In the cylinder block of automobile engine, there are a plurality of water channels for cooling water circulation, which are connected with the radiator (commonly known as water tank) placed in the front of the car through water pipes to form a large water circulation system, and the upper water outlet of the engine is equipped with a water pump, which is driven by a fan belt to pump out the hot water in the engine block waterway and pump the cold water in. There is also a thermostat next to the water pump, when the car is just started (cold car), it is not opened, so that the cooling water does not pass through the water tank, only circulates in the engine (commonly known as small circulation), when the temperature of the engine reaches more than 95 degrees, it is opened, the hot water in the engine is pumped into the water tank, and the cold wind blows through the water tank when the car moves forward, taking away the heat. The engine drives the pump bearing and impeller to rotate through the pulley, and the coolant in the pump is driven by the impeller to rotate together, and is thrown to the edge of the pump housing under the action of centrifugal force, and at the same time generates a certain pressure, and then flows out of the outlet or water pipe. The pressure in the center of the impeller decreases due to the coolant being 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, so as to realize the reciprocating circulation of coolant. The bearings that support the shaft of the water pump are lubricated with grease, so it is necessary to prevent the leakage of coolant into the grease and the emulsification of the grease, as well as the leakage of grease. The sealing measures to prevent leakage of water pumps include water seals and gaskets. The water-sealed dynamic sealing ring and the shaft are installed between the impeller and the bearing through interference fitting, and the water-sealed static seal seat is tightly pressed on the housing of the water pump, so as to achieve the purpose of sealing the coolant.
The water pump housing is connected to the engine by a gasket and supports 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 coolant leaks through the water seal, it can be discharged through the drain hole to prevent coolant from entering the bearing cavity and destroying the bearing lubrication and causing corrosion of the components. If coolant is still leaking after the engine has been stopped, the water seal has been damaged.