Maintenance Definitions
QUESTIONS
ANSWERS
  1. Accessory Belts

    Belts are used to drive the accessories on an engine (e.g., the alternator, air conditioning, power steering, etc.) Most engines now use serpentine belts rather than V-belts, that were used years ago. Serpentine belts give much less problems, but do still need to be replaced.

    Accessory belts are on the outside the engine and are easily inspected. Belts that are frayed, cracked or glazed need replacement, as they can break and cause engine damage. Also belts that squeal may be candidates for replacement.

    Most newer vehicles use belts made of EPDM, a very tough material that does not crack. These belts must be checked for wear, with a gauge, made for the purpose. When these belts wear, they may slip and create a great deal of heat and damage driven components.

    Under normal conditions, accessory belts last between 50,000 and 65,000 miles. EPDM belts may last even longer, but should be replace after seven years are when indicated by a wear gauge.

    Accessory belts should not be confused with the timing belt, which is internal to the engine. Timing belts are covered in their own section.

    For more information on belt inspection, please see our Detailed Topic, Symptoms of A Bad Serpentine Belt and EPDM Belts.


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  2. Air conditioner condenser

    Not often considered as a maintenance item, cleaning the air conditioner condenser can greatly extend the life of the system. Condensers are exposed to air flow and tend to collect bugs and dust. Gently hosing the debris from the condenser with a hose may help lower compressor head pressure and increase efficiency. Air conditioner condensers should be cleaned annually, best before the start of summer.
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  3. Air Filter

    Engines run on fuel, but they also use air. In fact they use 14.7 times more air than fuel. Unfortunately even clean air still contains a lot of minute dust particles. The air filter attempts to remove these particles before they enter the engine. In time the filter becomes clogged and the air flow will become restricted. When this happens the engine loses power. Contrary to common belief and advertising, even a badly restricted air filter will not reduce fuel mileage.

    The best air filter to use is the one supplied by your vehicle manufacturer. Substandard air filters can have poor seals and filter media. These faults can drastically increase wear to the cylinders and also damage air flow meters. The life of the air filter depends on the amount of dust in the air that passes through it. In very dusty areas they can become clogged in as little as 5,000 miles. Under normal conditions they should last 30,000 to 50,000 miles or more. Vehicles that have indicators on the filter housing can also use that as a guide. Care must be taken when replacing the filter. Debris that can fall from the filter can easily be drawn into the engine. Carelessly replacing the air filter can actually cause far more problems than the old air filter.

    For more information, please see our Detailed Topic When Should Air Filters Be Replaced.


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  4. Automatic transmission service

    Automatic transmissions produce debris as part of their normal operation. Metal particles and clutch material are worn from their original parts and circulate with the fluid until removed by the filter. The fluid also loses some of its properties over time, from continual exposure to heat and use.

    Most automatic transmissions have a removable filter. With proper service on these units, the pan is removed, the old fluid drained and the filter is replaced. In many instances the valve body bolts may be tightened to specifications and the bands adjusted if so equipped.

    We recommend this service at three years or 50,000 miles, whichever occurs first. On other units [Honda, some Mazda, some Ford, etc.] replacement of the internal filter may require disassembly of the transmission. On these models service is performed by draining and filling the unit, twice in succession if needed.
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  5. Batteries

    Batteries are not often thought of as maintenance items. Instead many folks wait until they fail before replacing them. This can lead to a very inconvenient situation and over work the charging system as well. Batteries suffer 100% mortality and most die between three and four years. Some die suddenly and can leave the vehicle stranded. Others die slowly and cause the alternator and starter to work much harder

    Since all batteries die, many folks find it more convenient to replace them before this occurs. Three-years is a pretty safe guideline in South Louisiana. Some last longer, but their low cost and unpredictable nature makes trusting them considerably longer pretty cost ineffective.
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  6. Brake fluid

    Most brake fluid is made of alcohol and absorbs moisture from the atmosphere. Moisture content will lower the boiling point of the fluid and increase corrosion to the system. This occurs 24 hours a day and whether the vehicle is driven or not. For this reason, time is a better indicator of when to change rather than miles.

    Color is not a reliable indicator of moisture content. Some fluids that are clear may be contaminated and others that are dark may be okay. Brake fluid can be tested with a refractometer, to reveal it’s moisture content. Without such an instrument a good rule of thumb would be every two to three years and before any brake service.
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  7. Cabin filter

    The cabin filter or heating, ventilation and air conditioning (HVAC) filter is an often overlooked maintenance item. Though some vehicles have had these since the early nineties, many vehicle owners are not familiar with them.

