First, the heating box is blocked. The structure of the warm air water tank is actually a miniature version of the radiator of the engine water tank, and there are many small cooling pipes in it, which are as easy to block as the radiator of the water tank. After the inside of the warm air water tank is blocked, the coolant flows slowly, the flow rate becomes smaller, and the heat is insufficient, so the air conditioner warm air is naturally not hot.
Secondly, the cooling system lacks coolant. Coolant, commonly known as antifreeze, comes from this, and its principle is different from that of household air conditioning heating. Automobile warm air circulation is to connect a pipeline in parallel in the small circulation pipeline of engine coolant, which is connected with a warm air water tank, and the blower blows the warm air water tank to generate warm air, which is how the air conditioning warm air comes from. The lack of coolant in the cooling system is the most common and easily solved fault phenomenon that causes the warm air not to be hot.
Finally, the thermostat is out of order. The common fault of the thermostat is that it can't be opened, but the reason why the warm air is not hot due to the thermostat fault is that the thermostat can't be closed, commonly known as the thermostat is always open. After the thermostat is normally open, the coolant begins to circulate from the idle speed of the engine. If the water temperature is low for a long time in winter in the north, the air conditioning warm air is naturally not hot. It is obvious from the thermometer that the pointer is obviously lower than the normal scale. In addition, low water temperature for a long time will lead to high fuel consumption and increased wear, so it is necessary to carry out maintenance and inspection immediately when the water temperature is low for a long time.