What is the purpose of an automotive thermostat?

[MaverickRose]

The purpose of an automotive thermostat is to function as a valve controlling the flow path of engine coolant. It automatically regulates the amount of water entering the radiator based on the coolant temperature, thereby playing a role in energy conservation. The thermostat must maintain good working condition; otherwise, it will seriously affect the normal operation of the engine. If the thermostat opens too late or fails to open, it can cause the engine to overheat. Conversely, if it opens too early, it prolongs the engine warm-up time, resulting in the engine temperature being too low. Methods for detecting thermostat faults in automobiles include: 1. When the coolant temperature exceeds 110 degrees, stop the car, turn off the engine, open the engine hood, and feel the upper and lower radiator hoses for a significant temperature difference; 2. If the engine does not reach normal operating temperature for an extended period, stop the car and allow the engine temperature to drop to ambient temperature. Then, restart the engine and observe the dashboard. When the temperature rises to around 70 degrees, stop the car, turn off the engine, open the engine hood, and feel the upper and lower radiator hoses for any temperature difference.