Car Maintenance Guide
Belts

People often wait until they get some indication that their vehicle needs service - such as a noise or squeal - before taking it to a repair facility. Although you should have a professional technician look at your belts and hoses as part of your regular maintenance schedule, basic inspection can be done on your own. By conducting monthly inspections of your belts, you can help prevent premature engine wear and extend the life of your vehicle.

Types of Belts

Serpentine Belts:

Serpentine belts are more commonly found on modern vehicles. They can be identified by their small thickness and wide surface area. On most vehicles that have a serpentine belt, it will drive most, and in many cases all, of the accessories.

V-Belts:

V-belts are named for their appearance. They have a relatively narrow outside surface, then get thicker before tapering down. With V-belts, it is common for vehicles to have multiple belts driving the accessories.

Timing Belts:

The timing belt is the connection between the engine's crankshaft and camshaft. You cannot see the timing belt because it is encased behind the front engine cover. As the toothed timing belt rotates around the crankshaft and camshaft sprockets, it maintains the proper timing of these major engine components. On certain types of engines the timing belt may also drive the water and oil pump, or a balance shaft. Not every engine has a timing belt. Some engines have timing gears or a timing chain.

The timing belt can fail just like the alternator or air conditioning drive belts. However, it has one major difference * if the timing belt breaks or slips, the engine may not run at all and it could cause serious internal engine damage. Some vehicles have clearance built into the engine components, so that when a malfunction of the timing belt occurs, it will not cause internal engine damage. This is called a non-interference engine. Vehicles that can have serious damage to internal engine parts when the timing belt malfunctions are called interference engines. Common problems caused by a broken or slipped timing belt on an interference engine are bent valves and piston damage. These types of repairs are costly, but you can do something to help prevent this from happening. Manufacturers have estimated the life expectancy of these belts and offer recommended intervals for replacing these belts. Refer to the owner's manual for your vehicle's timing belt care and recommended replacement intervals.

Belt Inspection:

1. Check your vehicle's belts before you start your car, while the engine is still cold. This will help avoid the possibility of an accidental burn from a hot engine component or an injury caused by a moving part of the engine.
2. Carefully inspect the belts along their edges and undersides for any signs of wear (see "Visual Signs of Wear" below). These danger signs indicate a belt may need to be replaced or that a belt-driven component may be failing.
3. Belt tension should be checked and adjusted on a regular basis. If the belt tension is too tight, it can cause bearings in the accessory components, and even in the engine itself, to wear prematurely. If it is too loose, the belt will slip and squeal, causing the accessory components to work less efficiently. Inadequate tension also will cause the belt to wear excessively. The most accurate way to check tension is with a belt tension gauge, but you can estimate correct tension by pressing on the belt along its longest straight section. If the tension is correct, the belt will only have about 1/2 inch to 1 inch of play.
4. Drive belts are necessary to operate the accessory components attached to the engine, such as the alternator, power steering pump, air conditioner compressor and the water pump. To fully assess the condition of the belts, do a visual inspection and test the belt tension.

Visual Signs of Wear

• Glazing: The side or contact area of the belt becomes slick and shiny when a loose belt slips in the pulley. The glazed belt can no longer grip adequately and the belt slips even more. Grease and oil on the pulley can also cause glazing.
• Oil-soaked: Grease, oil and other engine fluids on the belt or in the pulley grooves will glaze the belt and increase slippage. The fluid contamination may also deteriorate the belt.
• Pilling: The belt's rubber compound wears off and builds up on the drive pulleys (the wheel that is driven by or drives the belt). Lack of tension, misalignment, or worn pulleys can cause this condition.
• Cracks