Causes of water overflow in the cooling water tank

causes of water overflow failure of engine cooling water tank:

Mitsubishi 8dc series water-cooled engines often have water overflow failure of engine cooling water tank during use. Knowing the main causes will facilitate our symptomatic maintenance and timely troubleshooting

1. The cylinder gasket is damaged due to aging:

when the cylinder gasket has small scars near the combustion chamber, the overflow is not as serious and obvious as when the cylinder gasket is washed out; At the same time, after the cylinder pad is washed out, not only the water tank will overflow, but also the engine oil will deteriorate due to water inflow; The two are easier to judge; After the cylinder gasket is slightly damaged, only when the cylinder is working can it produce a strong explosive force, so that the high-pressure gas seeps into the water channel, and the negative pressure caused by air intake is not enough to suck water into the cylinder from the water channel, so at this time, only the water tank overflows without obvious oil deterioration

2. The water blocking jacket of the fuel injector is not tightly sealed or has cracks:

there is a water blocking jacket between the fuel injector and the cylinder head on this series of engines. The surrounding of the water blocking jacket is connected with the water channel and sealed with a rubber sealing ring. After long-term use, the cylinder head will produce tiny cracks in the joint of the water jacket and the cylinder head due to aging, or the sealing is poor due to rubber aging, and the burned mixture will penetrate into the water channel through this tiny crack, Thus, the water in the water tank overflows. Automobile maintenance

3. Thermostat failure:

the cooling water on the water-cooled engine can be divided into large circulation and small circulation. At the initial stage of engine startup and when the water temperature is below 90 ℃, the thermostat is closed. Once the temperature exceeds the set temperature, the thermostat opens, so that the water path circulates through two circulating water paths at the same time, that is, the opening degree of the thermostat varies with the temperature, Thus, the flow of water is also different. When the two thermostats are rusted due to long-term use, the large circulating water circuit is completely open; In addition, due to the small cross-sectional area of the small circulating water path, the flow resistance is large, causing most of the water to pass through the large circulating water path (this phenomenon is more obvious after the accelerator is suddenly increased), so that the water overflows from the water tank. This phenomenon is very rare in domestic machines, and domestic machines sometimes remove the thermostat artificially in summer to prevent the machine temperature from being too high, so there will be no water tank overflow. Valve imported pump

4. The cylinder head of the air pump is cracked:

the steel of this series of engine air pump needs 0.8 ⑴ dollars. The cylinder block is water-cooled. If there is a hidden injury or minor crack on the cylinder head, compressed air will enter the water channel from the crack when the air pump works, and then overflow from the water tank; When the accelerator is suddenly increased, this phenomenon is more obvious, and there is an illusion that the water tank is boiling

5. The oil radiator is faulty:

at the oil radiator, the oil pressure is higher than the water pressure. There may be two situations when the oil radiator is faulty: one is that the radiator core has cracks or sand holes; First, the sealing rubber ring at the interface between the radiator core and the oil duct of the cylinder block is not tightly sealed. Thus, the oil enters the water, and too much oil overflows from the water tank after entering the water (this situation is easier to judge, because the organic oil overflows from the water tank with water, and the oil will only become less and will not deteriorate)

6. There is too much dirt in the water tank:

the upper and lower water chambers of the water tank are connected by several water distribution pipes. If you don't pay attention to the use and make more after tax accumulated in the water tank, it is easy to cause the water distribution pipe to be blocked; When the engine is running at high speed, one part of the water flows into the small circulation after passing through the water pump, and the other part enters the water supply chamber of the water tank. However, due to the blockage of the water distribution pipe, the water overflows from the water supply chamber. At this time, when you touch the upper and lower parts of the water tank with your hands, you will find that there is a significant temperature difference. In case of elimination, only disassemble the water tank and dredge the water pipe when the experimental conditions cannot meet the requirements; Or add vinegar to the water tank to make the engine run for 5mi. It is understood that after several cycles, the water tank can be basically cleaned. This method is convenient and low cost