Drive Belt Tensioner: Testing and Inspection

The automatic drive belt tensioner can be checked as follows:
1. With the engine running, observe drive belt tensioner movement. The drive belt tensioner should move (respond) when the A/C compressor 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 rideout (uneven depth of grooves in drive belt) 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.
2. With engine OFF, check for proper routing of the drive belt. Service as required.
3. Inspect the drive belt tensioner wear indicator as described under Drive Belt Tensioner, Automatic in Adjustments to make sure the drive belt is within operating range. Replace the drive belt as required.
4. Rotate the tensioner from its relaxed position through its full stroke and back to the relaxed position. Check that there is no sticking, grabbing or binding. Check that there is tension on the tensioner spring.