of these problems should be changed, as explained in the following section. Replace the dipstick and make sure it is seated properly.
Drain Fluid, Change Filter, and Refill Automatic Transmission/Transaxle Fluid
The fluid in an automatic transmission or automatic transaxle has many important jobs to perform. All of these depend on the fluid being clean and in good condition. Fluid should be changed if your dipstick test shows any of the problems described previously. Fluid should also be changed at the regular time and mileage interval specified in the owner's manual.
The first step in fluid changing is to get the transmission/transaxle up to normal operating temperature. The contaminants in the fluid will flow out better when the fluid is warm.
Raise the car on a hoist or support it on a jack and safety stands. Place a large drain pan under the transmission area. Some transmissions have a drain plug. If the car you are working on has one, use the correct size wrench to remove it as shown below.
CAUTION: Wear eye protection when draining a transmission/transaxle to protect your eyes against hot fluid splash. Be careful not to spill hot fluid on yourself.
Many transmissions do not have a drain plug. In these cases the manufacturer wants the technician to remove the pan and to change the fluid filter. To remove the oil pan, first remove any parts that interfere with the oil pan being removed. Use the correct size wrench to loosen but do not remove all the pan bolts. Remove all the bolts except the ones on one end. These bolts will keep the pan from falling off while the fluid drains. Make sure your drain pan is in position. Gently tap the pan with a rubber mallet to get it to break free of the transmission.
WARNING: Never use any tool to pry between the pan and the transmission/transaxle sealing surface. If you damage this surface, the transmission pan may not seal properly and will leak.
Allow the transmission to drain. Then remove the remaining bolts and the pan. Carefully check the bottom of the pan for foreign material. The material that collects in the pan is a good indicator of the transmission condition. A small amount of deposits from friction and metal parts is normal. A buildup of particles of metal or friction material is a sign of transmission wear.
Carefully remove the old gasket from the pan. Do not use any sharp tool to scrape the gasket or the sealing surface could be damaged. Use a lint-free rag to clean the pan.
Now you are ready to change or clean the fluid filter or screen. The filter or screen is mounted on the bottom of the valve body assembly as shown below. The filter or screen works like the oil filter in the engine. It cleans the fluid being pumped into the transmission parts from the pan. The filter or screen must be changed or cleaned each time you change the fluid.
WARNING: Before removing any filter or screen, check the procedure in a shop service manual. Some transmissions use the screen or filter to hold some small check valves and springs in position. These valves can fall out if the filter or screen is not carefully removed.
Filters and screens are often held in place with several screws. These screws may be regular Phillips or hex head or special torx head type. Use a torx head screwdriver to remove these screws. Some screws may be longer than others. Be careful to note size differences so you can reinstall them in the correct position.
There are two basic types of filters. One type is made from paper or cotton. This type is made to be replaced. The screen type has a metal screen with a washable filter element inside. This type is made to be cleaned and reused. Wash the replaceable screen with recommended solvent or spray cleaner and air dry.
When you are ready to reassemble, place the new pan gasket and filter next to the old ones. They will match up if they are the correct parts. Install the new filter or cleaned screen on the valve body and tighten all the fasteners to the correct tightening specifications.
Place the new gasket on the sealing surface of the fluid pan. Check the shop service manual for recommendations regarding any sealant to be used on the gasket. Also look up the pan bolt tightening sequence and the required torque. Place the pan and gasket in position and start all the screws. Use the correct type torque wrench to tighten the bolts in the correct sequence and correct torque.
WARNING: Some pan tightening specifications call for the use of an inch-pound torque wrench. Do not confuse these specifications and use a foot-pound torque wrench. Mixing up these specifications could cause the part to be over-tightened and damaged.
Most late model cars do not require that the torque converter be drained. Although there are no drain plugs on most late-model torque converters, some older cars do have them. Torque converter drain plugs are often found by removing an access cover on the bottom of the torque converter housing. The engine then has to be cranked until the drain plug on the torque converter appears in the access hole as shown below. Then follow the procedure for draining the fluid.
When you have finished your work underneath the car, lower it to the floor. You will need the specifications from the owner's or shop service manual on the type and amount of fluid to add to the transmission/transaxle. Some specifications list the amount of fluid required for a pan draining and a larger amount if the torque converter is drained. Be sure not to confuse these amounts.
WARNING: Use only the recommended type of fluid. Using an incorrect fluid type can damage some transmission friction parts.
Open the hood and remove the transmission/transaxle dipstick. Install a clean funnel in the dipstick and filler tube. Open and pour the recommended amount of fluid into the transmission/transaxle through the funnel. Remove the funnel and replace the dipstick.
Start the engine and allow the engine and transmission to warm up to operating temperature. With your foot on the brakes and the parking brake set, move the gear selector through each of the gear selections. Doing this allows the fluid to circulate through the entire transmission. Place the transmission in the correct gear for fluid checking and recheck the fluid level with the dipstick. Correct the fluid level if necessary. Test drive the car and check for proper transmission/transaxle operation.
WARNING: The fluid level is critical to proper transmission/transaxle operation. Too high a fluid level can cause rotating parts in the transmission to whip the fluid up and cause air bubbles. Air in the fluid can cause transmission slippage. Low fluid level can also cause air in the fluid and erratic transmission operation.
Under hood Maintenance: Power Steering Fluid
Most cars today are equipped with a power steering system. Many power steering systems use hydraulic power. These systems use a power steering pump driven by a belt from the crankshaft. The pump moves fluid under pressure through hoses to the steering gear. The pressure is used in the steering gear to reduce steering effort. A reservoir for fluid is attached to the rear of the pump. Checking the fluid level in this reservoir is a common underhood maintenance job.
The fluid in the power steering system provides lubrication as well as the power assist. Low fluid level can cause a lack of power assist, excessive noise, and rapid part wear. The power steering fluid level should be checked at regular intervals.
CAUTION: Check the fluid level with the engine off to prevent possible injury from moving parts.
The fluid is checked at the pump reservoir with a dipstick attached to the reservoir cap. . Before removing the reservoir cap, wipe the outside of the cap and reservoir to prevent dirt from falling into the reservoir. Pull the dipstick out and note the fluid reading. The fluid should be between the "hot" and "cold" mark on the dipstick. There are hot and cold marks because the fluid expands as it gets hot. If the level is below the "add" mark, you will have to add fluid to bring it up to the correct level. You should use only the type of fluid listed in the owner's or shop service manual. Older cars use automatic transmission fluid. Special power steering fluids are used on late-model cars. Add the correct amount of fluid and replace the dipstick.
Q & A: Power steering fluid
Question:
1. My power steering feels stiff when I first start my car, but then feels normal after I've driven the car awhile. How come?
Answer:
This is called "morning sickness" and has nothing to do with being pregnant. The condition is caused by wear in the spool valve housing on certain power steering racks -- notably GM front-wheel drive cars.
When the car is first started, the rack is cold and clearances in the spool valve are at their greatest. Hydraulic pressure from the power steering pump leaks past grooves worn in the aluminum spool valve housing. This causes a loss of pressure and increases steering effort. The steering feels stiff with little or no power assist. As the car is driven, the rack warms up. This decreases the clearances inside the spool valve housing, which reduces the leakage past the grooves. More pressure goes to where it is supposed to go and the steering becomes easier as power assist returns.
The "fix" for this condition is to replace the rack with a new one (preferably with a cast iron spool valve housing) or a remanufactured rack that has a stainless steel sleeve pressed into the aluminum housing.
Question:
2. Does the power steering fluid ever need to be changed?
Answer:
Not normally, but it should be if the steering rack or pump are ever replaced. Under normal circumstances, the fluid in the power steering system should last the life of the vehicle (or the life of the major power steering components, whichever comes first). But as the system accumulates miles, microscopic particles of metal and rubber can buildup in the fluid. These particles can act like an abrasive and accelerate pump and gear wear, so the fluid should be changed if the original pump or rack has failed to prevent contaminating the new parts with dirty fluid.
CHECK PERIODICALLY
Even though the fluid in your power steering system does not normally require changing, it's a good idea to check the fluid level periodically (say once a month or when changing the engine oil and filter).
If the level is low, add fluid as needed to bring it up to the full level (hot or cold). Then inspect the hoses, pump and steering gear for leaks. More than a few ounces of fluid in the rubber bellows of a power steering rack indicates internal wear and leakage.
Always use the type of fluid specified by the vehicle manufacturer (Dexron II or a special blend of power steering fluid).
The fluid in the power steering system provides lubrication as well as the power assist. Low fluid level can cause a lack of power assist, excessive noise, and rapid part wear. The power steering fluid level should be checked at regular intervals.
CAUTION: Check the fluid level with the engine off to prevent possible injury from moving parts.
The fluid is checked at the pump reservoir with a dipstick attached to the reservoir cap. . Before removing the reservoir cap, wipe the outside of the cap and reservoir to prevent dirt from falling into the reservoir. Pull the dipstick out and note the fluid reading. The fluid should be between the "hot" and "cold" mark on the dipstick. There are hot and cold marks because the fluid expands as it gets hot. If the level is below the "add" mark, you will have to add fluid to bring it up to the correct level. You should use only the type of fluid listed in the owner's or shop service manual. Older cars use automatic transmission fluid. Special power steering fluids are used on late-model cars. Add the correct amount of fluid and replace the dipstick.
Q & A: Power steering fluid
Question:
1. My power steering feels stiff when I first start my car, but then feels normal after I've driven the car awhile. How come?
Answer:
This is called "morning sickness" and has nothing to do with being pregnant. The condition is caused by wear in the spool valve housing on certain power steering racks -- notably GM front-wheel drive cars.
When the car is first started, the rack is cold and clearances in the spool valve are at their greatest. Hydraulic pressure from the power steering pump leaks past grooves worn in the aluminum spool valve housing. This causes a loss of pressure and increases steering effort. The steering feels stiff with little or no power assist. As the car is driven, the rack warms up. This decreases the clearances inside the spool valve housing, which reduces the leakage past the grooves. More pressure goes to where it is supposed to go and the steering becomes easier as power assist returns.
The "fix" for this condition is to replace the rack with a new one (preferably with a cast iron spool valve housing) or a remanufactured rack that has a stainless steel sleeve pressed into the aluminum housing.
Question:
2. Does the power steering fluid ever need to be changed?
Answer:
Not normally, but it should be if the steering rack or pump are ever replaced. Under normal circumstances, the fluid in the power steering system should last the life of the vehicle (or the life of the major power steering components, whichever comes first). But as the system accumulates miles, microscopic particles of metal and rubber can buildup in the fluid. These particles can act like an abrasive and accelerate pump and gear wear, so the fluid should be changed if the original pump or rack has failed to prevent contaminating the new parts with dirty fluid.
CHECK PERIODICALLY
Even though the fluid in your power steering system does not normally require changing, it's a good idea to check the fluid level periodically (say once a month or when changing the engine oil and filter).
If the level is low, add fluid as needed to bring it up to the full level (hot or cold). Then inspect the hoses, pump and steering gear for leaks. More than a few ounces of fluid in the rubber bellows of a power steering rack indicates internal wear and leakage.
Always use the type of fluid specified by the vehicle manufacturer (Dexron II or a special blend of power steering fluid).
Under hood Maintenance: Engine oil
Question:
My engine uses about a quart of oil every 1,000 miles. Should I be concerned?
Answer:
Not if you plan to sell or trade your vehicle soon. An engine that uses a quart of oil every 1,000 miles is starting to show the effects of wear. The amount of oil it is using is still acceptable, but it will gradually increase as the miles add up. When it reaches the point where it's using a quart every 500 miles or less, it's time for an overhaul.
Oil consumption depends primarily on two things: the valve guides and piston rings. If the valve guides are worn, or if there's too much clearance between the valve stems and guides, or if the valve guide seals are worn, cracked, missing, broken or improperly installed, the engine will suck oil down the guides and into the cylinders. The engine may still have good compression, but will use a lot of oil.
An oil consumption problem caused by worn valve guides can usually be cured by a valve job. Knurling or replacing the guides or boring out the guides and installing valves with oversized stems will stop the loss of oil.
Oil can also get past the rings if the rings or cylinders are badly worn or damaged, if the cylinders were not honed properly when the engine was built (or rebuilt), or if the rings were installed improperly.
When a newly-built engine is first started, the rings require a certain amount of time to "seat" or break-in. If the rings fail to seat properly, the engine will use oil. This may be the case if somebody applied the wrong finish to the cylinders, failed to clean and lubricate the cylinders properly before the engine was fired up, or didn't use the proper break-in procedure.
If the rings and/or cylinders are at fault, the engine will have lower than normal compression readings.
In some instances, worn rod bearings, excessive bearing clearances and/or excessive oil pressure can splash too much oil on the cylinders causing oil to get past the rings.
The cure for worn rings and cylinders is to overhaul the engine block. The cylinders have to be refinished and new rings installed to regain good oil control.
Question:
My engine is leaking oil past the valve cover gaskets. I've tried tightening down the valve cover bolts, but it doesn't seem to help. What should I do?
Answer:
Bite the bullet and buy a new set of valve cover gaskets. Most cork valve cover gaskets usually cost less than $20 and are fairly easy to install on many engines. You may have to disconnect and remove some plumbing or other accessories to get to the valve covers, but on many engines the job is usually within the capabilities of a do-it-yourselfer. If the valve covers are buried or access is difficult, then let a professional replace the gaskets for you.
Tightening the valve cover bolts or screws will rarely stop an oil leak because the gasket is usually cracked, crushed or has lost its natural elasticity. Cork gaskets only last about four to six years before they age harden, become brittle and start to leak. Molded silicone rubber gaskets, on the other hand, (which are used on many late model domestic and import engines) often last the life of the engine. But molded rubber gaskets are a lot more expensive than die cut cork gaskets. That's why cork gaskets have long been used by the vehicle manufacturers.
Some engines do not have gaskets, but instead use a rubbery-glue called "RTV silicone sealer (the "RTV" stands for Room Temperature Vulcanizing). If this is the case, you can remove the valve cover, scrape off all the old RTV, and either apply a fresh bead of RTV silicone sealer to the valve cover flange or head mating surface or install a conventional gasket.
CAUTION: Do not let any pieces of rubber or debris fall into the engine. Also, if you decide to use RTV sealer and your engine has an oxygen sensor (which almost all 1981 and later engines do), make sure the RTV sealer is the "low volatile" variety that is approved for use with oxygen sensors. Some types of RTV give off silicone vapor that can be sucked through the crankcase and contaminate the oxygen sensor.
