TEMP GAUGE NEEDLE FLUCTUATION DIAGNOSIS PROCEDURE

1984 FIERO VEHICLES

Some temperature gage needle fluctuation is normal during warm up. If the gage continues to fluctuate between 180 DEG F and 220 DEG F after the engine is completely warm (15 minutes of driving), the following items should be checked.

1. Verify that the coolant level is correct.

2. Check cooling fan operation.

3. Verify gage operation using CCC-EFI scan tool. If the condition persists after verifying the above, the heater core may be partially plugged. Drain the cooling system, remove the heater hoses at the heater connections, and back flush the core.

IMPORTANT: When refilling the cooling system on the Fiero, it should be com- pletely filled and the reservoir filled to 1/2" from top. The engine should be warmed until engine cooling fan comes on (heater in Off mode), allowed to cool down and refilled as necessary. Keep the coolant level in the overflow reservoir well above the cold level as the system may continue to take in coolant for one or two more heating cycles.

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.