Vehicle Information 2014-22 Ram 2500 Truck V8 6.4L Thermostat with Housing Assembly 2014-22 Ram 3500 Truck V8 6.4L Thermostat with Housing Assembly 2014-22 Ram 4500 Truck V8 6.4L Thermostat with Housing Assembly 2014-22 Ram 5500 Truck V8 6.4L Thermostat with Housing Assembly What Does a Thermostat Do? The thermostat is a small valve that regulates the temperature in the engine by controlling coolant flow. If the engine is cold, the valve stays closed to let it warm up. However, as the engine warms up, the thermostat slowly opens, enabling coolant to flow through the radiator. This process enables the engine to remain at a safe operating temperature. .