    The cabin filter is much like the air conditioner inlet filter in your home. It removes dust and debris from the air before it is circulated through the evaporator and heater cores. When they become restricted, the fan may draw too much amperage and damage the circuitry or even the automatic temperature control assemblies if so equipped.

    Not all vehicles are equipped with cabin filters but many are. They are normally replaced every 15,000 miles. If you are not certain check your vehicle owner's manual.
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  8. Coolant/Antifreeze

    Coolant, also called antifreeze performs several functions. To perform these functions it is mixed with water. In South Louisiana the proper mixture is 50/50 or half coolant and half water. The water performs the engine cooling function. Since water freezes at 32 degrees Fahrenheit, the addition of antifreeze is necessary to lower the freeze point. When water freezes it expands and this expansion can crack an engine block and cause severe damage. Antifreeze lowers the freeze point below that which is likely to occur.

    An even more important function is corrosion protection. Coolant works in several ways, depending on its makeup to prevent corrosion. There are several types of coolant each using a different methods of protection. Many are not compatible with one another and it is always advisable to stay with the type of coolant specified by the vehicle manufacturer.

    Over time the corrosion inhibitors are depleted leaving the cooling system unprotected. New coolant has reserve alkalinity and a pH of 8.0 or higher. As coolant ages, pH tends to fall and the coolant becomes acidic, causing severe damage. The protection against freezing is also lost over time.

    The change interval for coolant is more dependent on time than miles. Because it is a chemical reaction, it occurs 24/7, whether the vehicle is driven are not. To be safe it is normally replaced every two to three years, when the pH approaches 7.0 or when the specific gravity indicates an insufficient freeze point.

    Please see our Detailed Topic Symptoms and Causes of Cooling System Problems for a lot more information on coolants and corrosion.


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  9. Differential fluid

    Differential fluid lubricates the gears, bearings and if present clutches of the differential. A differential is necessary to transmit power to the drive wheels of the vehicle. The input from the transmission passes through the gears of the differential. Here the direction of force is changed and applied to the drive wheels. The churning of these gears through the lubricant produces pressure. This pressure is vented to the atmosphere. The same vent allows moisture to enter the system. The fluid, not only lubricates, cools and cleans the gears, it also suspends any moisture that enters the system.

    In time the lubricant breaks down and becomes dirty. On many front wheel drive vehicles the differential is part of the transmission. It is serviced when the transmission is serviced. On rear wheel drive and all vehicles with a separate differential, it needs to be serviced separately. This is often recommended around 50,000 miles, but may be as low as 15,000 when towing or as high as 100,000 in some cases.
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  10. Fuel filter

    The fuel filter removes impurities that are in the fuel. Impurities enter fuel in transport and shipping and in the storage tanks at fuel stations. They can also come from rusted or deteriorated fuel tank linings in vehicles.

    A small amount of trash can ruin fuel injectors, fuel pressure regulators and even damage an engine. Fuel filters should be replace about every 45,000 to 60,000 miles, unless they are mounted in the fuel tank. Fuel filters, that are located in the tank, are normally good for about 100,000 miles

    Fuel filters should also be replaced whenever there is a fuel system problem, like fuel pump failure or contaminated fuel enters the system.
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  11. Hoses

    Coolant hoses are much better today than they were a few years ago. Many last ten years are more. The hoses that come on a new vehicle may also be better than the replacements that are available.

    Because of the high quality of the original hoses, it is often best to have them inspected, and replace only when needed. Inspection should be at three years and every year there after. Replace hoses when they are found to be swollen, soft, hardened, cut, frayed or when inspection shows need for replacement.

    There are also power steering hoses and air conditioner hoses. With these too, inspection is the better policy and replace as needed, rather than at specific time intervals.
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  12. Maintenance Defined

    Maintenance is service performed and parts replaced to reduce greatly the odds of more expensive components failing. For instance coolant is replaced in the hope of preventing corrosion damage to radiators, heater cores and engines. The cost of the coolant replacement is a fraction of the cost of the repairs it can prevent.
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  13. Manual transmission fluid

    The lubricant used in a manual transmission gets dirty, can absorb moisture and suffer diminished properties over time. Debris is produced by the gears, bushings and moving components. Almost no manual transmissions contain filters and replacing the fluid is the only way to remove debris that accumulates.

