Thermostat: Description and Operation

PURPOSE
The engine cooling thermostats are wax pellet driven, reverse poppet choke type. They are designed to provide the fastest warm up possible by preventing leakage through them and to guarantee a minimum engine operating temperature of 90°C (195°F). They also automatically reach wide open at a temperature of approximately 102°C (215°F) so they do not restrict flow to the radiator as temperature of the coolant rises in hot weather to around 104°C (220°F). Above 102°C (215°F) the coolant temperature is controlled by the radiator, fan, and ambient temperature, not the thermostat.

LOCATION
The engine thermostat is located in a water box, formed in the front of the lower intake manifold. This thermostat has an air bleed located in the thermostat flange.