The Passat gets warm after being turned on for a while

Whether it is winter or hot weather, we often use air conditioners, especially in cold winter. Turning on the heater can adjust the interior of the car to a comfortable temperature. Today let’s talk about the problem of lack of heating in cars. What's the problem? First, let’s briefly talk about the principle of air conditioning and heating. Different from air conditioning refrigeration, warm air is completed through the heat of engine antifreeze. That is, the antifreeze circulating in the engine enters the small water tank in the air conditioner evaporation box through pipelines, flow valves, and circulation valves. After the blower is running, the air flows to the small water tank. Because of the heat, the air becomes hotter so it can be blown out through the air vents of the air conditioner. In this process, many electronic and mechanical components are used, such as air conditioning outlet sensors, evaporation box temperature sensors, flow valves, circulation valves, water temperature sensors, regulating devices, etc. , and may also participate in work. If there is no warm air in the car, we first determine whether the air outlet of the following air conditioners is blowing out and whether it is cool or not. If there is no wind, the blower may be damaged, the air conditioning filter may be dirty and clogged, the damper motor may be damaged, or the damper may be stuck. Another way is that there is wind from the air outlet, but it is not hot air. If the warm air is not hot, there is no need to make a complicated judgment: first check whether the engine water temperature is normal. If it has been in a low temperature state and has not reached the operating temperature, the warm air will definitely not be hot. At this time, you can focus on whether the thermostat is always in a large cycle state, or whether the signal of the water temperature sensor is true, etc. Simply repair or replace the original faulty issue. Second, we should focus on whether there is a large temperature difference between the inlet and outlet pipes in front of the heating water tank. If this happens, the heating water tank must be clogged and needs to be disassembled, removed or replaced. Again, it depends on whether the flow rate and temperature of the antifreeze entering the heater water tank meet the requirements. The temperature is measured by an infrared thermometer, and the flow rate is stored through the diagnostic data and fault problems of the tester to make a comprehensive judgment. Often the water pump is lost and damaged, and the heater flow valve and antifreeze circulation valve are damaged. Fourth, it depends on whether the antifreeze system has air resistance. It is often encountered that there is no exhaust after replacing the antifreeze. The special cylinder gasket is damaged. This can be further determined by using standard antifreeze venting methods.