What Causes the Low-Pressure Pipe of a Car's Air Conditioning to Become Hot?

[JasperFitz]

The reasons for the low-pressure pipe of a car's air conditioning becoming hot to the touch include compressor or expansion valve failure, evaporator blockage, insufficient refrigerant flow, or excessively high pipeline pressure, as well as excessive accumulation of dirt in the condenser's copper pipes. More details are as follows: 1. Compressor or expansion valve failure: This can cause the low-pressure pipe of the car's air conditioning to become hot. The air conditioning compressor plays a role in compressing and driving the refrigerant in the air conditioning refrigerant circuit. The compressor extracts the refrigerant from the low-pressure area, compresses it, and sends it to the high-pressure area for cooling and condensation. The heat is then dissipated into the air through the radiator, and the refrigerant changes from a gaseous to a liquid state, increasing in pressure. 2. Expansion valve blockage: If the air conditioning is not working, check whether the refrigerant is sufficient. If it is insufficient, the system needs to be vacuumed before adding refrigerant, and then use a pressure gauge to check whether the pressure in the high and low-pressure pipelines is normal.