What Causes BMW Air Conditioning to Freeze?

[McSawyer]

Reasons for car air conditioning freezing include pressure issues, filter blockage, and temperature control problems. Causes of freezing: The expansion valve's adjustment is too small, resulting in excessively low low-pressure; insufficient refrigerant in the system leads to low evaporation pressure; the internal circulation filter is blocked; the temperature control (or temperature sensor) fails, causing the compressor to run continuously; the energy control valve (pressure regulating valve) of the variable displacement compressor fails, keeping the compressor operating at full capacity, which results in excessively low low-pressure and evaporator frosting. Solutions for air conditioning freezing: First, clean the air conditioning system thoroughly before use, and check the sealing condition. Poor sealing cannot be compensated by adding refrigerant, so pay attention to regular maintenance. Also, the air conditioning needs periodic rest, so avoid using it for too long. After using the air conditioning for a while, turn it off and open the window for ventilation.

[Mallory]

After all these years of repairing cars, I've encountered quite a few cases of BMW air conditioning icing up. The most common issue is incorrect refrigerant charge - too much or too little can cause the evaporator temperature to drop too low and freeze. A faulty expansion valve is also troublesome; it controls refrigerant flow, and if it gets stuck or malfunctions, refrigerant keeps pouring into the evaporator, leading to ice formation. The thermostat is another critical component - if it fails, temperature sensing goes haywire, and the AC keeps cooling non-stop. Also, if the blower motor runs at insufficient speed or the air filter gets too dirty, reduced airflow makes the evaporator more prone to freezing. Pipe blockages can cause similar problems too. To avoid these headaches, it's best to get annual AC checkups, replace filters regularly, and ensure proper refrigerant system pressure - this way you can use your AC with peace of mind.

[AnnaDella]

Last time my car's AC froze up, leaving me sweltering in the summer heat. The cooling effect suddenly deteriorated, and the inspection revealed that overcharged refrigerant caused the evaporator to freeze. The mechanic said an expansion valve failure could also cause this, allowing refrigerant to flow uncontrollably to the evaporator. The thermostat is equally crucial—if it fails to detect temperature changes, the AC becomes ineffective. That's when I realized I often forgot to replace the cabin air filter, which restricted airflow and made the evaporator more prone to freezing. Clogged ducts and insufficient blower fan speed are other potential causes. That repair cost me over 800 yuan to replace the expansion valve—painful but acceptable. Now every spring, I proactively check airflow and system pressure. Developing the habit of preventive maintenance really saves a lot of trouble.

[VonEmily]

BMW air conditioning icing is often caused by issues in the refrigeration system. Excessive or insufficient refrigerant can lower the evaporator temperature too much, leading to frost formation. Additionally, abnormal expansion valves can disrupt refrigerant flow, causing continuous cooling. A malfunctioning temperature control sensor may keep the air conditioning running endlessly, worsening icing. Airflow problems should also be noted—insufficient airflow makes the evaporator particularly prone to freezing, often due to clogged filters. It's recommended not to set the air conditioning temperature too low or use recirculation mode for extended periods. Timely replacement of air filters and regular pressure checks are key maintenance measures.