What is the principle of a thermostat?

[JonathanFitz]

Thermostat automatically adjusts the amount of water entering the radiator based on the temperature of the coolant, changing the circulation range of the water to regulate the cooling capacity of the radiator, ensuring the engine operates within an appropriate temperature range. Here is relevant information: 1. The thermostat must maintain good technical condition; otherwise, it will severely affect the normal operation of the engine. If the main valve of the thermostat opens too late, it will cause the engine to overheat; if the main valve opens too early, it will prolong the engine's warm-up time, resulting in the engine temperature being too low. 2. The main type of thermostat currently in use is the wax-type thermostat. When the coolant temperature is below the specified value, the paraffin in the thermostat's temperature-sensing body remains in a solid state, and the thermostat valve closes the channel between the engine and the radiator under the action of the spring, causing the coolant to return to the engine via the water pump. When the coolant temperature reaches the specified value, the paraffin begins to melt and gradually turns into a liquid.