Engine Accessory Drive Test

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 a 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.