Engine Coolant Thermostat: Operation
WARNING: This page is about a different car, the 2003 Dodge Intrepid, 2003 Chrysler Intrepid, 2003 Chrysler Concorde, and 2003 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
The engine cooling thermostat is a wax pellet driven, reverse poppet type. The thermostat is located in the inlet side of the engine to provide fast warm up and to optimize a consistent temperature in the engine. The thermostat is designed to prevent leakage through it and to guarantee a minimum engine operating temperature of 82°C (180°F). They also automatically reach wide open at a temperature of approximately 95°C (203°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.