Question: Is it better to maintain my engine's oil level at the full mark or wait until it reaches the "add" mark to add oil?
Answer: Most vehicle manufacturers say it's okay to wait until the level reaches the add mark to add oil. The add mark is typically one quart below the full mark on the dip stick.Considering that the crankcase capacity on most passenger cars today is only four quarts, running the engine 25% low on oil (one quart) may not be wise. Here's why.
Oil not only lubricates the engine's internal parts, but also helps cool the bearings. The total amount of oil in the engine, therefore, serves as a heat sink to help control heat. Under normal driving conditions, running a quart low probably doesn't make much difference in terms of bearing temperature or overall engine lubrication. But during extremely hot weather, when driving at sustained highway speeds and/or when towing a trailer, running a quart low may increase the risk of accelerated engine wear and/or damage.
The best advice, therefore, is to add oil whenever the dipstick reads low. Don't wait until it is down a full quart. If it needs half a quart, add half a quart to bring it back up to the full mark.
CAUTION: Do not overfill the engine. Adding too much oil can overfill the crankcase. As the crankshaft spins around, it can whip the oil into foam if the level is too high. This, in turn, can cause a drop in oil pressure and loss of lubrication to critical engine parts. Also, too much oil may cause leaks as the extra oil is forced past seals and gaskets.
Follow your vehicle manufacturer's guidelines for the type and viscosity of oil to use in your engine.
Question:
How often should I change my oil?
Answer:
Most vehicle manufacturers recommend changing the oil once a year or every 7,500 miles in passenger car and light truck gasoline engines. For diesel engines and turbocharged gasoline engines, the usual recommendation is every 3,000 miles or six months.
If you read the fine print, however, you'll discover that the once a year, 7,500 mile oil change is for vehicles that are driven under ideal circumstances. What most of us think of as "normal" driving is actually "severe service" driving. This includes frequent short trips (less than 10 miles, especially during cold weather), stop-and-go city traffic driving, driving in dusty conditions (gravel roads, etc.), and driving at sustained highway speeds during hot weather. For this type of driving, which is actually "severe service: driving, the recommendation is to change the oil every 3,000 miles or six months.
For maximum protection, most oil companies say to change the oil every 3,000 miles or three to six months regardless of what type of driving you do.
A new engine with little or no wear can probably get by on 7,500 mile oil changes. But as an engine accumulates miles, blow by increases. This dumps more unburned fuel into the crankcase which dilutes the oil. This causes the oil to break down. So if the oil isn't changed often enough, you can end up with accelerated wear and all the engine problems that come with it (loss of performance and fuel economy, and increased emissions and oil consumption).
OIL ANALYSIS
Truck fleets often monitor the condition of the oil in their vehicles by having samples analyzed periodically. Oil samples are sent to a laboratory that then analyzes the oil's viscosity and acid content. Oil is then burned in a device called a spectrometer that reveals various impurities in the oil. From all of this, a detailed report is generated that reveals the true condition of the oil.
Oil analysis is a great idea for fleets and trucks that hold a lot of oil. But most consumers would have a hard time justifying the cost. Having an oil sample analyzed typically costs $12 to $20 for the lab work and report. Most quick lube shops charge $16.95 to $19.95 for an oil change. So why spend your money on a report that will probably tell you your oil needs changing? Just change the oil every 3,000 miles and don't worry about it.
Regular oil changes for preventative maintenance are cheap insurance against engine wear, and will always save you money in the long run if you keep a car for more than three or four years. It's very uncommon to see an engine that has been well maintained with regular oil changes develop major bearing, ring, cam or valve problems under 100,000 miles.
WHAT ABOUT THE OIL FILTER?
To reduce the costs of vehicle ownership and maintenance, many car makers say the oil filter only needs to be replaced at every other oil change. Most mechanics will tell you this is false economy.
The oil filters on most engines today have been downsized to save weight, cost and space. The "standard" quart-sized filter that was once common on most engines has been replaced by a pint-sized (or smaller) filter. You don't have to be a rocket scientist to figure out that a smaller filter has less total filtering capacity. Even so, the little filters should be adequate for a 3,000 mile oil change intervals -- but may run out of capacity long before a second oil change at 6,000 or 15,000 miles.
Replacing the oil filter every time the oil is changed, therefore, is highly recommended.
An engine's main line of defense against abrasion and the premature wear it causes is the oil filter. The filter's job is to remove solid contaminants such as dirt, carbon and metal particles from the oil before they can damage bearing, journal and cylinder wall surfaces in the engine. The more dirt and other contaminants the filter can trap and hold, the better.
In today's engines, all the oil that's picked up by the oil pump is routed through the filter before it goes to the crankshaft bearings, cam bearings and valve train. This is called "full-flow" filtration. It's an efficient way of removing contaminants, and it assures only filtered oil is supplied to the engine. In time, though, accumulated dirt and debris trapped by the filter begin to obstruct the flow of oil. The filter should be changed before it reaches this point, which is why the filter needs to be replaced when the oil is changed.
If you wait too long to change the filter, there's a danger that it might become plugged. To prevent this from causing a catastrophic engine failure due to loss of lubrication, oil filters have a built-in safety device called a "bypass valve." When the pressure drop across the filter exceeds a predetermined value (which varies depending on the engine application), the bypass valve opens so oil can continue to flow to the engine. But this allows unfiltered oil to enter the engine. Any contaminants that find their way into the crankcase will be pumped through the engine and accelerate wear.
FILTER REPLACEMENT
If you do your own oil changes, make sure you get the correct filter for your engine. Follow the filter manufacturer's listings in its catalog. Many filters that look the same on the outside have different internal valving. Many overhead cam engines, for example, require an "anti-drainback" valve in the filter to prevent oil from draining out of the filter when the engine is shut off. This allows oil pressure to reach critical engine parts more quickly when the engine is restarted. Filters that are mounted sideways on the engine typically require an anti-drainback valve.
CAUTION: The threads on a spin-on filter must also be the correct diameter and thread pitch (SAE or metric) for your engine. If you install a filter with SAE threads on an engine that requires metric threads (or vice versa), you can damage the threads that hold the oil filter in place. Mismatched threads can also allow the filter to work loose, which causes a sudden loss of oil pressure that may ruin your engine!
CHANGING YOUR OWN OIL
Some people say it's best to change the oil when the oil is hot (like right after driving), while others say it makes no difference. CAUTION: Hot oil is thinner and runs out faster but can also burn you if you're not careful. In any event, avoid unnecessary skin contact with oil because oil is a suspected carcinogen (causes cancer).
Changing the oil when it is cold may take a bit longer because the oil will drain more slowly from the engine, but there's no danger of being burned. Also, most of the oil will have drained down into the oil pan when the engine has sat for a period of time, which means you'll actually get a little more of the old oil out of the engine than if you attempt to drain it while it is still hot.
Used motor oil should be disposed of properly. The Environmental Protection Agency does not consider used motor oil to be a hazardous chemical, but it can foul ground water and does contain traces of lead. The best way to dispose of used motor oil is to take it to a service station, quick lube shop, parts store or other facility for recycling. Your old oil will either be rerefined into other lubricants or petroleum products, or burned as fuel.
Do not dump used motor oil on the ground, down a drain, into a storm sewer or place it in the trash. Many landfills will not accept used motor oil even if it is in a sealed container because it will eventually leak out into the ground. If you can't find an environmentally-acceptable way to dispose of the stuff, maybe you shouldn't be changing your own oil. Service facilities that do oil changes all have storage tanks and recycling programs to dispose of used oil.
Question: What type of motor oil is best for my engine?
Answer: The type specified by the vehicle manufacturer in your owner's manual. For most passenger car and light truck gasoline engines today, it's any oil that meets the American Petroleum Institutes "SH" rating.
As for the viscosity of oil to use, most new engines today require a multiviscosity 5W-30 oil for all-round driving. The lighter 5W-30 oils contain friction reducing additives that help improve fuel economy, and also allow the oil to quickly reach critical upper valvetrain components when a cold engine is first started. Most engine wear occurs immediately after a cold start, so it's important to have oil that is thin enough to circulate easily -- especially at cold temperatures.
For older engines and ones that are driven at sustained highways speeds during hot weather, 10W-30 or 10W-40 is a good choice. Heavier multiviscosity oils such as 20W-40 are for high rpm, high-load applications primarily and are not recommended for cold weather driving.
Straight weight 30W and 40W oils aren't very popular anymore, but some diehards insist on using them. They say the thicker oil holds up better under high temperature (which it does), increases oil pressure and reduces oil consumption in high mileage engines. But straight 30W and 40W oils are too thick for cold weather and may make an engine hard to start. They may also be too thick to provide adequate start-up lubrication to critical upper valvetrain components during cold weather. So switching to a straight 20W oil would be necessary for cold weather driving. Straight 10W oil can also improve cold starting, but is very thin and should only be used in sub-zero climates. A multiviscosity 10W-30 or 10W-40 will provide the same cold starting benefits of a 10W oil and the high temperature protection of a 30W or 40W oil.
SYNTHETIC OILS
For the ultimate in high temperature protection, durability and all-round performance, synthetic oils are the way to go. Unfortunately, most synthetic oils cost up to three times as much as ordinary petroleum-based oils. They cost more because synthetics are manmade rather than refined from petroleum. But this improves their performance in virtually every aspect:
CAUTION: For vehicles under warranty, extending the normal change interval is not recommended because failing to follow the OEM's maintenance schedule can void your warranty.
Synthetics are available in the same grades as ordinary motor oils (5W-30, 5W-20 and 10W-30) as well as "extended" grades such as 15W-50 and even 5W-50.
There are also lower-cost synthetic "blends" that combine synthetic and petroleum-based oils in the same container. But you can do your own blend to save money by simply substituting a quart or two of synthetic oil for conventional oil when you change oil. Synthetics are compatible with conventional motor oils.
Who should use a synthetic oil? The premium-priced oil is best for:
Question: My engine uses oil. I'm always adding oil so why should I ever change it?
Answer: You should still change your oil and filter periodically to get rid of contaminants and sludge that build up in the crankcase. Just because your engine uses oil doesn't mean the oil that's in it stays clean. It doesn't. It gunks up just as fast as the oil in an engine that doesn't burn oil. In fact, it probably gunks up faster because of increased blow by due to the worn pistons and rings.
If you never change the oil, sooner or later the filter will plug up. And once that happens, you've lost all protection against dirt and abrasives. Before long, the bearings will become worn and you'll hear the rods knocking. Keep driving and something will eventually let go. End of engine. End of story.
My engine uses about a quart of oil every 1,000 miles. Should I be concerned?
Answer:
Not if you plan to sell or trade your vehicle soon. An engine that uses a quart of oil every 1,000 miles is starting to show the effects of wear. The amount of oil it is using is still acceptable, but it will gradually increase as the miles add up. When it reaches the point where it's using a quart every 500 miles or less, it's time for an overhaul.
Oil consumption depends primarily on two things: the valve guides and piston rings. If the valve guides are worn, or if there's too much clearance between the valve stems and guides, or if the valve guide seals are worn, cracked, missing, broken or improperly installed, the engine will suck oil down the guides and into the cylinders. The engine may still have good compression, but will use a lot of oil.
An oil consumption problem caused by worn valve guides can usually be cured by a valve job. Knurling or replacing the guides or boring out the guides and installing valves with oversized stems will stop the loss of oil.
Oil can also get past the rings if the rings or cylinders are badly worn or damaged, if the cylinders were not honed properly when the engine was built (or rebuilt), or if the rings were installed improperly.
When a newly-built engine is first started, the rings require a certain amount of time to "seat" or break-in. If the rings fail to seat properly, the engine will use oil. This may be the case if somebody applied the wrong finish to the cylinders, failed to clean and lubricate the cylinders properly before the engine was fired up, or didn't use the proper break-in procedure.
If the rings and/or cylinders are at fault, the engine will have lower than normal compression readings.
In some instances, worn rod bearings, excessive bearing clearances and/or excessive oil pressure can splash too much oil on the cylinders causing oil to get past the rings.
The cure for worn rings and cylinders is to overhaul the engine block. The cylinders have to be refinished and new rings installed to regain good oil control.
Question:
My engine is leaking oil past the valve cover gaskets. I've tried tightening down the valve cover bolts, but it doesn't seem to help. What should I do?
Answer:
Bite the bullet and buy a new set of valve cover gaskets. Most cork valve cover gaskets usually cost less than $20 and are fairly easy to install on many engines. You may have to disconnect and remove some plumbing or other accessories to get to the valve covers, but on many engines the job is usually within the capabilities of a do-it-yourselfer. If the valve covers are buried or access is difficult, then let a professional replace the gaskets for you.
Tightening the valve cover bolts or screws will rarely stop an oil leak because the gasket is usually cracked, crushed or has lost its natural elasticity. Cork gaskets only last about four to six years before they age harden, become brittle and start to leak. Molded silicone rubber gaskets, on the other hand, (which are used on many late model domestic and import engines) often last the life of the engine. But molded rubber gaskets are a lot more expensive than die cut cork gaskets. That's why cork gaskets have long been used by the vehicle manufacturers.
Some engines do not have gaskets, but instead use a rubbery-glue called "RTV silicone sealer (the "RTV" stands for Room Temperature Vulcanizing). If this is the case, you can remove the valve cover, scrape off all the old RTV, and either apply a fresh bead of RTV silicone sealer to the valve cover flange or head mating surface or install a conventional gasket.
CAUTION: Do not let any pieces of rubber or debris fall into the engine. Also, if you decide to use RTV sealer and your engine has an oxygen sensor (which almost all 1981 and later engines do), make sure the RTV sealer is the "low volatile" variety that is approved for use with oxygen sensors. Some types of RTV give off silicone vapor that can be sucked through the crankcase and contaminate the oxygen sensor.
Question: Is it better to maintain my engine's oil level at the full mark or wait until it reaches the "add" mark to add oil?
Answer: Most vehicle manufacturers say it's okay to wait until the level reaches the add mark to add oil. The add mark is typically one quart below the full mark on the dip stick.Considering that the crankcase capacity on most passenger cars today is only four quarts, running the engine 25% low on oil (one quart) may not be wise. Here's why.