    As a general rule we recommend manual transmission fluid replacement between 50,000 and 100,000 miles, more often when towing. It is important to remember transmissions use many different types of lubricants today. Always check with service for the proper type before replacing transmission fluid.
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  14. Pack wheel bearings
    Many new vehicles use sealed wheel bearings that cannot be serviced. On others, bearings need to be removed, cleaned, packed with fresh grease and the seals need to be replaced. On some vehicles the front bearings are able to be packed and on others vehicles the rear may be serviceable as well.

    On vehicles with bearings that can be packed, the service is normally performed at each brake service or around 50,000 miles.

    See our Detailed Topic article Adjusting Wheel Bearings for far more details.
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  15. PCV Valve

    The positive crankcase ventilation or PCV valve, removes fumes and pressure that is generated in the engine. In time the PCV valve may plug up. When this occurs pressure may start to build. Pressure buildup can damage oil seals and gaskets and they often blow out, resulting in oil leaks.

    Under normal use the PCV valve should be replaced about every 80,000 to 100,000 miles but can fail as often as 50,000 miles. They should also be tested whenever engine service is performed and replaced sooner if needed.

    For more information, please see out Detailed Topic What are the symptoms of a bad PCV valve.


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  16. Power steering fluid

    Power steering fluid comes in several different types. Most vehicles use a hydraulic oil, but some vehicles use automatic transmission fluid and still others a vehicle-specific fluid. Power steering fluid acts as a lubricant, cleaner, seal conditioner, coolant and hydraulic fluid for the system.

    Like most fluids, in time, power steering fluid loses the properties that help it to work. It also becomes laden with debris and since most systems do not have a filter, it must be replaced. Replacing power steering fluid between 50,000 and 100,000 miles is normally adequate, unless recommended sooner by the manufacturer. Though not the main intent, properly replacing power steering fluid may also help with power steering noise as well.

    For more information, please see our Detailed Topic How To Replace Power Steering Fluid.


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  17. Spark plugs

    Spark plugs provide a small (0.03" - 0.90") gap that generates a spark, when electrical current jumps across it. This spark in turn ignites the compressed fuel-air mixture. The combination of extreme heat and high voltage cause the electrodes, that form the gap to wear. As they wear the gap gets wider and the plugs no longer fire as efficiently as before.

    Depending on the construction of the spark plug, they normally wear out between 30,000 and 100,000 miles. Standard spark plugs wear out closer to the minimum and platinum and iridium plugs closer to the maximum listed.

    Worn plug on left, new plug on right.

    It is also important to consider that spark plugs are made unusable in other ways than just the gap. They can become fouled, or the electrodes covered with foreign matter. They can also leak between the ceramic and the base.

    For more information, please see our Detailed Topic When Do Spark Plugs Need To Be Replaced.


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  18. Timing belts

    Many engines have an internal timing belt. This is different from the external accessory or serpentine belts. The timing belt drives the camshaft(s) and cannot be readily inspected. There are specific recommendations for timing belt replacement, given by manufacturers. Timing belt replacement is normally recommended between 60,000 and 105,000 miles, depending on design.

    Because access is difficult, other wear items, in the area of the timing belt, are often replaced with the timing belt. The belt idler pulley(s), front crankshaft and camshaft seal(s), water pump, etc. may be suggested. The reason for this suggestion is these other parts do fail, and the cost of replacement is much less, while the timing belt is off.

    There is a great deal of price difference, between a complete job and merely replacing the belt. Iit is wise to know exactly what is being charged for when replacing a timing belt.

    For more information on timing belts see our article All About Timing Belts.
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  19. Tires

    Tires wear out in time and the tread becomes thin. This is not the only way that tires fail. Tires also have a life expectancy of six-years. As tires age, the adhesives that hold them together as well as the rubber they are constructed of, deteriorates. When this happens, they can separate and blow out.

    Tires must be inspected for age, as well as cuts, bulges and wear to the tread. Tires should be replaced when tread depth reaches 2/32 inch or when the age reaches six-years. Age can be determined by the DOT number that will be imprinted on the sidewall. The last four digits show the week and year of manufacture.

    To learn how to read a tire date code, please see How to read a DOT number.


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  20. Transfer case fluid (4WD only)

    The lubricant in a transfer case gets dirty, can absorb moisture and suffer diminished properties over time. Debris is produced by the gears, bushings, chain and moving components. As a general rule we recommend transfer case fluid replacement between 50,000 and 100,000 miles, more often when towing. Transfer cases, like transmissions often use a specialized lubricant. Service data should always be consulted before replacing transfer case fluid on any four-wheel drive vehicle.
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