Why does the car air conditioner stop cooling after a while?
3 Answers
Possible reasons why the car air conditioner cools intermittently are as follows: 1. Overcharged refrigerant. When the car is driving at high speed, the rotation speed is fast, and the pressure of the refrigeration system is high. The pressure controller (pressure switch) activates, causing the compressor to stop and cooling to cease. When the car is driving at low speed, the rotation speed is slow, and the pressure of the refrigeration system is low. The pressure switch closes, the compressor resumes operation, and cooling is restored. 2. Dirty or clogged indoor unit filter. Open the panel and remove the filter. If there is dust on it, clean it with an old toothbrush in water and then reinstall it.
I encountered this situation last time where the AC was quite cool when starting the car, but after driving for a while, it stopped cooling. The most common issue is refrigerant leakage or insufficient refrigerant, causing low system pressure which leads to compressor shutdown. Another possibility is blockage in the AC lines, such as a dirty receiver-drier or a stuck expansion valve, affecting refrigerant flow. A condenser clogged with mud or leaves causing poor heat dissipation can also result in this, as high pressure triggers automatic system protection shutdown. If the compressor clutch is slipping or the AC pressure switch malfunctions, it can also cause intermittent cooling failure. If you face this problem in summer, it's best not to tough it out. Get it checked and repaired early—fixing the AC is much more cost-effective than suffering from the heat.
The air conditioning cooling is unstable; it's quite cool when first started, but becomes less effective after driving for a while. I suspect the following possible issues: First, check the heat dissipation effect of the condenser. If the radiator is blocked by insects or mud, it may cause the high-pressure protection to trip automatically. Second, the expansion valve may be malfunctioning, leading to uneven refrigerant distribution and temperature fluctuations. Third, air or impurities in the pipeline may cause the compressor to start and stop frequently. Additionally, the electric fan may not be spinning fast enough, or the clutch may not be engaging properly. During inspection, you can touch the air conditioning pipes. If they are frosted, it indicates insufficient refrigerant or a faulty expansion valve. If the high-pressure pipe is too hot to touch, it may be a heat dissipation issue. These problems require professional equipment for detection and repair.