Oil not only lubricates the engine's internal parts, but also helps cool the bearings. The total amount of oil in the engine, therefore, serves as a heat sink to help control heat. Under normal driving conditions, running a quart low probably doesn't make much difference in terms of bearing temperature or overall engine lubrication. But during extremely hot weather, when driving at sustained highway speeds and/or when towing a trailer, running a quart low may increase the risk of accelerated engine wear and/or damage.
The best advice, therefore, is to add oil whenever the dipstick reads low. Don't wait until it is down a full quart. If it needs half a quart, add half a quart to bring it back up to the full mark.
CAUTION: Do not overfill the engine. Adding too much oil can overfill the crankcase. As the crankshaft spins around, it can whip the oil into foam if the level is too high. This, in turn, can cause a drop in oil pressure and loss of lubrication to critical engine parts. Also, too much oil may cause leaks as the extra oil is forced past seals and gaskets.
Follow your vehicle manufacturer's guidelines for the type and viscosity of oil to use in your engine.
Question:
How often should I change my oil?
Answer:
Most vehicle manufacturers recommend changing the oil once a year or every 7,500 miles in passenger car and light truck gasoline engines. For diesel engines and turbocharged gasoline engines, the usual recommendation is every 3,000 miles or six months.
If you read the fine print, however, you'll discover that the once a year, 7,500 mile oil change is for vehicles that are driven under ideal circumstances. What most of us think of as "normal" driving is actually "severe service" driving. This includes frequent short trips (less than 10 miles, especially during cold weather), stop-and-go city traffic driving, driving in dusty conditions (gravel roads, etc.), and driving at sustained highway speeds during hot weather. For this type of driving, which is actually "severe service: driving, the recommendation is to change the oil every 3,000 miles or six months.
For maximum protection, most oil companies say to change the oil every 3,000 miles or three to six months regardless of what type of driving you do.
A new engine with little or no wear can probably get by on 7,500 mile oil changes. But as an engine accumulates miles, blow by increases. This dumps more unburned fuel into the crankcase which dilutes the oil. This causes the oil to break down. So if the oil isn't changed often enough, you can end up with accelerated wear and all the engine problems that come with it (loss of performance and fuel economy, and increased emissions and oil consumption).
OIL ANALYSIS
Truck fleets often monitor the condition of the oil in their vehicles by having samples analyzed periodically. Oil samples are sent to a laboratory that then analyzes the oil's viscosity and acid content. Oil is then burned in a device called a spectrometer that reveals various impurities in the oil. From all of this, a detailed report is generated that reveals the true condition of the oil.
Oil analysis is a great idea for fleets and trucks that hold a lot of oil. But most consumers would have a hard time justifying the cost. Having an oil sample analyzed typically costs $12 to $20 for the lab work and report. Most quick lube shops charge $16.95 to $19.95 for an oil change. So why spend your money on a report that will probably tell you your oil needs changing? Just change the oil every 3,000 miles and don't worry about it.
Regular oil changes for preventative maintenance are cheap insurance against engine wear, and will always save you money in the long run if you keep a car for more than three or four years. It's very uncommon to see an engine that has been well maintained with regular oil changes develop major bearing, ring, cam or valve problems under 100,000 miles.
WHAT ABOUT THE OIL FILTER?
To reduce the costs of vehicle ownership and maintenance, many car makers say the oil filter only needs to be replaced at every other oil change. Most mechanics will tell you this is false economy.
The oil filters on most engines today have been downsized to save weight, cost and space. The "standard" quart-sized filter that was once common on most engines has been replaced by a pint-sized (or smaller) filter. You don't have to be a rocket scientist to figure out that a smaller filter has less total filtering capacity. Even so, the little filters should be adequate for a 3,000 mile oil change intervals -- but may run out of capacity long before a second oil change at 6,000 or 15,000 miles.
Replacing the oil filter every time the oil is changed, therefore, is highly recommended.
An engine's main line of defense against abrasion and the premature wear it causes is the oil filter. The filter's job is to remove solid contaminants such as dirt, carbon and metal particles from the oil before they can damage bearing, journal and cylinder wall surfaces in the engine. The more dirt and other contaminants the filter can trap and hold, the better.
In today's engines, all the oil that's picked up by the oil pump is routed through the filter before it goes to the crankshaft bearings, cam bearings and valve train. This is called "full-flow" filtration. It's an efficient way of removing contaminants, and it assures only filtered oil is supplied to the engine. In time, though, accumulated dirt and debris trapped by the filter begin to obstruct the flow of oil. The filter should be changed before it reaches this point, which is why the filter needs to be replaced when the oil is changed.
If you wait too long to change the filter, there's a danger that it might become plugged. To prevent this from causing a catastrophic engine failure due to loss of lubrication, oil filters have a built-in safety device called a "bypass valve." When the pressure drop across the filter exceeds a predetermined value (which varies depending on the engine application), the bypass valve opens so oil can continue to flow to the engine. But this allows unfiltered oil to enter the engine. Any contaminants that find their way into the crankcase will be pumped through the engine and accelerate wear.
FILTER REPLACEMENT
If you do your own oil changes, make sure you get the correct filter for your engine. Follow the filter manufacturer's listings in its catalog. Many filters that look the same on the outside have different internal valving. Many overhead cam engines, for example, require an "anti-drainback" valve in the filter to prevent oil from draining out of the filter when the engine is shut off. This allows oil pressure to reach critical engine parts more quickly when the engine is restarted. Filters that are mounted sideways on the engine typically require an anti-drainback valve.
CAUTION: The threads on a spin-on filter must also be the correct diameter and thread pitch (SAE or metric) for your engine. If you install a filter with SAE threads on an engine that requires metric threads (or vice versa), you can damage the threads that hold the oil filter in place. Mismatched threads can also allow the filter to work loose, which causes a sudden loss of oil pressure that may ruin your engine!
CHANGING YOUR OWN OIL
Some people say it's best to change the oil when the oil is hot (like right after driving), while others say it makes no difference. CAUTION: Hot oil is thinner and runs out faster but can also burn you if you're not careful. In any event, avoid unnecessary skin contact with oil because oil is a suspected carcinogen (causes cancer).
Changing the oil when it is cold may take a bit longer because the oil will drain more slowly from the engine, but there's no danger of being burned. Also, most of the oil will have drained down into the oil pan when the engine has sat for a period of time, which means you'll actually get a little more of the old oil out of the engine than if you attempt to drain it while it is still hot.
Used motor oil should be disposed of properly. The Environmental Protection Agency does not consider used motor oil to be a hazardous chemical, but it can foul ground water and does contain traces of lead. The best way to dispose of used motor oil is to take it to a service station, quick lube shop, parts store or other facility for recycling. Your old oil will either be rerefined into other lubricants or petroleum products, or burned as fuel.
Do not dump used motor oil on the ground, down a drain, into a storm sewer or place it in the trash. Many landfills will not accept used motor oil even if it is in a sealed container because it will eventually leak out into the ground. If you can't find an environmentally-acceptable way to dispose of the stuff, maybe you shouldn't be changing your own oil. Service facilities that do oil changes all have storage tanks and recycling programs to dispose of used oil.
Question: What type of motor oil is best for my engine?
Answer: The type specified by the vehicle manufacturer in your owner's manual. For most passenger car and light truck gasoline engines today, it's any oil that meets the American Petroleum Institutes "SH" rating.
As for the viscosity of oil to use, most new engines today require a multiviscosity 5W-30 oil for all-round driving. The lighter 5W-30 oils contain friction reducing additives that help improve fuel economy, and also allow the oil to quickly reach critical upper valvetrain components when a cold engine is first started. Most engine wear occurs immediately after a cold start, so it's important to have oil that is thin enough to circulate easily -- especially at cold temperatures.
For older engines and ones that are driven at sustained highways speeds during hot weather, 10W-30 or 10W-40 is a good choice. Heavier multiviscosity oils such as 20W-40 are for high rpm, high-load applications primarily and are not recommended for cold weather driving.
Straight weight 30W and 40W oils aren't very popular anymore, but some diehards insist on using them. They say the thicker oil holds up better under high temperature (which it does), increases oil pressure and reduces oil consumption in high mileage engines. But straight 30W and 40W oils are too thick for cold weather and may make an engine hard to start. They may also be too thick to provide adequate start-up lubrication to critical upper valvetrain components during cold weather. So switching to a straight 20W oil would be necessary for cold weather driving. Straight 10W oil can also improve cold starting, but is very thin and should only be used in sub-zero climates. A multiviscosity 10W-30 or 10W-40 will provide the same cold starting benefits of a 10W oil and the high temperature protection of a 30W or 40W oil.
SYNTHETIC OILS
For the ultimate in high temperature protection, durability and all-round performance, synthetic oils are the way to go. Unfortunately, most synthetic oils cost up to three times as much as ordinary petroleum-based oils. They cost more because synthetics are manmade rather than refined from petroleum. But this improves their performance in virtually every aspect:
- Superior temperature resistance. Synthetics can safely handle higher operating temperatures without oxidizing (burning) or breaking down. The upper limit for most mineral based oils is about 250 to 300 degrees F. Synthetics can take up to 450 degrees F. or higher. This makes synthetics well-suited for turbo applications as well as high rpm and high output engine applications.
- Better low temperature performance. Synthetics flow freely at subzero temperatures, pouring easily at -40 or -50 degrees F. where ordinary oils turn to molasses. This makes for easier cold starts and provides faster upper valvetrain lubrication during the first critical moments when most engine wear occurs.
- Better engine performance. Synthetics tend to be more slippery than their petroleum-based counterparts, which improves fuel economy, cuts frictional horsepower losses and helps the engine run cooler. The difference isn't great, but it can make a noticeable difference.
- Longer oil change intervals. Because synthetics resist oxidation and viscosity breakdown better than ordinary motor oils, some suppliers say oil change intervals can be safely extended -- in some cases stretched to as much as 25,000 miles. Such claims are justified by the fact that synthetics don't break down or sludge up as fast as ordinary mineral-based oils do in use.
CAUTION: For vehicles under warranty, extending the normal change interval is not recommended because failing to follow the OEM's maintenance schedule can void your warranty.
Synthetics are available in the same grades as ordinary motor oils (5W-30, 5W-20 and 10W-30) as well as "extended" grades such as 15W-50 and even 5W-50.
There are also lower-cost synthetic "blends" that combine synthetic and petroleum-based oils in the same container. But you can do your own blend to save money by simply substituting a quart or two of synthetic oil for conventional oil when you change oil. Synthetics are compatible with conventional motor oils.
Who should use a synthetic oil? The premium-priced oil is best for:
- Turbocharged or supercharged engines
- Performance or high output engines
- Vehicles used for towing (especially during hot weather)
- Vehicles that are operated in extremely cold or hot climates
- Anyone who wants the ultimate in lubrication and protection
Question: My engine uses oil. I'm always adding oil so why should I ever change it?
Answer: You should still change your oil and filter periodically to get rid of contaminants and sludge that build up in the crankcase. Just because your engine uses oil doesn't mean the oil that's in it stays clean. It doesn't. It gunks up just as fast as the oil in an engine that doesn't burn oil. In fact, it probably gunks up faster because of increased blow by due to the worn pistons and rings.
If you never change the oil, sooner or later the filter will plug up. And once that happens, you've lost all protection against dirt and abrasives. Before long, the bearings will become worn and you'll hear the rods knocking. Keep driving and something will eventually let go. End of engine. End of story.
Under hood Maintenance: Drive Belts
Inspect and Adjust Engine Accessory Drive Belts
Many engine accessories--including the alternator, fan, and coolant pump--are operated by drive belts. If these belts break or slip, the components they drive will fail to work. The belt that drives the fan also drives the coolant pump. If it breaks, coolant and air circulation stop, and the engine overheats at once.
Drive belts should be inspected for a potential problem anytime you have the hood of a customer's car up. A quick inspection can locate a problem and save your customer a major problem.
CAUTION: Never try to adjust or inspect belts with the engine running. Make sure no one is in the car who could start the engine during belt inspection.
To inspect the belts, grab the belt in your hand and twist it so you can see the underside of the "V" shape on V-type belts, or the ribs on a serpentine-type belt. Use a trouble or flashlight so you can make a close inspection. Cracks indicate the belt is getting ready to fail. Oil-soaked belts can slip and not rotate the component they are driving fast enough. Glazed belts have a shiny appearance; this occurs when a belt is not tight enough and the slipping polishes its surface. Torn or split belts have major damage and must be replaced immediately.
Before adjusting any drive belt, always check the service manual for specific instructions. Find the longest span in the belt and push on it as shown below. It should move in about half an inch per foot of free span. If it moves more than this, the belt is too loose. If it moves less, it is too tight.
A belt tension gauge can also be used for testing belt tension. These gauges are operated differently, so follow the instructions on the tool. Basically, you attach the gauge to the longest span of the belt. Then you pull on the belt and measure the tension. Specifications are available in the shop service manual to compare against your reading.
Most belts are adjusted by loosening the support for the alternator and moving it back and forth to tighten or loosen the belt. Other systems use an idler pulley for the adjustment. First loosen the adjustment fastener on the slotted alternator support. Wedge a prybar between a strong part of the engine and the alternator. Pull on the pry bar to move the alternator housing in a direction to tighten the belt. Tighten the adjustment fastener. Recheck the adjustment by measuring the belt as explained earlier.
Remove and Replace an Accessory Drive Belt
When you have determined that a drive belt is defective and needs to be replaced, you should have the replacement belt on hand. Loosen the adjustment fastener on the alternator or idler pulley. Push the alternator or idler pulley inward to loosen the belt. Pull the old drive belt off the pulleys.
Place the new and old belt side by side on the work bench to make a comparison. The belt width and length of the new belt must be the same. If you find a difference, check to see that you have not gotten the wrong belt. A belt that is too long to be adjusted properly will slip. A belt that is too short will not fit over the pulleys. A belt with the incorrect width or V shape could be thrown off when the engine is running.
Install the correct belt over the pulleys. Adjust the belt to the proper tension as described previously. Start the engine and observe the belt in operation. Stop the engine and recheck the tension.
SERVICE TIP: There is an old trick tow truck drivers use when responding to cars that are disabled because of a broken drive belt. They carry packages of women's pantyhose. They wind them around the pulleys and then tie them in a knot. The pantyhose will work as a belt for a short distance to get the car to a service facility.
Question:
How do I know if a V-belt needs to be replaced?
