Cooling System - Engine Overheats
88chevy06GMC NUMBER: 88-T-86
GROUP: 6B - Engine Cooling
DATE: March, 1988
CORPORATE
NUMBER: 866204
SUBJECT: ENGINE OVERHEAT
MODELS: 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 about 235 degrees F and the engine temperature continues to climb to the 250 degree F mark, an audible noise is heard ("Roar" - due to fan clutch engaugement) and then the temperature returns to a normal indication 205-215 degrees F. 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 245 degrees F. On vehicles built prior to the breakpoints listed below, however, the light is activated at 235 degrees F. If this presents a problem in certain customer applications, the
gauge cluster can be updated by contacting your AC repair center and obtaining a cluster that has the new check gauges resistor. Vehicles built after the VIN breakpoints listed below include the 245 degree F check gauges resistor.
Pontiac - JE 522492
Fort Wayne - JZ 528309
Oshawa - J1 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 include the new fan clutch.
Pontiac - JE 523193
Fort Wayne - JZ 533991
Oshawa - J1 550836
Labor Op: J3390 - Labor Time: 0.3 Hr Clutch Assembly Fan
Labor Op: N4192 - Labor Time: 0.4 Hr Replace Instrument Cluster