what does a thermostat do in a car

A thermostat in a car is responsible for regulating the flow of coolant through the engine to maintain a minimum operating temperature. When the engine is cold, the thermostat remains closed, preventing the coolant from flowing through the engine. As the engine warms up, the thermostat slowly begins to open, allowing the coolant to flow through the radiator to keep the engine at a temperature close to the rated temperature of the thermostat. This helps the engine warm up quickly, reducing engine wear, deposits, and emissions. The thermostat achieves this through a small cylinder filled with wax that expands and contracts based on the temperature, opening and closing the valve as needed.