Answer:
One way to find out is to examine the belt. If a V-belt is full of tiny cracks, frayed, has pieces of rubber missing, is peeling or otherwise damaged, it needs to be replaced -- NOW. Also, if a belt is oil soaked or "glazed" (hard shiny appearance on the sides of the belt) it also needs to be replaced. Either of these two conditions can cause the belt to run hot, which can weaken it and increase the danger of it breaking.
Unfortunately, a visual inspection alone isn't a sure-fire method of determining the true condition of a belt because internal wear that you can't see is just as important as external wear that you can see. All belts are reinforced with cords. The cords are what give the belt its strength and keep it from stretching or breaking. But as a belt ages, the constant flexing, heat and strain weakens the cords. Eventually the cords reach a point where failure can happen suddenly and unexpectedly. The belt may still look good as new on the outside, but be on the verge of snapping internally because the cords have lost their strength.
So the other factors that need to be considered when judging the condition of a V-belt include the belt's mileage and age. A V-belt that's more than three or four years old and has more than 40,000 or 50,000 miles on it may be a belt that is nearing the end of its useful service life. For this reason, you might be well advised to replace a high mileage belt even if it still looks okay.
Question:
Is it necessary to replace belts periodically?
Answer:
Yes. Although the auto makers don't usually specify a replacement interval for V-belts or serpentine (flat, multi-ribbed) belts, most belt manufacturers do recommend periodic replacement for preventative maintenance. Here's why: the incidence of belt failure rises sharply in the fourth year of service for the typical V-belt, and the fifth year for serpentine belts.
What's more, eight out of ten V-belt failures and ten out of ten serpentine belt failures end up causing a breakdown! That's because belts have the uncanny knack of always picking the worst possible moment to fail -- like when you're heading out of town on that long-awaited fishing trip, when you're hurrying to pick up a hot date who told you NOT to be late, or when you're giving your dear mother-in-law a ride to church.
A broken belt is always bad news because when it snaps, all drive power to whatever it turns is lost. That means the water pump quits circulating coolant through the engine, the alternator quits producing amps, the power steering pump ceases to assist steering, and the air conditioner quits cooling. Many newer vehicles have a single serpentine belt that drives all of the engine's accessories, so when it fails everything stops working.
The good news is that replacing the belts periodically can go a long way towards minimizing the risk of a breakdown caused by belt failure. After all, it's a lot easier to replace a belt at your convenience than having the belt fail unexpectedly Heavens knows where.
For optimum protection, most experts recommend replacing V-belts every three to four years, or every 36,000 to 48,000 miles. A recommended replacement interval for serpentine belts would be every four or five years, or 50,000 miles.
BELT LIFE
The service life of a V-belt depends on mileage as well as load, tension and heat. Every time a belt passes around a pulley, it bends and flexes. This produces heat which age hardens the rubber over time. The wear process can be greatly accelerated if the belt is loose and slips because any added friction between belt and pulley makes the belt run even hotter. This can cause glazing on the faces of the belt and cause it to slip even more. So one of the most important factors that affects belt life is making sure it is properly tensioned when it is installed and that the proper tension is maintained throughout its service life.
Symptoms that may be the result of improper belt tension include:
BELT REPLACEMENT
Replacement V-belts must be the same length and width as the original. A belt that's too long or too short may not allow enough adjustment for proper tension. A belt that's too wide or too narrow will not ride at the right depth in the pulley grooves.
CAUTION: When installing a new belt, do not attempt to "stretch" it over pulleys. Doing so can break the internal cords causing the belt to fail. Always loosen the pulleys so there is adequate clearance to slip the belt over the pulleys.
Once the belt has been installed on the pulleys, a belt gauge should be used to adjust belt tension to factory specifications. The old rule of thumb of allowing 1/2 inch of "give" between the furthest pulleys is not a very accurate guide for today's engines. So follow the manufacturer's recommendations for belt tension.
Once tension has been adjusted, it should be rechecked and readjusted (if necessary) after a short break-in period (say after 500 to 1,000 miles of driving). It should then be checked twice a year or every 5,000 or 6,000 miles thereafter.
On vehicles with a single serpentine belt, tension is usually self-adjusted automatically via a spring loaded tensioner. No additional adjustment is necessary.
If your engine has been eating or twisting belts, misaligned pulleys may be your problem. Alignment can be checked with a straightedge. If a pulley is bent or not in the same plane as the rest, the problem should be corrected otherwise the "bad" pulley will continue to ruin belts.
Many engine accessories--including the alternator, fan, and coolant pump--are operated by drive belts. If these belts break or slip, the components they drive will fail to work. The belt that drives the fan also drives the coolant pump. If it breaks, coolant and air circulation stop, and the engine overheats at once.
Drive belts should be inspected for a potential problem anytime you have the hood of a customer's car up. A quick inspection can locate a problem and save your customer a major problem.
CAUTION: Never try to adjust or inspect belts with the engine running. Make sure no one is in the car who could start the engine during belt inspection.
To inspect the belts, grab the belt in your hand and twist it so you can see the underside of the "V" shape on V-type belts, or the ribs on a serpentine-type belt. Use a trouble or flashlight so you can make a close inspection. Cracks indicate the belt is getting ready to fail. Oil-soaked belts can slip and not rotate the component they are driving fast enough. Glazed belts have a shiny appearance; this occurs when a belt is not tight enough and the slipping polishes its surface. Torn or split belts have major damage and must be replaced immediately.
Before adjusting any drive belt, always check the service manual for specific instructions. Find the longest span in the belt and push on it as shown below. It should move in about half an inch per foot of free span. If it moves more than this, the belt is too loose. If it moves less, it is too tight.
A belt tension gauge can also be used for testing belt tension. These gauges are operated differently, so follow the instructions on the tool. Basically, you attach the gauge to the longest span of the belt. Then you pull on the belt and measure the tension. Specifications are available in the shop service manual to compare against your reading.
Most belts are adjusted by loosening the support for the alternator and moving it back and forth to tighten or loosen the belt. Other systems use an idler pulley for the adjustment. First loosen the adjustment fastener on the slotted alternator support. Wedge a prybar between a strong part of the engine and the alternator. Pull on the pry bar to move the alternator housing in a direction to tighten the belt. Tighten the adjustment fastener. Recheck the adjustment by measuring the belt as explained earlier.
Remove and Replace an Accessory Drive Belt
When you have determined that a drive belt is defective and needs to be replaced, you should have the replacement belt on hand. Loosen the adjustment fastener on the alternator or idler pulley. Push the alternator or idler pulley inward to loosen the belt. Pull the old drive belt off the pulleys.
Place the new and old belt side by side on the work bench to make a comparison. The belt width and length of the new belt must be the same. If you find a difference, check to see that you have not gotten the wrong belt. A belt that is too long to be adjusted properly will slip. A belt that is too short will not fit over the pulleys. A belt with the incorrect width or V shape could be thrown off when the engine is running.
Install the correct belt over the pulleys. Adjust the belt to the proper tension as described previously. Start the engine and observe the belt in operation. Stop the engine and recheck the tension.
SERVICE TIP: There is an old trick tow truck drivers use when responding to cars that are disabled because of a broken drive belt. They carry packages of women's pantyhose. They wind them around the pulleys and then tie them in a knot. The pantyhose will work as a belt for a short distance to get the car to a service facility.
Question:
How do I know if a V-belt needs to be replaced?
Answer:
One way to find out is to examine the belt. If a V-belt is full of tiny cracks, frayed, has pieces of rubber missing, is peeling or otherwise damaged, it needs to be replaced -- NOW. Also, if a belt is oil soaked or "glazed" (hard shiny appearance on the sides of the belt) it also needs to be replaced. Either of these two conditions can cause the belt to run hot, which can weaken it and increase the danger of it breaking.
Unfortunately, a visual inspection alone isn't a sure-fire method of determining the true condition of a belt because internal wear that you can't see is just as important as external wear that you can see. All belts are reinforced with cords. The cords are what give the belt its strength and keep it from stretching or breaking. But as a belt ages, the constant flexing, heat and strain weakens the cords. Eventually the cords reach a point where failure can happen suddenly and unexpectedly. The belt may still look good as new on the outside, but be on the verge of snapping internally because the cords have lost their strength.
So the other factors that need to be considered when judging the condition of a V-belt include the belt's mileage and age. A V-belt that's more than three or four years old and has more than 40,000 or 50,000 miles on it may be a belt that is nearing the end of its useful service life. For this reason, you might be well advised to replace a high mileage belt even if it still looks okay.
Question:
Is it necessary to replace belts periodically?
Answer:
Yes. Although the auto makers don't usually specify a replacement interval for V-belts or serpentine (flat, multi-ribbed) belts, most belt manufacturers do recommend periodic replacement for preventative maintenance. Here's why: the incidence of belt failure rises sharply in the fourth year of service for the typical V-belt, and the fifth year for serpentine belts.
What's more, eight out of ten V-belt failures and ten out of ten serpentine belt failures end up causing a breakdown! That's because belts have the uncanny knack of always picking the worst possible moment to fail -- like when you're heading out of town on that long-awaited fishing trip, when you're hurrying to pick up a hot date who told you NOT to be late, or when you're giving your dear mother-in-law a ride to church.
A broken belt is always bad news because when it snaps, all drive power to whatever it turns is lost. That means the water pump quits circulating coolant through the engine, the alternator quits producing amps, the power steering pump ceases to assist steering, and the air conditioner quits cooling. Many newer vehicles have a single serpentine belt that drives all of the engine's accessories, so when it fails everything stops working.
The good news is that replacing the belts periodically can go a long way towards minimizing the risk of a breakdown caused by belt failure. After all, it's a lot easier to replace a belt at your convenience than having the belt fail unexpectedly Heavens knows where.
For optimum protection, most experts recommend replacing V-belts every three to four years, or every 36,000 to 48,000 miles. A recommended replacement interval for serpentine belts would be every four or five years, or 50,000 miles.
BELT LIFE
The service life of a V-belt depends on mileage as well as load, tension and heat. Every time a belt passes around a pulley, it bends and flexes. This produces heat which age hardens the rubber over time. The wear process can be greatly accelerated if the belt is loose and slips because any added friction between belt and pulley makes the belt run even hotter. This can cause glazing on the faces of the belt and cause it to slip even more. So one of the most important factors that affects belt life is making sure it is properly tensioned when it is installed and that the proper tension is maintained throughout its service life.
Symptoms that may be the result of improper belt tension include:
- Belt squeal, especially on the fan, A/C compressor or power steering drives.
A battery that keeps running down (due to belt slippage). - Excessive sidewall wear on a V-belt that causes it to ride lower than normal in the pulley grooves.
- Severe cracking along the underside of a V-belt.
- Noisy alternator, power steering pump, air pump, A/C compressor or water pump bearings (from excessive belt tension).
BELT REPLACEMENT
Replacement V-belts must be the same length and width as the original. A belt that's too long or too short may not allow enough adjustment for proper tension. A belt that's too wide or too narrow will not ride at the right depth in the pulley grooves.
CAUTION: When installing a new belt, do not attempt to "stretch" it over pulleys. Doing so can break the internal cords causing the belt to fail. Always loosen the pulleys so there is adequate clearance to slip the belt over the pulleys.
Once the belt has been installed on the pulleys, a belt gauge should be used to adjust belt tension to factory specifications. The old rule of thumb of allowing 1/2 inch of "give" between the furthest pulleys is not a very accurate guide for today's engines. So follow the manufacturer's recommendations for belt tension.
Once tension has been adjusted, it should be rechecked and readjusted (if necessary) after a short break-in period (say after 500 to 1,000 miles of driving). It should then be checked twice a year or every 5,000 or 6,000 miles thereafter.
On vehicles with a single serpentine belt, tension is usually self-adjusted automatically via a spring loaded tensioner. No additional adjustment is necessary.
If your engine has been eating or twisting belts, misaligned pulleys may be your problem. Alignment can be checked with a straightedge. If a pulley is bent or not in the same plane as the rest, the problem should be corrected otherwise the "bad" pulley will continue to ruin belts.
Under hood Maintenance: Coolant
Question: How often should I change my antifreeze?
Answer: For "ordinary" antifreeze, the vehicle manufacturers generally recommend coolant changes every two to three years or 30,000 miles. Others say it's not a bad idea to change the coolant every year for maximum corrosion protection -- especially in vehicles that have aluminum heads, blocks or radiators. But such recommendations may soon be obsolete. Several antifreeze suppliers have just recently introduced "long life" antifreeze formulations that claim to provide protection for four years or 50,000 miles.
General Motors just introduced a new five year, 100,000 mile antifreeze in its 1996 cars and light trucks. The new coolant is called "Dex-Cool" and is dyed orange to distinguish it from ordinary antifreeze (which is green).
CAUTION: These new long life coolants provide extended life only when used in a clean system mixed with water. If mixed with ordinary antifreeze and/or old coolant in a system, the corrosion protection is reduced to that of normal antifreeze (2 to 3 years and 30,000 miles).
CORROSION INHIBITORS
The life of the antifreeze depends on it's ability to inhibit corrosion. Silicates, phosphates and/or borates are used as corrosion inhibitors to keep the solution alkaline. As long as the antifreeze remains so, corrosion is held in check and there's no need to change the coolant. But as the corrosion inhibiting chemicals are used up over time, electrolytic corrosion starts to eat away at the metal inside the engine and radiator. Aluminum is especially vulnerable to corrosion and can turn to Swiss cheese rather quickly when conditions are right. Solder bloom can also form in copper\brass radiators causing leaks and restrictions. So changing the coolant periodically as preventative maintenance is a good way to prevent costly repairs.
The basic idea is to change the coolant before the corrosion inhibitors reach dangerously low levels. Following the OEM change recommendations is usually good enough to keep corrosion in check, but it may not always be the case. That's why more frequent changes may be recommended to minimize the risk of corrosion in bimetal engines and aluminum radiators.
CHECKING THE ANTIFREEZE
One way to find out if it's time to change the antifreeze is to test it. Several suppliers make special antifreeze test strips that react to the pH (alkalinity) of the coolant and change color. If the test strip indicates a marginal or bad condition, the coolant should be changed.
CHANGING THE COOLANT
Reverse flushing is the best way to change the coolant because draining alone can leave as much as 30 to 50% of the old coolant in the engine block. Reverse flushing also helps dislodge deposits and scale which can interfere with good heat transfer.
The concentration of antifreeze in the coolant also needs to be checked prior to the onset of cold weather. A 50/50 mixture of antifreeze and water is recommended and will protect against freezing down to -34 degrees F and boilover protection to 263 degrees F.
