Automobile pump structure is relatively simple, is composed of impeller, shell and water seal, impeller is the core parts of the pump, it is generally made of cast iron or plastic, impeller usually has 6 ~ 8 radial straight blade or bent blade. The main damage form of water pump is the damage of the blade and water seal leakage, which is the main damage factor of the blade pump.

In simple terms, there are mainly the following factors that lead to the damage of pump blades:

1. The coolant injected in the cooling system is unqualified, or the coolant is not replaced for a long time. Now the engine is generally used antifreeze as working medium of the cooling system, antifreeze can not only prevent frostbite, also have boiling, rust and corrosion prevention effect, containing corrosion inhibitor, defoaming agent, colorant, fungicide, buffering agent and other additives, can effectively prevent the engine corrosion of the metal substrate and swelling of pipes. If the antifreeze is not corrosive, or the antifreeze is used for too long, the antifreeze additives in the antifreeze are exhausted, and the antifreeze will corrode the pump impeller until the impeller is completely corroded. Now many cars require two years or 40 thousand kilometers to replace antifreeze, mainly for this reason.

2. The cooling system does not use antifreeze but ordinary water instead, which will also accelerate the damage of the pump. As we know, water directly contact with metal, will lead to metal corrosion, if it is not purified tap water or river water, rust phenomenon will be more serious, and lead to the corrosion of the pump blade, damage. In addition, the use of water instead of antifreeze will also produce scale, deposit in the water tank and the engine channel, resulting in poor heat dissipation and even high temperature of the engine.

3, there is air into the cooling system, cavitation corrosion phenomenon corrosion pump blade. Can be seen from the working principle of water pump, the pump when the pump work on the blade is a pressure change, if the cooling fluid contains air bubbles, the bubbles will experience a process of compression, expansion, if it is broken, and in the process of expansion of the broken moment will produce a larger impact, effects on the blade, Over time, the surface of the blade will produce a large number of pitting, which is the phenomenon of cavitation.

Cavitation for a long time will lead to the damage of the pump blade until it disappears. In the open cooling system used in the past, cavitation phenomenon is more serious, basically the damage of the pump blade is caused by cavitation; Cars now use more closed cooling systems, so the chance of air entering the system is greatly reduced, and there is less cavitation. But if the engine is often short of coolant, air will enter, and further aggravate cavitation. The main device for isolating air in the current car cooling system is the expansion water tank. Generally, as long as there is coolant in it, the air will not enter the system.

These are the main factors that lead to the damage of automobile pump blade. In fact, not only the automobile pump, other mechanical pumps also have the same problem, the damage mechanism of pump blade is very complex, involving very profound knowledge of fluid mechanics, as far as possible to slow down the damage process of pump blade, prolong the service life of the pump is a worldwide problem. For our cars, we need to add qualified antifreeze, do not use tap water and river water, do not let the coolant level is too low, which can effectively avoid damage to the pump blade.