The water tank is short of water, but there is no leakage.

The reason why the water tank is short of water but can't see water leakage is because the engine is running at high temperature, and the water temperature is high, and the pressure of the water tank is also high, so it is easy to leak water, and it is immediately evaporated by high temperature, so it is not easy to be detected. The water tank cover is not sealed, which may cause the coolant to enter the expansion pot without backflow, resulting in water shortage or aging of the thermostat sealing ring, resulting in water leakage.

Reasons for water shortage in water tank:

1. The water tank cover is not tight;

2. The water pipe interface is not tight or the water pipe leaks;

3. Cracks in the cylinder block and damage to the cushion of the cylinder head will lead to inaccuracy and cross flow of water;

4. The oil radiator seal ring is damaged or has sand holes, resulting in cross flow of water;

5. The heater water tank leaks.

Judgment method:

1. Check the exhaust condition of the exhaust pipe. If it is white steam, it means boiling water. There may be cracks in the cylinder block, and the cylinder head gasket may be damaged, resulting in a decrease in sealing performance. When the cylinder breaks, the return air will be put into the water tank.

2. I feel that the dynamic performance of the car is good, and the cylinder head gasket is not tight or damaged, which will lead to insufficient dynamic performance of the car.

3. Start the engine and check whether there is water leakage at each interface with paper towels or other absorbents.

4. Determine whether the oil radiator sealing ring is damaged by checking whether the oil has water drops and emulsifying phenomenon.