For maximum protection, up to a 70% mixture of antifreeze can be used for freezing protection to -84 degrees F.
CAUTION: Do not use more than 70% antifreeze, and never run straight water in the cooling system because it offers no corrosion, freezing or boilover protection.
Question:
I've heard about a new "environmentally safe" nonpoisonous antifreeze. What is it?
Answer:
It's propylene glycol (PG) antifreeze, sold under the "Sierra" brand name. Every other brand of antifreeze contains ethylene glycol (EG).
Antifreeze made with propylene glycol is being marketed as a "safer" alternative to ordinary antifreeze. Though it is by no means safe to drink, it is significantly less toxic than ordinary ethylene glycol antifreeze -- which may be a important difference to pet owners and parents of small children. PG also has an unpleasant taste which discourages further sampling by thirsty animals and toddlers. Safety is an important issue with coolants because of the frequency of spills, leaks and improper disposal.
According to one supplier of PG-based antifreeze, over 3,000 people in the U.S. were treated for ingesting antifreeze in 1991 (the latest year for which figures were available). Eight of them died. Had the antifreeze they ingested contained PG instead of EG, the consequences may not have been so dire.
Because of its significant safety advantages, PG coolants represent far less risk to wildlife in case of spills, leaks, or careless disposal. Because of this it can be claimed that PG coolants have an environmental benefit. However, both PG and EG are biodegradable and both may pick up lead or other heavy metals once they've been used in a cooling system. Both types of coolants, after being used, should be disposed of properly and in compliance with local regulations.
Though some auto makers were initially cautious about using PG when it was first introduced, GM has now said that propylene glycol may be used in GM vehicles without voiding the manufacturer's warranty coverage and will perform adequately under most vehicle operating conditions. Most vehicle manufacturers, however, don't currently use PG as a factory-fill antifreeze because of its higher cost (about $1 more per gallon at retail).
PERFORMANCE COMPARISON
When mixed with water (50/50 ratio), ordinary ethylene glycol antifreeze provides freezing protection to -34 degrees F. and boilover protection to 263 degrees F.. By comparison, propylene glycol provides freezing protection down to -27 degrees F. in a 50/50 mixture and boilover protection to 257 degrees F.. Though it might be argued that PG provides a few degrees less protection than EG, the difference can be easily offset by using a slightly higher concentration of PG in the coolant mix.
In terms of thermal efficiency (heat transfer), both types of antifreezes perform about the same (though EG has a marginal edge). Corrosion protection is about the same as long as the coolant is properly formulated with inhibitors.
ANTIFREEZE DISPOSAL & RECYCLING
Regardless of the type of antifreeze you use, it should be disposed of properly. In many areas, it is okay to flush used coolant down the toilet (sanitary sewer) as long as the amount does not exceed a few gallons. But it should not be poured down a floor drain or into a storm sewer.
Both types of antifreeze are biodegradable but take some time to break down. Dumping used antifreeze into a storm sewer, ditch, creek or on the ground can contaminate ground water and kill plants and fish. What's more, used antifreeze picks up lead from solder in copper/brass radiators. Lead is a toxic heavy metal that can also cause pollution problems of its own.
Some areas prohibit ANY dumping of used coolant (sanitary or storm sewers). They also may not accept used antifreeze in a sealed container for landfill collection because eventually the container will leak its contents into the ground causing possible ground water contamination.
So how do you get rid of the stuff? You can take it to a local collection center that accepts used antifreeze for disposal or recycling, you can pay to have it disposed of as a hazardous waste (yeah, right) -- or you can take your vehicle to a garage or service facility that has a coolant recycling machine. The latter is the best choice because it eliminates the disposal problem altogether.
Coolant recycling machines work their magic by a variety of means. Some use filtration while others use a distillation process to remove the harmful contaminants from the old antifreeze. Corrosion inhibiting chemicals are then added to restore the coolant's corrosion protection. The auto makers have all approved coolant recycling as an effective means of eliminating coolant disposal problems, and each publishes a list of machines that meet their specifications. Recycled coolant must meet minimum standards of purity before it can be reused.
Question:
What are the most common causes of engine overheating?
Answer:
THERMOSTAT STUCK SHUT
The thermostat, which is usually located in a housing where the upper radiator hose connects to the engine, controls the operating temperature of the engine. It does this by blocking the flow of coolant from the engine to the radiator until the engine reaches a certain temperature (usually 190 to 195 degrees F.). When this temperature is reached, the thermostat opens and allows coolant to circulate from the engine to the radiator.
If the thermostat fails to open, which can happen due to mechanical failure or if a steam pocket forms under the thermostat due to incomplete filling of the cooling system or coolant loss, no coolant will circulate between the engine and radiator, and the engine will quickly overheat.
You can check for this condition by carefully touching the upper radiator hose when the engine is first started and is warming up. If the upper radiator hose does not become hot to the touch within several minutes after starting the engine, it means the thermostat is probably defective and needs to be replaced.
CAUTION: The replacement thermostat should always have the same temperature rating as the original. Do not substitute a colder or hotter thermostat on any vehicle that has computerized engine controls as engine operating temperature affects the operation of the fuel, ignition and emissions control systems.
DEFECTIVE FAN CLUTCH
On rear wheel drive vehicles with belt-driven cooling fan, a "fan clutch" is often used to improve fuel economy. The clutch is a viscous-coupling filled with silicone oil. The clutch allows the fan to slip at high speed, which reduces the parasitic horsepower drag on the engine. If the clutch slips too much, however, the fan may not turn fast enough to keep the engine cool.
The silicone fluid inside the clutch breaks down over time and can leak out due to wear, too. If you see oily streaks radiating outward on the clutch (and/or the fan can be spun by hand with little or no resistance when the engine is off), it means the clutch is bad and needs to be replaced. Any play or wobble in the fan due to wear in the clutch also signals the need for a new clutch.
INOPERATIVE FAN MOTOR
On most front-wheel drive cars, the fan that cools the radiator is driven by an electric motor. A temperature switch or coolant sensor on the engine cycles the fan on and off as additional cooling is needed. If the temperature switch or coolant sensor (or the relay that routes power to the fan motor is bad), the fan won't come on when it is needed and the engine will overheat. Likewise, if the fan motor itself is bad, the fan won't work.
The system needs to be diagnosed to determine where the problem is so the correct component can be replaced.
EXTERNAL COOLANT LEAKS
Leaks in radiator or heater hoses, the water pump, radiator, heater core or engine freeze plugs can allow coolant to escape. No engine can tolerate the loss of coolant for very long, so it usually overheats as soon as a leak develops.
A visual inspection of the cooling system and engine will usually reveal where the coolant is going.
Leaks in hoses can only be fixed by replacing the hose. Leaks in the water pump also require replacing the pump. But leaks in a radiator, heater hose or freeze plug may sometimes respond to a sealer added to the cooling system.
WEAK OR LEAKY RADIATOR CAP
If no leaks are apparent, the radiator cap should be pressure tested to make sure it is holding the specified pressure. If the spring inside the cap is weak (or the cap is the wrong one for the application), the engine will lose coolant out the overflow tube every time it gets hot.
INTERNAL COOLANT LEAK
If there are no visible coolant leaks, but the engine is using coolant, there may be a crack in the cylinder head or block, or a leaky head gasket that is allowing coolant to escape into the combustion chamber or crankcase.
See related question #16 for more information.
EXHAUST RESTRICTION
In some instances a severe exhaust restriction can produce enough backpressure to cause an engine to overheat. The most likely cause of the blockage would be a plugged catalytic converter or a crushed or damaged pipe. Checking intake vacuum and/or exhaust backpressure can diagnose this kind of problem.
BAD WATER PUMP
In a high mileage engine, the impeller that pumps the coolant through the engine inside the water pump may be so badly corroded that the blades are loose or eaten away. If such is the case, the pump must be replaced.
Most pump failures, however, occur at the pump shaft bearing and seal. After tens of thousands of miles of operation, the bearing and seal wear out. Coolant starts to leak out past the shaft seal, which may cause the engine to overheat due to the loss of coolant. A sealer additive will not stop this kind of leak. Replacing the water pump is the only cure.
CAUTION: A leaky water pump should be replaced without delay, not only to reduce the risk of engine overheating but to prevent catastrophic pump failure. If the shaft breaks on a rear-wheel drive vehicle, the fan may go forward and chew into the radiator ruining the radiator.
Question:
Will a radiator stop leak additive really stop a coolant leak?
Answer:
Yes, but only if the leak is in a component that normally responds to such a product.
Leaks that can often be sealed with an additive include radiator and heater core pinholes (but not cracks), seepage leaks around engine freeze plugs, thermostat, manifold and head gaskets, and porosity leaks in aluminum heads or blocks.
Leaks that do not usually respond to additives include leaks in hoses, the water pump (around the shaft), or the radiator cap. Large cracks, cracks along outside corners or where hoses attach to the end tanks on the radiator are also very difficult to seal.
Even if a leak is sealed by an additive, no manufacturer will guarantee that such a seal will last. Repairing or replacing the leaky component, therefore, is the best cure -- and the only one that will guarantee lasting results.
Question:
My cooling system keeps losing coolant, but I don't see any leaks. Where is it going?
Answer:
You probably have an "internal" coolant leak inside your engine. The coolant is escaping into the combustion chamber or crankcase through cracks in the cylinder head or block, or through a leaky head gasket.
In rare instances, coolant may also leak into the automatic transmission fluid cooler if one is located inside the radiator. But usually when automatic transmission fluid leaks into the coolant it means the line is leaking.
Pressure testing the cooling system is necessary to diagnose an internal leak. A "cylinder leak-down test" can tell a mechanic if the coolant leak is in the combustion chamber. But to pinpoint an internal leak, it is usually necessary to remove the head(s) from the engine. The head may then be pressure tested and/or checked for cracks using special equipment.
Minor internal leaks can sometimes be temporarily sealed by adding a sealer to the cooling system. But large leaks or ones that do not respond to a sealer will have to be fixed.
If the problem is a cracked head or block, repairs may or may not be possible depending on the nature of the crack. Cracks in aluminum can often be repaired by welding while those in cast iron can be fixed by pinning the damaged area. But some cracks may be so bad that they are beyond repair or in a location that makes repair impossible. In such cases, the head or block must be replaced.
If a leaky head gasket is the culprit, replacing the gasket may only temporarily cure the problem if the head or block is warped. The mating surfaces on both the head and block should be checked for flatness and resurfaced if necessary to restore flatness for a proper seal.
Answer: For "ordinary" antifreeze, the vehicle manufacturers generally recommend coolant changes every two to three years or 30,000 miles. Others say it's not a bad idea to change the coolant every year for maximum corrosion protection -- especially in vehicles that have aluminum heads, blocks or radiators. But such recommendations may soon be obsolete. Several antifreeze suppliers have just recently introduced "long life" antifreeze formulations that claim to provide protection for four years or 50,000 miles.
General Motors just introduced a new five year, 100,000 mile antifreeze in its 1996 cars and light trucks. The new coolant is called "Dex-Cool" and is dyed orange to distinguish it from ordinary antifreeze (which is green).
CAUTION: These new long life coolants provide extended life only when used in a clean system mixed with water. If mixed with ordinary antifreeze and/or old coolant in a system, the corrosion protection is reduced to that of normal antifreeze (2 to 3 years and 30,000 miles).
CORROSION INHIBITORS
The life of the antifreeze depends on it's ability to inhibit corrosion. Silicates, phosphates and/or borates are used as corrosion inhibitors to keep the solution alkaline. As long as the antifreeze remains so, corrosion is held in check and there's no need to change the coolant. But as the corrosion inhibiting chemicals are used up over time, electrolytic corrosion starts to eat away at the metal inside the engine and radiator. Aluminum is especially vulnerable to corrosion and can turn to Swiss cheese rather quickly when conditions are right. Solder bloom can also form in copper\brass radiators causing leaks and restrictions. So changing the coolant periodically as preventative maintenance is a good way to prevent costly repairs.
The basic idea is to change the coolant before the corrosion inhibitors reach dangerously low levels. Following the OEM change recommendations is usually good enough to keep corrosion in check, but it may not always be the case. That's why more frequent changes may be recommended to minimize the risk of corrosion in bimetal engines and aluminum radiators.
CHECKING THE ANTIFREEZE
One way to find out if it's time to change the antifreeze is to test it. Several suppliers make special antifreeze test strips that react to the pH (alkalinity) of the coolant and change color. If the test strip indicates a marginal or bad condition, the coolant should be changed.
CHANGING THE COOLANT
Reverse flushing is the best way to change the coolant because draining alone can leave as much as 30 to 50% of the old coolant in the engine block. Reverse flushing also helps dislodge deposits and scale which can interfere with good heat transfer.
The concentration of antifreeze in the coolant also needs to be checked prior to the onset of cold weather. A 50/50 mixture of antifreeze and water is recommended and will protect against freezing down to -34 degrees F and boilover protection to 263 degrees F.
For maximum protection, up to a 70% mixture of antifreeze can be used for freezing protection to -84 degrees F.
CAUTION: Do not use more than 70% antifreeze, and never run straight water in the cooling system because it offers no corrosion, freezing or boilover protection.
Question:
I've heard about a new "environmentally safe" nonpoisonous antifreeze. What is it?
Answer:
It's propylene glycol (PG) antifreeze, sold under the "Sierra" brand name. Every other brand of antifreeze contains ethylene glycol (EG).
Antifreeze made with propylene glycol is being marketed as a "safer" alternative to ordinary antifreeze. Though it is by no means safe to drink, it is significantly less toxic than ordinary ethylene glycol antifreeze -- which may be a important difference to pet owners and parents of small children. PG also has an unpleasant taste which discourages further sampling by thirsty animals and toddlers. Safety is an important issue with coolants because of the frequency of spills, leaks and improper disposal.
According to one supplier of PG-based antifreeze, over 3,000 people in the U.S. were treated for ingesting antifreeze in 1991 (the latest year for which figures were available). Eight of them died. Had the antifreeze they ingested contained PG instead of EG, the consequences may not have been so dire.
Because of its significant safety advantages, PG coolants represent far less risk to wildlife in case of spills, leaks, or careless disposal. Because of this it can be claimed that PG coolants have an environmental benefit. However, both PG and EG are biodegradable and both may pick up lead or other heavy metals once they've been used in a cooling system. Both types of coolants, after being used, should be disposed of properly and in compliance with local regulations.
