1. The thermostat is always open or the thermostat is opened too early, causing the cooling system to undergo a large cycle prematurely, while the outside temperature is very low, especially when the car is running, the cold wind quickly kills the antifreeze. With liquid cooling, the engine water temperature will not rise, and the heater air will not heat up.
2. The water pump impeller is damaged or lost, causing insufficient flow through the small warm air water tank and preventing heat from coming up.
3. There is air blockage in the engine cooling system. The air blockage leads to poor circulation of the cooling system, causing high water temperature and low heating of the warm air. If there is always air in the cooling system, it is likely that the cylinder gasket is damaged and air is flowing into the cooling system; if the water inlet pipe of the small heater water tank is very hot and the water outlet pipe is cold, this situation should be that the small heater water tank is blocked. , the small heater water tank should be replaced.