The radiator thermostat is a small component, about 2 inches in diameter, found between the engine and the radiator. Its job is to regulate the temperature inside the engine in order to keep your vehicle from overheating. It is a very important part of the cooling system in your car, as it controls the  quantity of coolant that flows through the vehicle or truck.

When the engine is shut off, the thermostat does not let any coolant to pass. Even when the engine is on, the thermostat keeps the coolant in proper order. Only when the temperature of the engine reaches more than 200 degrees F does the thermostat open and let the coolant to flow.

The thermostat has a cylinder filled with wax that is seen close to the engine. As the temperature increases, the wax begins to liquefy. When this happens, the wax expands and then  pushes a rod out of the cylinder. The rod opens the valve and lets the coolant to flow. When the coolant decreases the temperature in the engine, the rod returns to its normal position and the wax begins to cool. This is a simple yet effective way to regulate the engine’s temperature.