CORRECT OPERATION

Your thermostat usually becomes fully open at a temperature about 20° F. greater than the thermostat's rating. It may take about 10-15 minutes for the engine to reach operating temperature. At that time, the upper radiator hose connecting the engine block to the radiator will be hot to the touch. If it is not, the thermostat is faulty and must be replaced.

SYSTEMS
THERMOSTAT
REPLACING YOUR THERMOSTAT
VARIATIONS