Though some auto makers were initially cautious about using PG when it was first introduced, GM has now said that propylene glycol may be used in GM vehicles without voiding the manufacturer's warranty coverage and will perform adequately under most vehicle operating conditions. Most vehicle manufacturers, however, don't currently use PG as a factory-fill antifreeze because of its higher cost (about $1 more per gallon at retail).
PERFORMANCE COMPARISON
When mixed with water (50/50 ratio), ordinary ethylene glycol antifreeze provides freezing protection to -34 degrees F. and boilover protection to 263 degrees F.. By comparison, propylene glycol provides freezing protection down to -27 degrees F. in a 50/50 mixture and boilover protection to 257 degrees F.. Though it might be argued that PG provides a few degrees less protection than EG, the difference can be easily offset by using a slightly higher concentration of PG in the coolant mix.
In terms of thermal efficiency (heat transfer), both types of antifreezes perform about the same (though EG has a marginal edge). Corrosion protection is about the same as long as the coolant is properly formulated with inhibitors.
ANTIFREEZE DISPOSAL & RECYCLING
Regardless of the type of antifreeze you use, it should be disposed of properly. In many areas, it is okay to flush used coolant down the toilet (sanitary sewer) as long as the amount does not exceed a few gallons. But it should not be poured down a floor drain or into a storm sewer.
Both types of antifreeze are biodegradable but take some time to break down. Dumping used antifreeze into a storm sewer, ditch, creek or on the ground can contaminate ground water and kill plants and fish. What's more, used antifreeze picks up lead from solder in copper/brass radiators. Lead is a toxic heavy metal that can also cause pollution problems of its own.
Some areas prohibit ANY dumping of used coolant (sanitary or storm sewers). They also may not accept used antifreeze in a sealed container for landfill collection because eventually the container will leak its contents into the ground causing possible ground water contamination.
So how do you get rid of the stuff? You can take it to a local collection center that accepts used antifreeze for disposal or recycling, you can pay to have it disposed of as a hazardous waste (yeah, right) -- or you can take your vehicle to a garage or service facility that has a coolant recycling machine. The latter is the best choice because it eliminates the disposal problem altogether.
Coolant recycling machines work their magic by a variety of means. Some use filtration while others use a distillation process to remove the harmful contaminants from the old antifreeze. Corrosion inhibiting chemicals are then added to restore the coolant's corrosion protection. The auto makers have all approved coolant recycling as an effective means of eliminating coolant disposal problems, and each publishes a list of machines that meet their specifications. Recycled coolant must meet minimum standards of purity before it can be reused.
Question:
What are the most common causes of engine overheating?
Answer:
THERMOSTAT STUCK SHUT
The thermostat, which is usually located in a housing where the upper radiator hose connects to the engine, controls the operating temperature of the engine. It does this by blocking the flow of coolant from the engine to the radiator until the engine reaches a certain temperature (usually 190 to 195 degrees F.). When this temperature is reached, the thermostat opens and allows coolant to circulate from the engine to the radiator.
If the thermostat fails to open, which can happen due to mechanical failure or if a steam pocket forms under the thermostat due to incomplete filling of the cooling system or coolant loss, no coolant will circulate between the engine and radiator, and the engine will quickly overheat.
You can check for this condition by carefully touching the upper radiator hose when the engine is first started and is warming up. If the upper radiator hose does not become hot to the touch within several minutes after starting the engine, it means the thermostat is probably defective and needs to be replaced.
CAUTION: The replacement thermostat should always have the same temperature rating as the original. Do not substitute a colder or hotter thermostat on any vehicle that has computerized engine controls as engine operating temperature affects the operation of the fuel, ignition and emissions control systems.
DEFECTIVE FAN CLUTCH
On rear wheel drive vehicles with belt-driven cooling fan, a "fan clutch" is often used to improve fuel economy. The clutch is a viscous-coupling filled with silicone oil. The clutch allows the fan to slip at high speed, which reduces the parasitic horsepower drag on the engine. If the clutch slips too much, however, the fan may not turn fast enough to keep the engine cool.
The silicone fluid inside the clutch breaks down over time and can leak out due to wear, too. If you see oily streaks radiating outward on the clutch (and/or the fan can be spun by hand with little or no resistance when the engine is off), it means the clutch is bad and needs to be replaced. Any play or wobble in the fan due to wear in the clutch also signals the need for a new clutch.
INOPERATIVE FAN MOTOR
On most front-wheel drive cars, the fan that cools the radiator is driven by an electric motor. A temperature switch or coolant sensor on the engine cycles the fan on and off as additional cooling is needed. If the temperature switch or coolant sensor (or the relay that routes power to the fan motor is bad), the fan won't come on when it is needed and the engine will overheat. Likewise, if the fan motor itself is bad, the fan won't work.
The system needs to be diagnosed to determine where the problem is so the correct component can be replaced.
EXTERNAL COOLANT LEAKS
Leaks in radiator or heater hoses, the water pump, radiator, heater core or engine freeze plugs can allow coolant to escape. No engine can tolerate the loss of coolant for very long, so it usually overheats as soon as a leak develops.
A visual inspection of the cooling system and engine will usually reveal where the coolant is going.
Leaks in hoses can only be fixed by replacing the hose. Leaks in the water pump also require replacing the pump. But leaks in a radiator, heater hose or freeze plug may sometimes respond to a sealer added to the cooling system.
WEAK OR LEAKY RADIATOR CAP
If no leaks are apparent, the radiator cap should be pressure tested to make sure it is holding the specified pressure. If the spring inside the cap is weak (or the cap is the wrong one for the application), the engine will lose coolant out the overflow tube every time it gets hot.
INTERNAL COOLANT LEAK
If there are no visible coolant leaks, but the engine is using coolant, there may be a crack in the cylinder head or block, or a leaky head gasket that is allowing coolant to escape into the combustion chamber or crankcase.
See related question #16 for more information.
EXHAUST RESTRICTION
In some instances a severe exhaust restriction can produce enough backpressure to cause an engine to overheat. The most likely cause of the blockage would be a plugged catalytic converter or a crushed or damaged pipe. Checking intake vacuum and/or exhaust backpressure can diagnose this kind of problem.
BAD WATER PUMP
In a high mileage engine, the impeller that pumps the coolant through the engine inside the water pump may be so badly corroded that the blades are loose or eaten away. If such is the case, the pump must be replaced.
Most pump failures, however, occur at the pump shaft bearing and seal. After tens of thousands of miles of operation, the bearing and seal wear out. Coolant starts to leak out past the shaft seal, which may cause the engine to overheat due to the loss of coolant. A sealer additive will not stop this kind of leak. Replacing the water pump is the only cure.
CAUTION: A leaky water pump should be replaced without delay, not only to reduce the risk of engine overheating but to prevent catastrophic pump failure. If the shaft breaks on a rear-wheel drive vehicle, the fan may go forward and chew into the radiator ruining the radiator.
Question:
Will a radiator stop leak additive really stop a coolant leak?
Answer:
Yes, but only if the leak is in a component that normally responds to such a product.
Leaks that can often be sealed with an additive include radiator and heater core pinholes (but not cracks), seepage leaks around engine freeze plugs, thermostat, manifold and head gaskets, and porosity leaks in aluminum heads or blocks.
Leaks that do not usually respond to additives include leaks in hoses, the water pump (around the shaft), or the radiator cap. Large cracks, cracks along outside corners or where hoses attach to the end tanks on the radiator are also very difficult to seal.
Even if a leak is sealed by an additive, no manufacturer will guarantee that such a seal will last. Repairing or replacing the leaky component, therefore, is the best cure -- and the only one that will guarantee lasting results.
Question:
My cooling system keeps losing coolant, but I don't see any leaks. Where is it going?
Answer:
You probably have an "internal" coolant leak inside your engine. The coolant is escaping into the combustion chamber or crankcase through cracks in the cylinder head or block, or through a leaky head gasket.
In rare instances, coolant may also leak into the automatic transmission fluid cooler if one is located inside the radiator. But usually when automatic transmission fluid leaks into the coolant it means the line is leaking.
Pressure testing the cooling system is necessary to diagnose an internal leak. A "cylinder leak-down test" can tell a mechanic if the coolant leak is in the combustion chamber. But to pinpoint an internal leak, it is usually necessary to remove the head(s) from the engine. The head may then be pressure tested and/or checked for cracks using special equipment.
Minor internal leaks can sometimes be temporarily sealed by adding a sealer to the cooling system. But large leaks or ones that do not respond to a sealer will have to be fixed.
If the problem is a cracked head or block, repairs may or may not be possible depending on the nature of the crack. Cracks in aluminum can often be repaired by welding while those in cast iron can be fixed by pinning the damaged area. But some cracks may be so bad that they are beyond repair or in a location that makes repair impossible. In such cases, the head or block must be replaced.
If a leaky head gasket is the culprit, replacing the gasket may only temporarily cure the problem if the head or block is warped. The mating surfaces on both the head and block should be checked for flatness and resurfaced if necessary to restore flatness for a proper seal.
Under hood Maintenance: Brake Fluid
Question: My brake pedal slowly sinks to the floor when I hold my foot on it. What's wrong?
Answer: You either have a fluid leak in your brake system or your master cylinder is defective. Either way, your brakes need immediate attention.
If the brake warning light is on, you most likely have a fluid leak. Your vehicle may not be safe to drive in this condition! You should have the brakes inspected as soon as possible to determine where the fluid is leaking (usually a hose, brake line, brake caliper or wheel cylinder) so the necessary repairs can be made.
If the brake warning light is not on, it does not necessarily mean you do not have a leak. The warning light only comes on when there's been enough fluid loss to create a pressure differential between the two sides of the hydraulic system that actually apply the brakes.
The brake system is divided into two hydraulic circuits. On most rear-wheel drive vehicles, it is divided so one circuit applies the front brakes and the other applies the rear brakes. On front-wheel drive cars and minivans, the system is usually split diagonally. One circuit works the right front and left rear brake, and the other works the left front and right rear brake. This is done for safety purposes so if one circuit loses all its brake fluid and fails, the vehicle will still have one remaining circuit to apply two wheel brakes.
A quick way to check for leaks in either circuit is to simply check the fluid level in the master cylinder reservoir. The reservoir is divided into two chambers (one for each brake circuit). If one chamber is unusually low or empty, there's a leak somewhere in that circuit. The brakes should then be inspected to check for fluid leaks. Wet spots around hose or line connections, or fluid leaking from a disc brake caliper or drum wheel cylinder would indicate a serious problem that needs immediate attention.
If the brake warning light is not on and there are no apparent leaks, then the master cylinder may be worn or leaking internally allowing the pedal to slowly sink when pressure is applied to it. This type of condition will be most noticeable when holding constant pressure against the brake pedal at a stop light. If the pedal sinks or requires pumping to keep the car from creeping ahead, the master cylinder needs to be replaced.
On some vehicles with rear-wheel antilock brake systems (ABS), it's also possible that a leak in the ABS unit may cause a similar sinking pedal condition.
Question:
My brake pedal is low when I step on it, but it comes up when I pump the brakes. Do I need new brakes?
Answer:
A low brake pedal that has to be pumped repeatedly to bring a vehicle to a stop may be due to a low fluid level, drum brakes that need adjustment or air in the lines. It usually has nothing to do with the condition of the brakes and certainly isn't grounds for a brake job.
If the pedal feels "soft" or "spongy" instead of firm, there's probably air in the system. This will require "bleeding the brakes" to remove air from the lines, calipers and wheel cylinders.
The first thing that should be checked is the fluid level in the master cylinder reservoir. If the level is low, there's a leak somewhere in the hydraulic system that must be found and repaired. Adding fluid will only cure the symptom, not the cause, and sooner or later the level will be low again creating a dangerous situation. So check for leaks around the master cylinder, wheel cylinders, brake calipers, rubber brake hoses and steel brake lines.
If the fluid level is okay, the adjustment of the rear brakes should be checked next (assuming the vehicle has drum brakes in the rear -- if it has drums all the way around, check the front drums first, then the rear). The shoes should be close enough to the drums to produce just a hint of drag when the wheels are rotated by hand. An excess of slack probably means the self-adjusters are either frozen or fully extended.
If adjusting the drum brakes fails to eliminate the low pedal, the wheel and drum will have to be removed so the adjusters can be freed up or replaced, and/or so the worn brake shoes can be replaced.
If the vehicle has rear disc brakes, the adjusting mechanism in the rear caliper pistons that maintain the correct pad-to-rotor clearance may be corroded, frozen or worn out. In most cases, the piston assemblies cannot be rebuilt and must be replaced.
If the fluid reservoir is full and the brakes are properly adjusted, but the pedal is low (or feels spongy), there is probably air in the brake lines. Air is compressible, so every time you step on the pedal, the bubbles collapse instead of transferring pressure to the brakes. The cure here is to bleed the brake lines following the factory recommended sequence.
Brakes are usually bled in a specified sequence (always refer to a shop manual for the exact procedure for your vehicle). Usually the rear brakes are bled first, then the ones up front on most rear-wheel drive cars and trucks. But on front-wheel drive cars and minivans, the hydraulic system is split diagonally so the brakes are bled in opposite pairs (right rear and left front, then left rear and right front). Following the proper sequence is important so air doesn't remain trapped in the lines.
On late model GM and Ford cars with quick take-up master cylinders, the quick take-up valve takes about 15 seconds to reseat after the brake pedal has been depressed. If the pedal is pumped too quickly while manually bleeding the system, you may never get the pedal to firm up. Most professionals use pressure bleeding equipment to bleed the brakes because it is faster and easier.
Answer: You either have a fluid leak in your brake system or your master cylinder is defective. Either way, your brakes need immediate attention.
If the brake warning light is on, you most likely have a fluid leak. Your vehicle may not be safe to drive in this condition! You should have the brakes inspected as soon as possible to determine where the fluid is leaking (usually a hose, brake line, brake caliper or wheel cylinder) so the necessary repairs can be made.
If the brake warning light is not on, it does not necessarily mean you do not have a leak. The warning light only comes on when there's been enough fluid loss to create a pressure differential between the two sides of the hydraulic system that actually apply the brakes.
The brake system is divided into two hydraulic circuits. On most rear-wheel drive vehicles, it is divided so one circuit applies the front brakes and the other applies the rear brakes. On front-wheel drive cars and minivans, the system is usually split diagonally. One circuit works the right front and left rear brake, and the other works the left front and right rear brake. This is done for safety purposes so if one circuit loses all its brake fluid and fails, the vehicle will still have one remaining circuit to apply two wheel brakes.
