1, the thermostat is always on, which makes the antifreeze circulate too early and the outside temperature is very low. Especially when the car is driving, the cold air will soon cool the antifreeze, the engine water temperature will not come up, and the warm air will not be hot.
2. The water pump impeller is damaged or lost, so that the flow through the warm air water tank is not enough, and the heat does not come up;
3. There is air resistance in the engine cooling system, which leads to poor circulation of the cooling system, resulting in high water temperature and not hot warm air. If there is air in the cooling system all the time, it is likely that the cylinder pad is damaged and air leaks into the cooling system. If the inlet pipe of the heater tank is very hot and the outlet pipe is very cold, this situation should be that the heater tank is blocked and should be replaced.
The car heater uses a blower to blow the heat from the heater tank into the cab. If the air volume is insufficient or the distribution of cold and hot air is not good, the heat of the warm air tank will not be radiated, and the temperature of the warm air will not come up. First of all, check whether the air conditioning filter element is dirty or blocked, and replace it in time if necessary; Then check the operation of each gear of the blower, and each gear must reach sufficient speed. If the knob or button is set to the warm air position, the air volume is large enough, the wind direction is normal, and cold air is blown out, you should check whether the control flap cable of cold and hot air in the warm air box falls off, whether the warm air impeller is damaged, whether the flap falls off or whether the servo motor is damaged, and so on. After troubleshooting, the warm air will be fine. There is something wrong with the car, find the car master. 4S shop professional technician, 10 minutes to solve.