ACCESSORY DRIVE BELT COMES OFF NO A/C (NEW COMPRESSOR DESIGN)

Subject: ACCESSORY DRIVE BELT COMES OFF OR NO AIR CONDITIONING

Model and Yeor: 1993 C/K TRUCK

CONDITION:

---------- Some owners of early built 1993 C/K trucks with 4.3L (LB4), 5.OL (LO3), or 5.7L (LO5) engines may comment on their accessory drive belt coming off when the air conditioner (A/C) is on, or of no air conditioning.

CAUSE:

------ If the cause of the no air conditioning comment is determined to be a damaged electrical connector on the compressor and there is no obvious reason for the belt coming off, the cause could be "slugging" of the A/C compressor. "Slugging" is caused by liquid refrigerant passing through the compressor.

CORRECTION:

---------- In November 1992, a change was made in the compressor to reduce the effect of "slugging." Trucks built before the VIN breakpoints listed below or having a compressor built before November 16,1992 may need a new compressor. The new compressor part number is 12355387. Be sure the date code on the new compressor indicates manufacture after November 16, 1992 (see figure 1 for code location).

Parts are currently available through GMSPO.

Plant VIN Breakpoint ----- -------------- Fort Wayne (VIN Code Z) PZ152679 Pontiac East (VIN Code E) PE150167 Oshawa (VIN Code 1) P1163241 Janesville (VIN Code J)

IMPORTANT: Before installing an A/C service compressor, the oil in the compressor should be drained. All service compressors are shipped with 6 oz. of oil. If the oil is not drained, the cooling capacity of the A/C system will be severely restricted. Refer to the appropriate service manual (Section 1B) for the correct amount of oil to be added when charging the system.

WARRANTY INFORMATION: Use applicable labor operation and time.

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.