A/C NOISE/VIBRATION NEW PART AND PROCEDURE

AIR CONDITIONING NOISE/VIBRATION

VEHICLES AFFECTED: 1987-88 M-VAN W/AIR CONDITIONING WITH 4.3L ------------------ ENGINE (VIN CODE Z)

Some 1987-88 M-vans equipped with 4.3L engines may exhibit a noise/vibration when the air conditioning compressor is engaged. This noise is the result of a resonance set up in the serpentine accessory drive system with air conditioning on.

This condition, if experienced, may be repaired by installing a brace kit, P/N 10129506.

It is recommended that the air cleaner assembly be removed and the negative battery cable be disconnected prior to installing the brace kit.

NOTICE: THE FOLLOWING STEPS SHOULD BE TAKEN TO ASSURE PROPER INSTALLATION AND FUNCTION OF THE BRACE KIT.

1. The A/C pipe mounted behind the generator should be moved as required to gain adequate clearance for installation of the three braces. See Illustrations. Do not crimp the pipe.

2. Install braces per instructions in kit.

3. The clamp that supports the A/C pipe behind the generator should be repositioned as shown in the Illustrations and reattached to the generator. The A/C pipe may need to be repositioned to fit the new clamp location.

4. Finally, with kit installed, inspect for adequate clearance in the following areas:

A. Between the A/C pipe behind the generator and the battery connection to the generator (approximately 1/2 inch is adequate clearance).

B. Between the A/C pipe and the engine lift bracket,

C. Between the A/C pipe and the brake vacuum booster.

D. Between the A/C pipe and upper radiator hose.

The A/C pipe must not be in contact with any of the above mentioned components. Move the A/C pipe as required to provide adequate clearance.

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.