How to Maintain a Serpentine Belt

Most modern cars use a single serpentine belt to run the accessories including the water pump, the alternator and the power steering. This belt should be good for about 50,000 miles, but if it fails, the car will be undrivable. To maintain the belt, check it periodically for wear, cracking and proper tension. Here's what to look for.

Instructions

1. Listen for any noise from the belt with the engine running. Serpentine belts generally don't slip, but a squealing noise could mean the belt tensioner or one of the pulley's bearings are going bad.

2. Visually examine the belt with the engine off. Some cracking on the outer surface is normal as the belt ages, but if there is an average of 10 cracks per linear inch, it's time to replace it.

3. Turn the belt with your fingers to look at the inner surface. If some of the tracks are broken or missing, or if there are any tears, replace the belt.

4. Check the belt's tension by pressing down on it between the pulleys. You should only feel a slight give. If the belt seems loose or if there is no give at all, the problem could be the belt tensioner. The tensioner is a spring-loaded pulley that keeps constant tension on the belt as it stretches with age, and it's easy to overlook as a source of trouble.

5. Replace the tensioner if it is not working properly, and, since you have to remove the belt to do this, replace it too, if it shows any signs of wear.