For 1990-2009 cars

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

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. This O-ring can also be used on past model compressors.

It is important to understand that due to the cross-section shape of the oval versus the round design (refer to Figure 1), the oval O-ring does not completely fill the machined O-ring groove in the compressor rear head. Refer to Figure 2. 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 Figure 1. Parts are currently available from GMSPO.

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.