ENGINE OVERHEAT WITH SNOWPLOW IN UP POSITION

VEHICLES AFFECTED: 1988 C/K TRUCKS WITH 5.7L (VIN CODE K) ENGINE AND UPFITTED WITH SNOWPLOWS

Some 1988 C/K trucks with 5.7L engines and upfitted with snowplows may experience an engine overheat condition while driving with the plow in the "up" position. This condition may be indicated by one or both of the following indications.

Trucks Without Gauges

Engine temperature light comes on, then an audible noise is heard ("Roar" - due to fan clutch engagement) and then the temperature light goes out.

Trucks With Gauges

Check gauge light comes on at about 113 degrees C and the engine temperature continues to climb to the 120 degree C mark, an audible noise is heard ("Roar" - due to fan clutch engagement) and then the temperature returns to a normal indication 95 - 100 degrees C.

If these conditions are encountered on trucks with or without gauges, they can be repaired by replacing the fan clutch with P/N 15550738.

NOTICE: On vehicles with gauges, the check gauges light was designed to activate at 118 degrees C. On vehicles built prior to the breakpoints listed below, however, the light is activated at 113 degrees C. If this presents a problem in certain customer applications, the gauge cluster can be updated by contacting the AC repair center (Custone) and obtaining a cluster that has the new check gauges resistor.

Vehicles built after the VIN breakpoints listed below include the 118 degree C check gauges resistor.

Pontiac - Chevrolet - JE 164595 GMC - JE 522492

Fort Wayne - Chevrolet - JZ 200778 GMC - JZ 528309

Oshawa - Chevrolet - Jl 123424 GMC - Jl 550836

Remove the cluster using procedures in Section 8C - Instrument Panel and Gauges of the 1988 C/K Service Manual.

Install the new cluster.

Vehicles built after the VIN breakpoints listed below ilnclude the new fan clutch.

Pontiac - Chevrolet - JE 166664 GMC - JE 523193

Ft Wayne - Chevrolet - JZ 211190 GMC - JZ 533991

Oshawa - Chevrolet - Jl 230424 GMC - Jl 550836

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.