Possible problems in the cooling system are:
First, the thermostat is always open or opened too early, which makes the cooling system have a big cycle prematurely, and the outside temperature is very low. Especially when the car is driving, cold air quickly cools the antifreeze, the engine water temperature does not come up, and the warm air does not heat up.
Second, the water pump impeller is damaged or lost, so that the flow through the warm air small water tank is insufficient and the heat cannot come up.
Third, the engine cooling system has air resistance, which leads to poor circulation of the cooling system, resulting in high water temperature and no warm air. If there is gas in the cooling system all the time, it is likely that the cylinder pad is damaged and the gas leaks into the cooling system; If the inlet pipe of the small heating tank is very hot and the outlet pipe is very cold, this situation should be that the small heating tank is blocked and should be replaced.
The warm air of the car is blown into the cab by the blower. 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. At this time, first check whether the filter element is dirty and blocked, clean it, 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 is set to the warm air position, the air volume is large enough and the wind direction is normal, and the cold air is blown out, check whether the cable of the hot and cold air control flap in the warm air box falls off, whether the warm air impeller is damaged, whether the flap falls off, etc. After troubleshooting, the warm air will get hot.