What Causes Car AC to Frost Up and Stop Cooling?
2 Answers
Car AC frosting up and failing to cool is caused by insufficient refrigerant; excessively dirty condenser; or clogged air filter. The air filter serves three main functions: Providing fresh air: Prevents windshield fogging for clear driver visibility and safer driving; Supplies fresh air to the cabin, protecting occupants from harmful gases and ensuring driving safety; Effectively eliminates bacteria and odors. Ensuring hygiene: Maintains clean cabin air by preventing bacterial growth and effectively filtering out solid particles like dust, pollen, and grinding residues; Blocks pollen to prevent allergic reactions that could compromise driving safety. Adsorbing harmful substances: Removes moisture, soot, ozone, and odors from the air with strong and long-lasting moisture absorption capabilities.
Speaking of the issue of car air conditioning frosting and not cooling, I often encounter this situation during long-distance driving. The root cause is usually insufficient refrigerant in the air conditioning system or a faulty expansion valve, which leads to the evaporator temperature dropping too low and freezing. Think about it: in summer, if the thermostat fails, the compressor keeps running non-stop, and excessive cooling can cause frosting. If the blower fan isn't working or its speed is insufficient, poor air circulation prevents the ice from melting, naturally resulting in no cooling effect. Additionally, if the evaporator's drain hole is clogged, water can't drain out, accelerating ice formation. My experience suggests first checking if the air filter is dirty, as a clogged filter can worsen the problem. Then, manually check the airflow volume, and have someone test the refrigerant pressure and expansion valve condition. Early maintenance can save you from costly repairs later. Otherwise, driving without air conditioning is not only uncomfortably hot but also dangerous, affecting safe driving.
