Driven by a pulley via the timing or fan belt your engine water pump is required to circulate coolant around the engine in order to transport heat generated by the combustion cycle from the cylinder heat to the radiator.Four key areas of focus make up the manufacturer of GMBs range of water pumps. These are the bearing which represents the life the impellers which determines the pumping capability the mechanical seals which represent the efficiency and the housing that governs the ruggedness of the water pump.