THERMOSTAT

A temperature sensitive device used in the cooling system of an engine to control the flow of coolant between the cylinder block and radiator . It is set into the engine block and shuts off the circulation of water until the temperature of the water reaches the point at which the thermostat is set to open. Because automotive internal combustion engines operate more efficiently when their temperature is maintained within narrow limits, the thermostat closes off the flow of coolant from the engine to the radiator until the engine has reached the desired operating temperature. Other thermostats are used in the electrical circuit of the vehicle heating system to control the amount of heat supplied to the passengers, in the manifold heat control system that preheats the air-fuel mixture going to the cylinders , and in the automatic choke .