Cooling System Basics

• An engine's cooling system starts in its water jacket, which consists of a system of empty chambers placed around the cylinders and in the cylinder heads. The water pump pulls water out of the water jacket and pushes it through the radiator tubes, and thus into the radiator. A thermostat valve closes off the upper radiator hose when the engine's cold, forcing coolant to recirculate through the block until it warms up.