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.
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.