A quick way to check for leaks in either circuit is to simply check the fluid level in the master cylinder reservoir. The reservoir is divided into two chambers (one for each brake circuit). If one chamber is unusually low or empty, there's a leak somewhere in that circuit. The brakes should then be inspected to check for fluid leaks. Wet spots around hose or line connections, or fluid leaking from a disc brake caliper or drum wheel cylinder would indicate a serious problem that needs immediate attention.
If the brake warning light is not on and there are no apparent leaks, then the master cylinder may be worn or leaking internally allowing the pedal to slowly sink when pressure is applied to it. This type of condition will be most noticeable when holding constant pressure against the brake pedal at a stop light. If the pedal sinks or requires pumping to keep the car from creeping ahead, the master cylinder needs to be replaced.
On some vehicles with rear-wheel antilock brake systems (ABS), it's also possible that a leak in the ABS unit may cause a similar sinking pedal condition.
Question:
My brake pedal is low when I step on it, but it comes up when I pump the brakes. Do I need new brakes?
Answer:
A low brake pedal that has to be pumped repeatedly to bring a vehicle to a stop may be due to a low fluid level, drum brakes that need adjustment or air in the lines. It usually has nothing to do with the condition of the brakes and certainly isn't grounds for a brake job.
If the pedal feels "soft" or "spongy" instead of firm, there's probably air in the system. This will require "bleeding the brakes" to remove air from the lines, calipers and wheel cylinders.
The first thing that should be checked is the fluid level in the master cylinder reservoir. If the level is low, there's a leak somewhere in the hydraulic system that must be found and repaired. Adding fluid will only cure the symptom, not the cause, and sooner or later the level will be low again creating a dangerous situation. So check for leaks around the master cylinder, wheel cylinders, brake calipers, rubber brake hoses and steel brake lines.
If the fluid level is okay, the adjustment of the rear brakes should be checked next (assuming the vehicle has drum brakes in the rear -- if it has drums all the way around, check the front drums first, then the rear). The shoes should be close enough to the drums to produce just a hint of drag when the wheels are rotated by hand. An excess of slack probably means the self-adjusters are either frozen or fully extended.
If adjusting the drum brakes fails to eliminate the low pedal, the wheel and drum will have to be removed so the adjusters can be freed up or replaced, and/or so the worn brake shoes can be replaced.
If the vehicle has rear disc brakes, the adjusting mechanism in the rear caliper pistons that maintain the correct pad-to-rotor clearance may be corroded, frozen or worn out. In most cases, the piston assemblies cannot be rebuilt and must be replaced.
If the fluid reservoir is full and the brakes are properly adjusted, but the pedal is low (or feels spongy), there is probably air in the brake lines. Air is compressible, so every time you step on the pedal, the bubbles collapse instead of transferring pressure to the brakes. The cure here is to bleed the brake lines following the factory recommended sequence.
Brakes are usually bled in a specified sequence (always refer to a shop manual for the exact procedure for your vehicle). Usually the rear brakes are bled first, then the ones up front on most rear-wheel drive cars and trucks. But on front-wheel drive cars and minivans, the hydraulic system is split diagonally so the brakes are bled in opposite pairs (right rear and left front, then left rear and right front). Following the proper sequence is important so air doesn't remain trapped in the lines.
On late model GM and Ford cars with quick take-up master cylinders, the quick take-up valve takes about 15 seconds to reseat after the brake pedal has been depressed. If the pedal is pumped too quickly while manually bleeding the system, you may never get the pedal to firm up. Most professionals use pressure bleeding equipment to bleed the brakes because it is faster and easier.
Under hood Maintenance: Battery
Q & A: Battery
1. How can I tell if my battery is low and needs to recharged?
Answer:
The first and most likely indication of a low battery would be a hard starting problem caused by slow cranking. If the battery seems weak or fails to crank your engine normally, it may be low. To find out, you need to check the battery's "state of charge."
A battery is nothing more than a chemical storage device for holding electrons until they're needed to crank the engine or run the lights or other electrical accessories on your vehicle. Checking the battery's state of charge will tell you how much juice the battery has available for such purposes.
If your battery is low, it needs to be recharged, not only to restore full power, but also to prevent possible damage to the battery. Ordinary automotive lead-acid storage batteries must be kept at or near full charge to keep the cell plates from becoming "sulfated" (a condition that occurs if the battery is run down and left in a discharged condition for more than a few days). As sulfate builds up, it reduces the battery's ability to hold a charge and supply voltage. Eventually the battery becomes useless and must be replaced.
CHECKING THE STATE OF CHARGE
The charge level depends on the concentration of acid inside the battery. The stronger the concentration of acid in the water, the higher the specific gravity of the solution, and the higher the state of charge.
On batteries with removable caps, state of charge can be checked with a "hydrometer." Some hydrometers have a calibrated float to measure the specific gravity of the acid solution while others simply have a number of colored balls. On the kind with a calibrated float, a hydrometer reading of 1.265 (corrected for temperature) indicates a fully charged battery, 1.230 indicates a 75% charge, 1.200 indicates a 50% charge, 1.170 indicates a 25% charge, and 1.140 or less indicates a discharged battery. On the kind that use floating balls, the number of balls that float tells you the approximate level of charge. All balls floating would indicate a fully charged battery, no balls floating would indicate a dead or fully discharged battery.
Some sealed-top batteries have a built-in hydrometer to indicate charge. The charge indicator only reads one cell, but usually shows the average charge for all battery cells. A green dot means the battery is 75% or more charged and is okay for use or further testing. No dot (a dark indicator) means the battery is low and should be recharged before it is returned to service or tested further. A clear or yellow indicator means the level of electrolyte inside has dropped too low, and the battery should be replaced.
On sealed-top batteries that do not have a built-in charge indicator, the state of charge can be determined by checking the battery's base or open circuit voltage with a digital voltmeter or multimeter. This is done by touching the meter leads to the positive and negative battery terminals while the ignition key is off.
A reading of 12.66 volts indicates a fully charged battery; 12.45 volts is 75% charged, 12.24 volts is 50% charged, and 12.06 volts is 25% charged.
RECHARGING THE BATTERY
CAUTION: Do not attempt to recharge a battery with low (or frozen) electrolyte! Doing so risks blowing up the battery if the hydrogen gas inside is ignited by a spark.
Your charging system should be capable of recharging the battery if it is not fully discharged. Thirty minutes or so of normal driving should be enough.
If your battery is completely dead or extremely low, it should be recharged with a fast or slow charger. This will reduce the risk of overtaxing and damaging your vehicle's charging system. One or both battery cables should be disconnected from the battery prior to charging it with a charger. This will eliminate any risk of damage to your vehicle's electrical system or its onboard electronics.
Question:
2. My battery keeps running down. Do I need a new battery?
Answer:
It might, but then again it might not. The only way to know for sure is to (1) test the condition of the battery to see if it is capable of holding a charge, (2) check the output of the charging system to see if it is functioning properly, and (3) if the battery and charging system are okay, check for a possible current drain on the battery when the key is off. In other words, if the battery is okay and the charging system is doing its job, then something is draining voltage from the battery and running it down when the key is off.
One way to check the battery is to recharge it, then let it sit for a day with both battery cables disconnected. If the battery holds the charge and doesn't run down, it's probably okay, and the problem is in your charging system or wiring.
To see if the charging system is working properly, start the car and turn on the headlights. If the headlights are dim, it indicates the lights are running off the battery and that little or no juice is being produced by the alternator. If the lights get brighter as you rev the engine, it means the alternator is producing some current, but may not be producing enough at idle to keep the battery properly charged. If the lights have normal brightness and don't change intensity as the engine is revved, your charging system is functioning normally.
You can also check the charging system by connecting the leads of a voltmeter to the battery. When the engine starts, the charging voltage should jump to about 14.5 or higher. If the reading doesn't change or rises less than a volt, you have a charging problem that will require further diagnosis.
If the battery and charging system seem to be working normally, the only thing that's left is the electrical system. If the battery runs down overnight or when the vehicle sits for several days, it means something is remaining on and drawing current when the ignition is turned off. It may be a trunk light or cigarette lighter that remains on all the time, a fuel pump relay or other relay with frozen contacts that's drawing current, a rear window defroster that doesn't shut off, or a short in the radio or other electrical accessory.
All vehicles draw a little current from the battery when the key is off to run the clock, keep the memory alive in a digital radio (so it doesn't forget the station settings) and the engine computer. Alarm systems need current to keep their circuits armed as do cellular phones.
Current drain on the battery can be checked with an ammeter. Make sure the ignition is off, then disconnect one of the battery cables. Connect one ammeter lead to the battery and the other to the cable. The normal current drain on most vehicles should be about 25 milliamps or less. If the key-off drain exceeds 100 milliamps, there's an electrical problem that requires further diagnosis.
Finding the hidden current drain can be time consuming. The easiest way to isolate the problem is to pull one fuse at a time from the fuse panel until the ammeter reading drops. This will tell you which circuit is draining the battery. Then you have to check the wiring and each of the components in that circuit to pinpoint the problem.
Question:
3. How can I tell if my battery is good or bad?
Answer:
The condition of the cell plates inside the battery determines whether or not a battery is still serviceable. Current is produced when sulfuric acid in the battery reacts with lead in the cell plates. As the battery discharges, sulfate accumulates on the plates and reduces the battery's ability to make current. The sulfate is returned to solution when the alternator recharges the battery by forcing current to flow in the opposite direction.
Over time, some of the sulfate becomes permanently attached to the plates. The sulfate forms a barrier that diminishes the battery's ability to produce and store electricity. This process can be accelerated if the battery is run down frequently or is allowed to remain in a discharged state for more than a few days. If the plates have become sulfated, therefore, the battery won't accept a charge and will have to be replaced.
Average battery life is only about four to five years under the best of circumstances -- and sometimes as short as two to three years in extremely hot climates such as Arizona and New Mexico. But the battery may become "sulfated" prematurely if it is chronically undercharged (charging problems or frequent short-trip driving), or if the water level inside the battery drops below the top of the cell plates as a result of hot weather or overcharging and allows the cell plates to dry out.
BATTERY TESTING
This is something you can't really do yourself, so you need to take your vehicle to a service facility that has the proper test equipment. The battery's condition can be determined one of two ways: with a carbon pile "load test" (that applies a calibrated load to the battery) or electronically with a special tester that measures the battery's internal resistance.
Equipment that uses a carbon pile for load testing requires the battery to be at least 75% charged. If the battery is less than 75% charged, a good battery may fail the test. So the state of charge must be checked first, and the battery recharged if it is low prior to testing. NOTE: The battery does NOT have to be fully charged prior to testing if an electronic tester that measures internal resistance is being used.
If load testing with a carbon pile, apply a load that is equal to half the battery's cold cranking amps (CCA) rating. A good battery should be able to supply half its CCA rating for fifteen seconds without dropping below 9.5 volts.
Question:
4. Does a replacement battery need to be the same size as my old one?
Answer:
No. If your old battery has reached the end of the road and needs to be replaced, or if you think you need a battery with a bigger amp capacity for easier cold weather starting or to handle added electrical accessories (such as a killer stereo system, driving lights, etc.), then there's no reason why you have to install a battery that's the same size as your old one.
The word "size" may be a bit confusing here because what we're really talking about is the battery's amp or power rating, not the physical dimensions of its case.
A battery with a bigger case is not necessarily a more powerful battery. Battery manufacturers can cram a lot of amps into a relatively small box by varying the design of the cell plates and grids. So two batteries with identical exterior dimensions may have significantly different power ratings.
Batteries come in many different sizes and configurations (which are referred to as "group" sizes) because the vehicle manufacturers can't get together and standardize anything. So when you're choosing a battery, you have to consider three things: (1) the group size (height, width, length and post configuration), (2) whether your battery has top or side posts, and (3) how many amps will be needed for reliable cold starting and vehicle operation.
GROUP SIZES
Because there are 57 different group sizes, many aftermarket replacement battery suppliers consolidate group sizes to simplify inventory requirements. So some replacement batteries may not fit exactly the same as the original. The battery may be slightly shorter, taller, narrower or wider than the original. But as long as it fits the battery tray and there are no interference problems (too tall a battery may cause the cables to make contact with the hood causing a dangerous and damaging electrical short!), it should work fine.
Some replacement batteries come with both side and top posts to further consolidate applications. Some also have folding handles to make handling and installation easier.
BATTERY RATINGS
Though many replacement batteries are marketed by the number of "months" of warranty coverage provided (36, 48, 60, etc.), what's more important in terms of performance is the battery's power rating which is usually specified in "Cold Cranking Amps" (CCA) rating. The CCA rating tells you how many amps the battery can deliver at 0 degree F. for 30 seconds and still maintain a minimum voltage of 1.2v. per cell.
In the past, the rule of thumb was to always buy a battery with a rating of at least one CCA per cubic inch of engine displacement. But twice that is probably a better recommendation for reliable cold weather starting.
At the very least, you should buy a replacement battery with the same or better CCA rating as your old battery or one that meets the vehicle manufacturer's requirements. For most small four-cylinder engines, this would be a 450 CCA or larger battery, for a six cylinder application, a 550 CCA or larger battery, and for a V8 a 650 CCA or larger battery. Bigger is usually better. Extra battery capacity is recommended if your vehicle has a lot of electrical accessories such as air conditioning, power windows, seats, electric rear defogger, etc.
BATTERY INSTALLATION
Most batteries are "dry charged" at the factory, which means they're activated as soon as acid is poured into the cells. Even so, the battery may require some charging to bring it all the way up to full charge.
Most experts recommend charging the battery before it is installed regardless of whether it is dry charged or not. This will ensure the battery is at full charge and lessen the strain on your charging system.
When the battery is installed, it must be locked down and held securely by a clamp, strap or bracket. This will not only keep the battery from sliding around on its tray (which might allow the positive cable to touch against something and short out the battery or start a fire!), but will also help to minimize vibration that can damage the battery.
The battery cables should also be inspected to make sure they're in good condition, too. If the cables are badly corroded, don't fit the battery posts or terminals tightly, or have been "fixed" by installing temporary clamps on the ends, the cables should be replaced. At the very least, you should clean the cable clamps and battery posts with a post cleaner, sandpaper or a wire brush to ensure good electrical contact. A light coating of grease, petroleum jelly and/or installing chemically treated felt washers under the cable clamps will help prevent corrosion.
