Some vehicles may exhibit a condition of inoperative or poor A/C performance. This condition may be caused by a loose or missing cap and seal assembly, which results in the loss of a significant amount of refrigerant through the valve core located in the access fitting.
Air conditioning High side and Low side access fittings are supplied with a black plastic cap and seal assembly which provides the primary refrigerant seal for the service fittings.
When servicing or leak checking any vehicle's A/C system, make sure all access fitting cap seals are in place and tight. Refer to Figure 1. Caps should be threaded on until contact with the 0-ring seal is made and then tightened another 1/4 - 1/2 turn to ensure proper sealing.
High Side Low Side --------- -------- Valve-Cap and Seal (3/8 x 24) Valve-Cap and Seal (5/16 x 20) P/N 52451233 P/N 6551640
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.