MOAN NOISE WITH AIR CONDITIONING ON

MODELS: 1985-1988 LIGHT AND MEDIUM DUTY VEHICLES WITH THE R-4 A/CCOMPRESSOR AND WITHOUT SERPENTINE BELT DRIVE

An A/C moan on a light or medium duty vehicle equipped with one of the engines listed below can be addressed by replacing the A/C compressor pulley.

YEAR MODELS ENGINES ---- ------ ------- 1985 C/K 5.0L 5.7L M 4.3L S/T 2.8L G 4.3L 5.0L 5.7L MED. DUTY 4.8L

1986 C/K 4.3L 5.0L 5.7L M 4.3L S/T 2.8L G 4.3L 5.0L 5.7L MED. DUTY 4.8L

1987 R/V 4.3L 5.0L 5.7L G 5.7L (LT9 ONLY)

1988 R/V 5.0L 5.7L G 5.7L (LT9 ONLY)

The new pulley, P/N 6552402, is a single "V" groove high inertia pulley, which is heavier than the original "V" groove pulley. Refer to Section 1B of the appropriate service or unit repair manual for removal and installation procedures.

Labor Op: D4280

See Labor Time Guides for applicable times.

Notice: Prior to ordering the new pulley, visual verification should be made that the vehicle is equipped with the R-4 compressor and is not serpentine belt driven.

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.