What Causes Car AC to Stop Cooling After Half an Hour of Operation?
4 Answers
Here are the specific reasons why a car's air conditioning stops cooling after half an hour of operation: 1. Lack of refrigerant: The AC is low on refrigerant. Unless the vehicle has been involved in a severe rear-end collision or had its AC piping and other components disassembled, affecting its sealing, the refrigerant should not deplete. 2. Dirty condenser: The radiator and condenser are crucial cooling components of the vehicle. If they are too dirty, it can lead to poor heat dissipation, which not only causes engine overheating but also directly affects the cooling efficiency of the AC. Therefore, if the AC performance is unsatisfactory during hot weather, consider whether the vehicle's cooling system needs cleaning. 3. Aging or loose compressor belt: Typically, the 4S shop will remind you to replace the compressor belt during maintenance. Failing to replace it on time can result in slipping during use, leading to belt breakage, unusual noises, and loss of power assistance.
I've been repairing cars for over ten years and have encountered many cases where the air conditioning stops cooling after half an hour of operation. The most common cause is refrigerant leakage—the system can manage initially, but after half an hour, the loss becomes too significant to sustain cooling. Compressor overheating is another possibility; if the fan is dirty or heat dissipation is poor, efficiency drops after half an hour. Other issues include a clogged expansion valve or faulty sensors misjudging the temperature and shutting down the system. I recommend checking if the fan is running and feeling the condenser for excessive heat. If there's a strange odor, it might indicate a leak. Don't delay—take it to a professional shop right away. Driving without AC in summer is unbearable and can even affect safety. Regularly cleaning the radiator fins during car washes can prevent many of these issues.
I had the same issue with my car's AC before. It would start sweating halfway through the trip, and the cold air would be gone in half an hour. I suspect it's mostly due to insufficient refrigerant or poor heat dissipation. In summer, if the fan fails when the engine gets hot, the AC system can't handle it. I've tried checking the pipes under the hood for water stains, which are signs of leakage. A loose or worn compressor belt can also cause this—if you hear strange noises, check it immediately. Driving long distances with this problem is dangerous. Last time I didn't fix it because I was in a hurry, and I ended up with heatstroke. A reminder to everyone: open the windows for ventilation when parked, don't push through, and just have a mechanic check the pressure—it can solve the problem.
I've been driving old cars for decades, and when the AC system ages, it often stops cooling after half an hour. Usually, it's because the pipe seals crack, and the refrigerant slowly leaks out. Or the expansion valve gets stuck—after driving long in hot weather, the parts expand and block, cutting off the airflow. Dust buildup on the filter can also block the airflow, making the fan struggle to spin. I recommend getting the AC checked regularly during maintenance—don’t skimp on costs. Keep an eye on whether the condenser is icing up, as that’s a sign of low pressure. Delaying repairs can get expensive, and a broken car is even more trouble.
