How Serpentine Belt Tensioners Work

Step by step guide on how a serpentine belt tensioner works, this information pertains to most vehicles.

Step 1 - A serpentine belt tensioner is designed to hold a prescribed amount of tension to ensure the proper operation of the serpentine belt, the tensioner is comprised of a housing, spring, idler pulley w/bearing, pivot and mounting bolts.

Serpentine Belt Tensioner

Step 2 - In time, the pivot bulkhead will wear allowing the belt to become misaligned which results in belt operation failure, the tensioner must then be replaced.

New Serpentine Belt Tensioner

Step 3 - A tensioner can be designed many different ways including having heater hoses included within the unit.

Heater Hose Designed Tensioner

Helpful Information

There are many configurations of belt tensioners but all follow the same principle. When these units wear they allow the belt to squeal and pop with eminent failure in the near future. These units are non-adjustable and require no maintenance expect for replacement. Some tensioners feature a replacement pulley separate from the housing a spring assembly.