2. The thermostat is often opened or opened too early, which makes the cooling system carry out a large cycle too early, 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.
3. 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.
4. 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 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.