Diagnostic Aids
If an overheating condition is suspected, verify if it is due to an actual boilover. If gauge or light indicates an overheat condition and boilover is not evident, inspect gauge circuit for malfunction.
If vehicle is overheating and gauge or light indicates so but cooling fans are not coming on, check coolant sensor temperature using Tech 1 scan tester. Sensor may have shifted out of calibration and should be replaced. If engine is overheating and cooling fans are on, check cooling system.