2. In-situ idle warm air is hot, and the warm air is not hot when the car is driving. In this case, the thermostat needs to be replaced; The thermostat is often turned on or turned on too early, the coolant circulates too early, and the temperature rises slowly when idling. After the car runs, the cold air coming from the head will make the engine temperature not go up, and the warm air will not be hot. The failure of thermostat is characterized by slow engine heating and high fuel consumption.
3. It is not hot when driving at idle speed. Maybe the heating box is blocked. You can touch the inlet pipe and outlet pipe of the heater water tank. If the water is hot and the water is not hot, it means that the heating water tank is blocked. Most vehicles need to remove the instrument panel to replace or clean the heater. In order to avoid disassembling the center console, you can clean the water tank in this way, remove the inlet and outlet pipes of the heating box, soak them in vinegar or acidic liquid for one hour, and then blow them clean with an air gun. It is also possible that the impeller of the water pump is damaged or lost, resulting in insufficient flow in the warm air box and the warm air is not hot, but the possibility is relatively small.
4. The warm air refueling door is hot, but the refueling door is not hot. Check for lack of antifreeze. The level of antifreeze should be in the middle of the scale. When the coolant level is too low, air may be sucked into the heater pipe, and there is air resistance in the engine cooling system. If the cooling system does not circulate, the warm air will not be hot. If there is air in the cooling system all the time, it may be that the engine cylinder pad is damaged, and the coolant needs to be replenished in time.