A thermostat is a device that regulates the temperature in the engine of a construction machine. It protects the engine from overheating by controlling the flow of coolant. The thermostat is mounted in the cooling system of the engine and allows it to maintain the optimum operating temperature. When the temperature reaches a predetermined value, the thermostat opens a valve to allow coolant to flow through the radiator. If, on the other hand, the temperature is too low, the thermostat closes the valve, restricting the flow of coolant and increasing the engine temperature. The thermostat is an important component that ensures reliable engine operation and protects the engine from damage.