A/C REFRIGERANT LOSS DUE TO LOOSE OR MISSING ACCESS CAPS

SUBJECT: A/C REFRIGERANT LOSS DUE TO LOOSE OR MISSING ACCESS FITTING CAPS

MODELS: 1980-91 TRUCKS WITH A/C

THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 91. DATED JULY 1991. ALL COPIES OF 91-1B-112 SHOULD BE DISCARDED

This bulletin is being revised to add 1990-91 model years and to update a discontinued part number for high side valve-cap and seal.

All GM 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.

If the cap and seal assembly is missing or loose, a significant amount of refrigerant may leak through the valve core located in the access fitting, which could result in poor A/C performance or failure.

When servicing any vehicle's A/C system, make sure all access fitting cap seals (refer to Figure 1) are in place and tight. Caps should be threaded on until contact with the "O" 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 Valve- Cap and Seal 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.