Due to the high specific heat capacity of water and has good heat transfer between the components and cooling medium performance, so most modern car enginewater cooled. Using water as a cooling medium engine known as a water cooled engine. Coolant is water, conveyed by pumps, flow through the engine and the water radiator. When in a car, used wind flow or through fan forced cooling flow radiator water. Coolant (water) temperature by the thermostat valve adjustment.