Question:
5. Is there any danger to me or my vehicle if I give someone a "jump start?"
Answer:
Yes. The danger to you is a battery explosion. Batteries contain hydrogen gas, which can ignite and explode if a spark occurs anywhere near the battery. Batteries also contain acid which may be splashed on you if the battery explodes.
The danger to your vehicle is if someone reverses the jumper connections or touches the jumper cables together. The voltage surge that results may damage your charging system and/or other electronic components in your vehicle.
To minimize these risks, use the following procedure when jump starting :
The reason for not doing this is because the final jumper connection usually produces a spark. Making the final connection away from the battery will minimize any danger of an explosion by keeping the spark well away from the battery.
If the vehicle does not crank or cranks slowly, recheck the jumper connections. If it still doesn't crank, the problem may be something other then the battery (such as a bad starter, solenoid, battery cable connection or internal engine problem).
If the vehicle cranks normally, but refuses to start, it may have an ignition, fuel or mechanical problem.
Do not crank the starter more than thirty seconds at a stretch. Allow the starter to cool for about two minutes before cranking the engine again. Continuous grinding of the starter can cause it to overheat and fail. Continuous cranking can also sap the juice out of your good battery and/or overload and possibly damage your charging system, too!
1. How can I tell if my battery is low and needs to recharged?
Answer:
The first and most likely indication of a low battery would be a hard starting problem caused by slow cranking. If the battery seems weak or fails to crank your engine normally, it may be low. To find out, you need to check the battery's "state of charge."
A battery is nothing more than a chemical storage device for holding electrons until they're needed to crank the engine or run the lights or other electrical accessories on your vehicle. Checking the battery's state of charge will tell you how much juice the battery has available for such purposes.
If your battery is low, it needs to be recharged, not only to restore full power, but also to prevent possible damage to the battery. Ordinary automotive lead-acid storage batteries must be kept at or near full charge to keep the cell plates from becoming "sulfated" (a condition that occurs if the battery is run down and left in a discharged condition for more than a few days). As sulfate builds up, it reduces the battery's ability to hold a charge and supply voltage. Eventually the battery becomes useless and must be replaced.
CHECKING THE STATE OF CHARGE
The charge level depends on the concentration of acid inside the battery. The stronger the concentration of acid in the water, the higher the specific gravity of the solution, and the higher the state of charge.
On batteries with removable caps, state of charge can be checked with a "hydrometer." Some hydrometers have a calibrated float to measure the specific gravity of the acid solution while others simply have a number of colored balls. On the kind with a calibrated float, a hydrometer reading of 1.265 (corrected for temperature) indicates a fully charged battery, 1.230 indicates a 75% charge, 1.200 indicates a 50% charge, 1.170 indicates a 25% charge, and 1.140 or less indicates a discharged battery. On the kind that use floating balls, the number of balls that float tells you the approximate level of charge. All balls floating would indicate a fully charged battery, no balls floating would indicate a dead or fully discharged battery.
Some sealed-top batteries have a built-in hydrometer to indicate charge. The charge indicator only reads one cell, but usually shows the average charge for all battery cells. A green dot means the battery is 75% or more charged and is okay for use or further testing. No dot (a dark indicator) means the battery is low and should be recharged before it is returned to service or tested further. A clear or yellow indicator means the level of electrolyte inside has dropped too low, and the battery should be replaced.
On sealed-top batteries that do not have a built-in charge indicator, the state of charge can be determined by checking the battery's base or open circuit voltage with a digital voltmeter or multimeter. This is done by touching the meter leads to the positive and negative battery terminals while the ignition key is off.
A reading of 12.66 volts indicates a fully charged battery; 12.45 volts is 75% charged, 12.24 volts is 50% charged, and 12.06 volts is 25% charged.
RECHARGING THE BATTERY
CAUTION: Do not attempt to recharge a battery with low (or frozen) electrolyte! Doing so risks blowing up the battery if the hydrogen gas inside is ignited by a spark.
Your charging system should be capable of recharging the battery if it is not fully discharged. Thirty minutes or so of normal driving should be enough.
If your battery is completely dead or extremely low, it should be recharged with a fast or slow charger. This will reduce the risk of overtaxing and damaging your vehicle's charging system. One or both battery cables should be disconnected from the battery prior to charging it with a charger. This will eliminate any risk of damage to your vehicle's electrical system or its onboard electronics.
Question:
2. My battery keeps running down. Do I need a new battery?
Answer:
It might, but then again it might not. The only way to know for sure is to (1) test the condition of the battery to see if it is capable of holding a charge, (2) check the output of the charging system to see if it is functioning properly, and (3) if the battery and charging system are okay, check for a possible current drain on the battery when the key is off. In other words, if the battery is okay and the charging system is doing its job, then something is draining voltage from the battery and running it down when the key is off.
One way to check the battery is to recharge it, then let it sit for a day with both battery cables disconnected. If the battery holds the charge and doesn't run down, it's probably okay, and the problem is in your charging system or wiring.
To see if the charging system is working properly, start the car and turn on the headlights. If the headlights are dim, it indicates the lights are running off the battery and that little or no juice is being produced by the alternator. If the lights get brighter as you rev the engine, it means the alternator is producing some current, but may not be producing enough at idle to keep the battery properly charged. If the lights have normal brightness and don't change intensity as the engine is revved, your charging system is functioning normally.
You can also check the charging system by connecting the leads of a voltmeter to the battery. When the engine starts, the charging voltage should jump to about 14.5 or higher. If the reading doesn't change or rises less than a volt, you have a charging problem that will require further diagnosis.
If the battery and charging system seem to be working normally, the only thing that's left is the electrical system. If the battery runs down overnight or when the vehicle sits for several days, it means something is remaining on and drawing current when the ignition is turned off. It may be a trunk light or cigarette lighter that remains on all the time, a fuel pump relay or other relay with frozen contacts that's drawing current, a rear window defroster that doesn't shut off, or a short in the radio or other electrical accessory.
All vehicles draw a little current from the battery when the key is off to run the clock, keep the memory alive in a digital radio (so it doesn't forget the station settings) and the engine computer. Alarm systems need current to keep their circuits armed as do cellular phones.
Current drain on the battery can be checked with an ammeter. Make sure the ignition is off, then disconnect one of the battery cables. Connect one ammeter lead to the battery and the other to the cable. The normal current drain on most vehicles should be about 25 milliamps or less. If the key-off drain exceeds 100 milliamps, there's an electrical problem that requires further diagnosis.
Finding the hidden current drain can be time consuming. The easiest way to isolate the problem is to pull one fuse at a time from the fuse panel until the ammeter reading drops. This will tell you which circuit is draining the battery. Then you have to check the wiring and each of the components in that circuit to pinpoint the problem.
Question:
3. How can I tell if my battery is good or bad?
Answer:
The condition of the cell plates inside the battery determines whether or not a battery is still serviceable. Current is produced when sulfuric acid in the battery reacts with lead in the cell plates. As the battery discharges, sulfate accumulates on the plates and reduces the battery's ability to make current. The sulfate is returned to solution when the alternator recharges the battery by forcing current to flow in the opposite direction.
Over time, some of the sulfate becomes permanently attached to the plates. The sulfate forms a barrier that diminishes the battery's ability to produce and store electricity. This process can be accelerated if the battery is run down frequently or is allowed to remain in a discharged state for more than a few days. If the plates have become sulfated, therefore, the battery won't accept a charge and will have to be replaced.
Average battery life is only about four to five years under the best of circumstances -- and sometimes as short as two to three years in extremely hot climates such as Arizona and New Mexico. But the battery may become "sulfated" prematurely if it is chronically undercharged (charging problems or frequent short-trip driving), or if the water level inside the battery drops below the top of the cell plates as a result of hot weather or overcharging and allows the cell plates to dry out.
BATTERY TESTING
This is something you can't really do yourself, so you need to take your vehicle to a service facility that has the proper test equipment. The battery's condition can be determined one of two ways: with a carbon pile "load test" (that applies a calibrated load to the battery) or electronically with a special tester that measures the battery's internal resistance.
Equipment that uses a carbon pile for load testing requires the battery to be at least 75% charged. If the battery is less than 75% charged, a good battery may fail the test. So the state of charge must be checked first, and the battery recharged if it is low prior to testing. NOTE: The battery does NOT have to be fully charged prior to testing if an electronic tester that measures internal resistance is being used.
If load testing with a carbon pile, apply a load that is equal to half the battery's cold cranking amps (CCA) rating. A good battery should be able to supply half its CCA rating for fifteen seconds without dropping below 9.5 volts.
Question:
4. Does a replacement battery need to be the same size as my old one?
Answer:
No. If your old battery has reached the end of the road and needs to be replaced, or if you think you need a battery with a bigger amp capacity for easier cold weather starting or to handle added electrical accessories (such as a killer stereo system, driving lights, etc.), then there's no reason why you have to install a battery that's the same size as your old one.
The word "size" may be a bit confusing here because what we're really talking about is the battery's amp or power rating, not the physical dimensions of its case.
A battery with a bigger case is not necessarily a more powerful battery. Battery manufacturers can cram a lot of amps into a relatively small box by varying the design of the cell plates and grids. So two batteries with identical exterior dimensions may have significantly different power ratings.
Batteries come in many different sizes and configurations (which are referred to as "group" sizes) because the vehicle manufacturers can't get together and standardize anything. So when you're choosing a battery, you have to consider three things: (1) the group size (height, width, length and post configuration), (2) whether your battery has top or side posts, and (3) how many amps will be needed for reliable cold starting and vehicle operation.
GROUP SIZES
Because there are 57 different group sizes, many aftermarket replacement battery suppliers consolidate group sizes to simplify inventory requirements. So some replacement batteries may not fit exactly the same as the original. The battery may be slightly shorter, taller, narrower or wider than the original. But as long as it fits the battery tray and there are no interference problems (too tall a battery may cause the cables to make contact with the hood causing a dangerous and damaging electrical short!), it should work fine.
Some replacement batteries come with both side and top posts to further consolidate applications. Some also have folding handles to make handling and installation easier.
BATTERY RATINGS
Though many replacement batteries are marketed by the number of "months" of warranty coverage provided (36, 48, 60, etc.), what's more important in terms of performance is the battery's power rating which is usually specified in "Cold Cranking Amps" (CCA) rating. The CCA rating tells you how many amps the battery can deliver at 0 degree F. for 30 seconds and still maintain a minimum voltage of 1.2v. per cell.
In the past, the rule of thumb was to always buy a battery with a rating of at least one CCA per cubic inch of engine displacement. But twice that is probably a better recommendation for reliable cold weather starting.
At the very least, you should buy a replacement battery with the same or better CCA rating as your old battery or one that meets the vehicle manufacturer's requirements. For most small four-cylinder engines, this would be a 450 CCA or larger battery, for a six cylinder application, a 550 CCA or larger battery, and for a V8 a 650 CCA or larger battery. Bigger is usually better. Extra battery capacity is recommended if your vehicle has a lot of electrical accessories such as air conditioning, power windows, seats, electric rear defogger, etc.
BATTERY INSTALLATION
Most batteries are "dry charged" at the factory, which means they're activated as soon as acid is poured into the cells. Even so, the battery may require some charging to bring it all the way up to full charge.
Most experts recommend charging the battery before it is installed regardless of whether it is dry charged or not. This will ensure the battery is at full charge and lessen the strain on your charging system.
When the battery is installed, it must be locked down and held securely by a clamp, strap or bracket. This will not only keep the battery from sliding around on its tray (which might allow the positive cable to touch against something and short out the battery or start a fire!), but will also help to minimize vibration that can damage the battery.
The battery cables should also be inspected to make sure they're in good condition, too. If the cables are badly corroded, don't fit the battery posts or terminals tightly, or have been "fixed" by installing temporary clamps on the ends, the cables should be replaced. At the very least, you should clean the cable clamps and battery posts with a post cleaner, sandpaper or a wire brush to ensure good electrical contact. A light coating of grease, petroleum jelly and/or installing chemically treated felt washers under the cable clamps will help prevent corrosion.
Question:
5. Is there any danger to me or my vehicle if I give someone a "jump start?"
Answer:
Yes. The danger to you is a battery explosion. Batteries contain hydrogen gas, which can ignite and explode if a spark occurs anywhere near the battery. Batteries also contain acid which may be splashed on you if the battery explodes.
The danger to your vehicle is if someone reverses the jumper connections or touches the jumper cables together. The voltage surge that results may damage your charging system and/or other electronic components in your vehicle.
To minimize these risks, use the following procedure when jump starting :
- Do not smoke. You should also wear eye protection.
- Make sure the vehicles are not touching (contact could provide an unwanted electrical path).
- Turn your engine off.
- Connect the red jumper cable from the positive (+) post or terminal on your "good" battery to the positive post or terminal on the low or dead battery in the other vehicle.
- Connect the black jumper cable from the negative (-) post or terminal on your good battery to a solid ground on the other vehicle.
CAUTION: DO NOT make the final jumper connection directly to the low or dead battery itself.
The reason for not doing this is because the final jumper connection usually produces a spark. Making the final connection away from the battery will minimize any danger of an explosion by keeping the spark well away from the battery.
- Make sure the ground connection on the vehicle with the low or dead battery provides a good electrical contact. Use an unpainted metal surface like an engine bracket or a frame member.
- Make sure the cables do not touch each other and that the cables are clear of the fan and pulleys on both vehicles.
- Start the engine in the vehicle with the good battery. Run the engine at fast idle for several minutes before attempting to start the vehicle with the low or dead battery. This will allow the charging system to pump some life into the other battery lessening the drain on the good battery and charging system.
- As soon as the vehicle with the dead battery starts, disconnect the battery cables. The vehicle should then be run or driven at least thirty minutes to recharge the low or dead battery. Additional charging time may be required depending on the battery's condition and state of charge.
If the vehicle does not crank or cranks slowly, recheck the jumper connections. If it still doesn't crank, the problem may be something other then the battery (such as a bad starter, solenoid, battery cable connection or internal engine problem).
If the vehicle cranks normally, but refuses to start, it may have an ignition, fuel or mechanical problem.
Do not crank the starter more than thirty seconds at a stretch. Allow the starter to cool for about two minutes before cranking the engine again. Continuous grinding of the starter can cause it to overheat and fail. Continuous cranking can also sap the juice out of your good battery and/or overload and possibly damage your charging system, too!
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