This bulletin is being revised to add the 1992 model year and the IMPORTANT note after paragraph 3. Please discard Bulletin No. 91-1-1.
All 1991-92 Regal and Century models are equipped with a new A/C high pressure service port assembly. The A/C low side pressure service port will remain the same.
The new A/C high pressure port (Figure 1) is not designed with a depressor pin, compared to the older port (Figure 2) which has a depressor pin. The new A/C high pressure port will require the use of two special tools for servicing.
Tool J-38702 is a straight adapter which allows existing diagnostic equipment to be connected to the service port, and high side pressures to be checked by opening the port. The adapter connects, first to the gage hose and then to the high side pressure port, by threading the adapter to the port.
Tool J-38704 is an octagon socket which is used to unthread the A/C high side pressure port from the high side A/C line and then used to thread the new port back onto the high side pressure line.
Service parts are as follows:
Part Part Number ---- ----------- Valve Core Housing and 0-ring 52456273 0-ring 52450548
Parts are currently available from GMSPO.
NEVER REMOVE THE GAGE LINE FROM ITS ADAPTER WHEN THE LINE IS CONNECTED TO THE A/C SYSTEM. ALWAYS REMOVE THE LINE ADAPTER FROM THE SERVICE PORT TO DISCONNECT A LINE. DO NOT REMOVE THE CHARGING HOSE AT THE GAGE SET WHILE ATTACHED TO THE SERVICE HIGH SIDE PORT. THIS WILL RESULT IN COMPLETE DISCHARGING OF THE SYSTEM DUE TO THE DEPRESSED VALVE AND MAY CAUSE PERSONAL INJURY DUE TO ESCAPING REFRIGERANT.
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.