For 1990-2009 cars

# INFO ON AVAILABLE DIAGNOSTIC AIDS 4.5L 4.9L DRIVE NOISE

#### SUBJECT: 1990-1992 4.5L, 4.9L ACCESSORY DRIVE NOISE DIAGNOSIS

Many dealers have had great success diagnosing engine and accessory drive noises using a series of special length serpentine drive belts which allow the engine to be operated temporarily with each of the driven accessories inoperative. A kit containing one each of these special length belts is available from Kent-Moore under J-36312 for all 1985-1989 engines. (These engines incorporate an AIR pump in the accessory drive.) Now available is a similar set of belts for 1990-1992 engines without the AIR pump. Dealers may order this kit J-39429 using the attached order form.

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General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.