This ASHIKA thermostat, part number 38-05-599, is designed to regulate the engine's operating temperature. It plays a crucial role in the cooling system by controlling the flow of coolant. When the engine is cold, the thermostat remains closed, preventing coolant from circulating through the radiator. This allows the engine to reach its optimal operating temperature more quickly, improving efficiency and reducing wear. Once the coolant reaches a specific temperature, the thermostat opens, allowing coolant to flow to the radiator for cooling. This continuous regulation prevents the engine from overheating, ensuring reliable performance under various driving conditions.