Diagnostic Aids

Whenever owner complains of an overheating problem, determine if complaint was due to an actual boilover, or TEMP light or gauge indicated overheating. Whenever gauge or light indicates overheating, but no boilover is detected, gauge or light circuit should be checked. Gauge accuracy can also be checked by comparing engine coolant temperature sensor reading with gauge reading.

If engine is actually overheating, and gauge indicates overheating, but cooling fan is not coming on, ECT sensor has probably shifted out of calibration and should be replaced. Whenever engine is overheating and cooling fan is on, cooling system should be checked.