A Water Pump is an important part of the engine cooling system. It moves the coolant in the engine cylinder block and cylinder head and then out into the radiator. This helps to remove the excessive heat from the engine, and the hot coolant passes through the radiator where it cools down and then returns back to the engine. The water pump consists of the housing with a shaft rotating on the bearing pressed inside. At the outer side there is a pulley mounted on the shaft. At the inner side there is a mechanical seal to keep the coolant from leaking out and the impeller that acts like a centrifugal pump. Origin China