What are the reasons for a car's air conditioner to freeze up?
2 Answers
Car air conditioner freezing can be caused by the following reasons: 1. Compressor failure: Long-term use may reduce the compressor's efficiency, or damage to the compressor's air distribution system can lead to excessively low pressure, causing icing. The freezing usually occurs in the front part of the evaporator. 2. Excessive refrigerant: Some air conditioners may have refrigerant refilled due to relocation or leakage. Improper handling by maintenance personnel can result in too much refrigerant, leading to excessive refrigerant flowing to the rear part of the evaporator and causing freezing. This type of ice often forms at the rear part of the evaporator and around the compressor's return pipe. 3. Dirty evaporator: After prolonged use, dust from the air or microorganisms generated by the evaporator can accumulate on the evaporator, obstructing airflow, reducing heat exchange, and causing the evaporator temperature to drop too low, resulting in freezing. The freezing typically occurs in the rear part of the evaporator.
During my long-distance trip, the air conditioning suddenly stopped cooling, and it turned out to be caused by icing. Frost formation on the evaporator surface is a common issue, possibly due to insufficient refrigerant causing the system to overcool, or a blocked expansion valve leading to improper refrigerant flow rate. If the AC fan runs at a low speed, inadequate airflow can cause the evaporator temperature to drop too low, resulting in ice buildup. Operating the AC in extremely low ambient temperatures, like using it in winter, can also easily trigger this problem. It's recommended to regularly check the refrigerant level and fan condition, and not overlook the maintenance of the AC system. Once icing occurs, cooling efficiency drops, making it hard to lower the cabin temperature, and it may even damage components. I've learned my lesson and now check the filter before every trip to ensure it's clean and unobstructed.
