Card friends know that we should always pay attention to the water temperature during driving. Under normal circumstances, the engine water temperature should be between 80 ° C and 90 ° C. if the water temperature is often higher than 95 ° C or the pot is boiling, we should check the fault. So what causes the water temperature to be too high? I consulted a teacher with 20 years of experience in truck maintenance. He told me the reasons for the high water temperature one by one. I summarize as follows:
1. The coolant in the water tank is below the minimum mark, which means that the daily maintenance is not in place and the lack of coolant is not noticed. Add coolant to the specified scale of seven reasons.
2. The belt of the cooling fan installed on the water tank is not tight enough and slips, resulting in insufficient rotation speed of the fan and water pump. Insufficient rotation speed of the fan leads to too low cold air flow of the water tank, and insufficient rotation speed of the water pump leads to too slow circulation speed of the coolant. Kayou, who is equipped with thermal insulation curtain in front of the water tank, didn’t notice to open the thermal insulation curtain for ventilation and cooling when the water temperature rises. This situation is mostly kayou who often runs to the north in winter of seven reasons.
3. Kayou, who is equipped with thermal insulation curtain in front of the water tank, didn’t notice to open the thermal insulation curtain for ventilation and cooling when the water temperature rises. This situation is mostly kayou who often runs to the north in winter of seven reasons.
4. The blockage of the water pipe in the water tank reduces the section of the water pipe and the water circulation efficiency. Because the blockage of the cooling water pipe in the water tank reduces the section of the water pipe, the amount of water entering the upper water pipe of the water tank in the engine is much more than that entering the engine by the lower water pipe. As a result, the cooled water is accumulated in the upper water pipe of the water tank, increasing the pressure of the upper water pipe and causing the water tank to drain, The reduction of water volume after water discharge causes the engine to overheat.
5. After the thermostat fails, the failure or function attenuation of the thermostat after long-term use will reduce the opening of the valve, resulting in slow or even interruption of water circulation, which will lead to excessive engine water temperature of seven reasons.
The test standard for judging whether the thermostat can continue to be used is to heat the thermostat in water and check the temperature at which the valve starts to open and fully open, as well as the lift of the valve from open to fully open. The temperature when the valve starts to open is generally about 80 ° C, the temperature when it is fully opened is generally about 90 ° C, and the working lift of the valve is generally 7 ~ 10mm.
6. The water pump fails. If the truck does not add antifreeze in cold weather, the water in the water pump is easy to freeze, resulting in the inability of the water pump impeller to rotate. When starting the vehicle, the belt forcibly drives the water pump to rotate, which is easy to cause damage to the water pump of seven reasons.
7. The fan clutch is faulty. Most trucks running on the road are equipped with fan clutch regardless of whether they use domestic or imported engines. The fan clutch can adjust the speed of the fan according to the temperature of the engine to keep the engine working under the best working condition. When the fan clutch fails, it is easy to cause the water temperature to be too high and the water tank to boil.