What do a dead battery, a squealing noise, and repeated engine problems all have in common?
The answer is a bad serpentine belt tensioner that may cause each issue. Often the cause of these problems is hard to find.
Typical serpentine belts route around numerous drive accessories and components used on your motor. Manufacturers design serpentine belts to drive accessories on the engine such as the air conditioner compressor, alternator, and power steering pump. The name serpentine comes from the way the belt snakes around the engine. The serpentine belt wraps around a pulley connected to the engine's crankshaft damper. This is the main drive pulley for the engine's serpentine belt. It also wraps around pulleys located to each accessory. A constant rate of friction is required for the serpentine belt to operate correctly. Engineers create this friction by the material used to make the belt and the belt tensioner that holds it tightly against the pulleys. Manually adjustable belt tensioners were common on older vehicles.
This type of belt tensioner required periodic adjustments to maintain the required tension. Today most modern vehicles use spring-loaded automatic serpentine belt tensioners. The serpentine belt automatically applies tension to the belt, keeping it tight against the pulleys. The main advantage offered by a belt tensioner assembly is that it applies a constant rate of tension at all operating temperatures and conditions.
Maintenance of the belt tensioner assembly is vital for proper engine operation. The regular inspection of the serpentine belt tensioner is a smart practice. Address the issue as soon as your serpentine belts show signs of wear, slipping, squeaks, or chirps are heard.