Some vehicles have two drive belts, but most modern veh […]
Some vehicles have two drive belts, but most modern vehicles have a single belt, called a serpentine belt. It’s a reinforced, ribbed rubber belt that delivers power to your alternator, air conditioning, power steering, cooling system, and other components in your vehicle. Usually, these belts don’t require maintenance, and will last up to 150,000 miles. Of course they’re not going to last forever, and once they fail, your vehicle isn’t going to go anywhere.
To work properly, a drive belt must be under proper tension. In older cars, belt tension had to be adjusted manually, see the photo. Typically, you would hear a loud screeching noise when the engine is started if the drive belt is loose. In cars with manual adjustment, the belt tension must be checked during regular services and adjusted as necessary.
Noisy drive belt is the biggest tip off that you have a drive belt problem that shouldn’t be ignored. If your serpentine belt is squealing, it’s time for an inspection. If the squeak is due to leaking or spilled motor oil, that’s a whole other ball game. Oil is the kiss of death to the belt, so make sure you don’t have any leaks, and have Your Mechanic replace the belt right away, instead of waiting until the inevitable damage forces you to have it done. Before your belt fails, it will usually show signs of wear. Many belts will function quite well with a few bits missing.
A number of factors can cause a drive belt to wear prematurely. For example, in this car, in the photo, a drive belt needed to be replaced every three months. Upon closer inspection, we found that the alternator was installed improperly, under angle. Click on the photo to see the larger image. This caused the alternator pulley to be misaligned with the belt, so the belt was wearing out faster.
A damaged or missing engine undershield can also cause a drive belt to wear faster. An undershield protects the belt from dirt, sand and water. If the undershield is missing, water and small rocks can get under the belt and wear it faster. Improper tension, oil and coolant leaks can also cause the Rubber Drive Belts to wear faster.