What Causes the High-Pressure Pipe of a Car's Air Conditioning to Become Hot to the Touch?
2 Answers
High temperature in the high-pressure pipe is a typical symptom of excessive refrigerant in the system. It is recommended to check the pressure on the high-pressure side and appropriately reduce the system pressure. Below are relevant details: Compressor: The compressor acts like a high-pressure pump, pressurizing the refrigerant and sending it to the condenser. The refrigerant is cooled in the condenser to near room temperature and then drastically cooled by the throttling device. Finally, the low-temperature refrigerant absorbs heat in the evaporator to achieve cooling. Components: The operating principle of a car's air conditioning is the same as that of a household air conditioner. The system mainly consists of four major components: the compressor, condenser, throttling device, and evaporator.
It's actually quite common for the car's AC high-pressure line to feel hot to the touch. When I was younger driving older model cars, I encountered this several times. Normally, the pipe will get warm because the AC compresses refrigerant during operation, and heat is a byproduct of compression, so slight warmth is a normal physical phenomenon. However, if it becomes extremely hot to the point where you can't touch it, there might be an issue. Common causes include overcharging the AC with refrigerant leading to excessive pressure, a dirty condenser surface blocking heat dissipation, or a cooling fan that's stopped working. I remember one summer during a long drive when the fan seized up, causing the high-pressure line temperature to skyrocket—almost leading to an accident. I recommend regularly keeping the engine bay clean, checking the fan's operation periodically, and stopping to cool down and get repairs if overheating is noticed. Don’t take it lightly to avoid injury. Safe driving comes first.
