What are the reasons why the car air conditioner stops cooling after running for a while?
4 Answers
The reasons why the car air conditioner stops cooling after running for a while are: 1. Damage to the car air conditioner condenser; 2. Blockage of the air conditioner by foreign objects such as pollen or dirt particles; 3. Damage to the car air conditioner compressor; 4. Excessive use of in-car electrical devices leading to overload. The car air conditioner is designed to regulate and control the temperature, humidity, air cleanliness, and airflow inside the vehicle to an optimal state, providing a comfortable environment for passengers and reducing travel fatigue. The car air conditioning refrigeration system consists of components such as the compressor, condenser, receiver-drier, expansion valve, evaporator, and blower, all connected by copper or aluminum pipes and high-pressure rubber hoses to form a sealed system.
There are quite a few reasons why a car's air conditioning stops cooling after running for a while. The most common one is refrigerant leakage. When the Freon in the system is insufficient, it leads to intermittent cooling performance. The compressor could also be problematic - issues like clutch slippage or electromagnetic coil failure may allow it to work initially but stop supplying cold air after running for some time. Clogged condenser or evaporator can cause similar symptoms, as excessive dust accumulation leads to poor heat dissipation and triggers overheating protection shutdown. I once encountered this situation while driving, and it turned out to be loose pipe connections causing gas leakage. After repairs and refilling the refrigerant, it worked fine. Another possible cause is moisture in the AC system forming ice that blocks the expansion valve, causing the AC to automatically stop cooling after a few minutes of operation. I recommend regularly checking pipe connections for oil stains and performing professional cleaning to prevent dust buildup, which can help reduce the occurrence of such malfunctions.
I once had this exact issue with my car's AC—it would stop blowing cold air after about ten minutes of operation. Turned out the cooling fan had failed, and the radiator fins were so clogged with dirt that heat dissipation was compromised, triggering the compressor's overheat protection shutdown. Aging compressors or faulty pressure switches are also common culprits. If the high and low pressures become unbalanced during AC operation, the protection system will automatically cut power. Another possibility is relay failure, as electrical components tend to develop poor contacts over time. The mechanic taught me a DIY trick: first check if any fuses are blown, then inspect whether the AC filter is clogged—these simple steps can save you money. Additionally, regular replacement of the receiver-drier is crucial, as it absorbs moisture and prevents ice blockages.
When air conditioning cooling is interrupted, thermostat failure is one of the common issues, with sensor false alarms causing the system to shut down prematurely. If the compressor is operating but circulation is poor, the cooling effect will disappear. Aging electrical wiring or loose connections may also trigger the protection mechanism to automatically shut down. From my own experience, air mixing into the air conditioning system causing ice blockage is one of the reasons. It is recommended to stop and check in such situations to ensure the fan is rotating normally.
