Drive Belt Tensioner: Testing and Inspection

With The Engine Running
Observe drive belt tensioner movement with the engine running. The drive belt tensioner should move (respond) when the A/C compressor (19703) cycles or when the engine is accelerated rapidly. If the drive belt tensioner movement is constant and excessive, a pulley or shaft is probably bent or a pulley is out of round. In rare cases, excessive drive belt ride out (uneven depth of grooves in drive belt (8620)) can cause excessive drive belt tensioner movement. This condition can be checked by replacing the suspect drive belt with a new drive belt and repeating the observation.

With Engine OFF
1. Check for proper routing of the drive belt. Service as required.
2. Inspect the drive belt tensioner wear indicator to make sure the drive belt is within operating range. Replace the drive belt as required.
3. Rotate the tensioner from its relaxed position through its full stroke and back to the relaxed position. Check that there is no sticking, grabing or binding. Check that there is tension on the tensioner spring.
4. Automatic drive belt tensioners have drive belt wear indicator marks. If the indicator mark is not between the MIN and MAX marks, the drive belt is worn or an incorrect drive belt has been installed. If the indicator marks are difficult to see, locate the tab on the drive belt tensioner face plate. The tab should be approximately between the stops.