A/C COMPRESSOR BELT BREAKAGE INCORRECT BELT INSTALLED

Model and Year: 1985-86 M VANS EQUIPPED WITH THE 4.3L V6 ENGINE

TO: ALL CHEVROLET DEALERS

Some 1985-86 M Vans equipped with the 4.3L V6 engine and air conditioning (A/C) may experience low mileage A/C compressor belt wear. This condition may be caused by an incorrect belt being installed during production of the vehicle. The incorrect A/C belt (3/8" x 55") has a center cordline (CCL) too low in the belt cross section which can cause overloading of the belt. Starting with 1986 Chevrolet M Vans with VIN GB 165458, a new A/C belt (3/8" x 54.5" "High Ride") which has a higher CCL has been released for production and service use. If this condition is encountered, replace the A/C Compressor belt with P/N 469594. Tighten belt to 645 N (145 lb.) using belt tension gage J-23600-B or BT 33-95-ACBN. Refer to the belt replacement procedures in the Light Duty Service Manual, Section 6B, Engine Cooling.

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.