First, this phenomenon is caused by the failure of vehicle coolant. If this coolant is not replaced for a long time, it will fail. In this case, it will affect the water temperature of the vehicle engine. In this case, it is recommended to replace the coolant with a new one. In general, the replacement cycle of coolant is about two years or 40 thousand kilometers.
Secondly, this phenomenon is caused by the problem of vehicle engine thermostat. This is the need to check the thermostat. If there is a problem, it needs to be replaced in time.
Thirdly, there is no warm air in the car because the heater tank of the car is blocked. In this case, it is necessary to dredge the warm air tank or replace it with a new one.