A/C COMPRESSOR NOISE LOOSE DUST COVER SCREWS

VEHICLES AFFECTED: All 1985 Oldsmobile, Buick and Cadillac or 'C' Models

Reports have been received of medium pitched whine occurring over a wide range of engine rpm's. This noise is most pronounced between 900 and 2100 rpm's on the V-6 engines. The condition is more pronounced in city type driving in hot weather where high A/C head pressures exist.

A compressor built before build code 29054X could have loose dust cover screws. The compressor build date can be found on the upper right hand corner of the compressor label as a 'code number'. The first two digits are the day of the month. The second two digits are the month of the year. The fifth digit is the year (eg. 4=1984). Disregard the sixth digit.

On compressors that exhibit this noise the recommended fix is to torque the (3) screws holding the dust cover to the driver plate to 30-40 in. lbs. (3.3-4.5 N.m). Reference Figure 1 shows the location of these (3) screws. The compressor does not need to be removed from the vehicle to retorque these screws.

If retorquing the screws does not solve the problem, the noise may be confused with a moan type noise occuring at about 1700 engine rpm's. This moan is clutch related and is covered in bulletin 1-101 dated October 31, 1984.

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.