What Causes the Car Air Conditioner Evaporator to Freeze?

[EmersonFitz]

Here is a detailed introduction to the causes of car air conditioner evaporator freezing: 1. Expansion valve: The adjustment range of the expansion valve is too small, resulting in excessively low low-pressure. 2. Refrigerant: Insufficient refrigerant in the system leads to excessively low evaporation pressure. 3. Internal circulation: The internal circulation filter is clogged. 4. Temperature control failure: The temperature control (or temperature sensor) malfunctions, causing the compressor to run continuously. 5. Variable displacement compressor: The energy control valve (pressure regulating valve) of the variable displacement compressor fails, keeping the compressor operating at full capacity, resulting in excessively low low-pressure and evaporator freezing.

[DeGavin]

That day I found the air conditioning wasn't cooling when I was driving, so I took it to the repair shop and saw the evaporator was covered with a thick layer of ice! The mechanic said this situation often occurs because there's too much refrigerant or the expansion valve is stuck, causing the evaporator temperature to drop below freezing. Another possibility is that the cabin air filter is clogged, resulting in insufficient airflow to carry away the cold air, causing moisture to condense into ice. I remember replacing the expansion valve solved the problem at that time. If the icing persists, it will affect cooling performance and may even freeze and damage components inside the evaporator, so it needs to be addressed promptly.

[MacAdrian]

My old car used to blow cold air from the vents but with very low airflow. After disassembly, it was found that the evaporator was frozen. The mechanic analyzed that the temperature control sensor was faulty, causing the compressor to run continuously without stopping, which resulted in the evaporator becoming too cold and freezing. Additionally, insufficient refrigerant can also lead to abnormal pressure, causing the evaporator temperature to drop too low. It is recommended to regularly clean the air conditioning system and replace the filter to avoid dust blockage that can reduce airflow. Addressing the freezing issue promptly can also save some fuel, as the compressor consumes quite a bit of fuel when it runs continuously.

[GrahamMarie]

Last time, the car wash shop owner mentioned that my car's air conditioning was making unusual noises, and upon inspection, it turned out the evaporator was frozen. He said common causes include: insufficient purity of the refrigerant mixed with moisture, impurities in the system clogging the expansion valve, or a faulty temperature switch causing the compressor to run continuously. The usual solutions are to vacuum and recharge the refrigerant, and clean the air conditioning lines. Long-term freezing can lead to poor refrigerant circulation, putting excessive load on the compressor and making it prone to damage. It's advisable not to run the air conditioning at the lowest temperature for extended periods during normal use.