A/C COMPRESS. OVAL O-RING SEAL DESIGN INFO. W/R4,HR6,V5

VEHICLES AFFECTED: ALL 1988-90 CARS AND TRUCKS W/R4, HR6 AND V5 A/C COMPRESSORS

During the 1988 model year,approximately June 1,1988,the cross section design of the A/C compressor O-rings was changed from the standard round type to an oval type design.

The reason for the design change was to improve the durability of the compressor refrigerant joint.

It is important to understand, that due to the cross section shape of the oval verses the round design (see Fig.2), the oval O-ring does not completely fill the machined O-ring groove in the compressor rear head (see Fig.1). A gap between the oval O-ring inside diameter and the machined groove inside diameter is correct and expected.

In addition, the oval O-ring does not fit freely in the O-ring groove. The O-ring must be coated with approved refrigerant oil and inserted all the way into the O-ring groove prior to the joint assembly.

The service part numbers for the oval O-rings are shown in both Fig.2 and Fig.3.

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.