Engine Accessory Drive Test

To carry out this test, proceed as follows:
^ Remove the accessory drive belts.

WARNING: BLOCK THE FRONT AND REAR WHEELS, AND APPLY THE PARKING BRAKE AND THE SERVICE BRAKE, OR INJURY TO PERSONNEL CAN RESULT.

CAUTION: Limit engine running time to one minute or less with belts removed or serious engine damage will result.

NOTE: A serpentine drive belt decreases the usefulness of this test. In these cases, use the Vibration Analyzer (VA), to pinpoint accessory vibrations. An electronic listening device, such as an EngineEAR, will also help to identify noises from specific accessories.

^ Increase the engine rpm to where the concern occurs.
^ If the vibration/noise is duplicated when carrying out this test, the belts and accessories are not sources.
^ If the vibration/noise was not duplicated when carrying out this test, install each accessory belt, one at a time, to locate the source.