W5 COOLANT TEMP. GAGE READS HIGH OPERATION INFORMATION

SUBJECT: "W5" COOLANT TEMPERATURE GAUGE READS HIGH

VEHICLES AFFECTED: 1988-92 "W5" TRUCKS

Some owners of W5 series Forward/Tiltmaster vehicles may comment that their coolant temperature gauge reads high. The W5 temperature gauge reads high when compared to other Forward/Tiltmaster Truck models when the engine has reached the normal operating temperature (Figure 1).

This condition occurs due to the matching of the Coolant Temperature Sensor (CTS) and the gauge display unit. The W5 uses the same coolant temperature gauge as the W4 (4 cylinder engine) and the same CTS as the W7 series vehicle (6 cylinder engine).

Important: Do not compare the gauge reading of the W5 with other Isuzu Truck models.

The white section of the temperature gauge is the normal operating range. If the pointer moves beyond the white line and into the red, an overheat condition may exist. If there is any question, the coolant temperature can be easily tested using your TECH I Tool. The normal operating temperature for all W5 vehicles is between 85 degrees C (185 degrees F) and 91 degrees C (195 degrees F).

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.