GM Service Manual Online
For 1990-2009 cars only

ENGINE OVERHEATS -POSSIBLE INCORRECT THERMOSTAT INSTALLED

VEHICLES AFFECTED: 1986-87 6.0/7.0/7.4L ENGINES (ENGINE CODES 7.4L LIGHT DUTY N AND W, 6.0/7.0L MED. DUTY B AND E

There have been reported cases of 6.0/7.0/7.4L engine overheats that were caused by having the wrong style thermostat installed. When investigating for cause of engine overheat, check for proper style of thermostat (See Illustration).


Object Number: 74825  Size: FS

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.