The engine drives the water pump bearing and impeller to rotate through the belt pulley, and the coolant in the water pump is driven by the impeller to rotate together. Under the action of centrifugal force, it is thrown to the edge of the water pump housing, at the same time, it generates a certain pressure, and then flows out of the water outlet or water pipe. The pressure in the center of the impeller is reduced because the coolant is thrown out, and the coolant in the water tank is sucked into the impeller through the water pipe under the pressure difference between the water pump inlet and the center of the impeller to realize the reciprocating circulation of the coolant.

The bearing supporting the water pump shaft is lubricated with grease, so it is necessary to prevent the coolant from leaking to the grease to cause the grease emulsification, and at the same time prevent the grease from leaking. The sealing measures to prevent leakage of water pump include water seal and gasket. The water seal dynamic seal ring and the shaft are installed between the impeller and the bearing through the interference fit, and the water seal static seal seat is tightly pressed on the shell of the water pump, so as to achieve the purpose of sealing the coolant.

The water pump housing is connected with the engine through a gasket and supports the moving parts such as bearings. There is also a drain hole on the water pump housing, which is located between the water seal and the bearing. Once the coolant leaks through the water seal, it can be discharged from the drain hole to prevent the coolant from entering the bearing cavity, damaging the bearing lubrication and causing corrosion of components. If coolant still leaks after the engine stops, the water seal is damaged.