The warm air pipe is a pipe that brings the heat of the engine into the car through the water in the car water tank, thus keeping the car warm. Usually in and out. If it is not installed correctly, it may make the water flow too smooth and will not have much impact. If it is broken, it will cause the coolant of the car to leak, the engine will not dissipate heat well or can not, and the water temperature will rise, which will do great harm to the car.