Why does the car air conditioner suddenly stop cooling and only blow air?
2 Answers
Reasons and solutions for a car air conditioner blowing air but not cooling are as follows: 1. Lack of refrigerant: Insufficient refrigerant in the air conditioning system leads to reduced pressure and less heat being carried away, giving the impression that the air conditioner is only blowing air. To check, observe the sight glass on the dryer tank. During normal operation, if there are continuous slow bubbles in the sight glass, it indicates insufficient refrigerant. If obvious bubble turbulence is seen, it means the refrigerant is severely lacking. The solution is to replenish the refrigerant. Note: If adding from the low-pressure side, do not invert the refrigerant bottle; if adding from the high-pressure side, do not start the engine. 2. Too much refrigerant can also cause the air conditioner to stop cooling: The proportion of refrigerant in the system must meet certain requirements. Excess refrigerant can affect heat dissipation, as can adding too much cooling oil during maintenance. Solution: Observe the sight glass on the dryer tank. If no bubbles are visible during operation and none appear after the compressor stops, the refrigerant is excessive. If the cooling oil is over-pressurized, turbid bubbles may be seen in the sight glass. If refrigerant is indeed excessive, slowly release some from the low-pressure side service port. 3. Loose compressor drive belt: A loose belt causes slippage, reducing transmission efficiency and compressor speed, which decreases refrigerant compression and delivery, leading to no cooling. If the belt is too loose, tighten it. If it cannot be turned by hand, it is too tight and should be loosened slightly. If tightening doesn’t work or the belt is cracked or aged, replace it. 4. Electrical issues: Many problems can cause the compressor to stop working, with electrical issues being common. A preliminary check can be done by directly powering the compressor’s electromagnetic clutch. Generally, compressors rarely fail directly.
Last year while driving, my car's AC suddenly blew only warm air, leaving me sweating profusely. Upon inspection, it turned out the refrigerant was leaking, possibly due to aging pipes or loose connections. The compressor wasn't even making noise - if the belt had snapped, it would've been a much bigger problem. My advice: first start the engine and listen for any clicking sounds in the engine bay; if the blower works but the air is warm, don't force it to avoid wasting fuel or damaging components. When I took it to the shop for refrigerant recharge, they also cleaned the condenser filter - afterwards the system worked like new. Remember: leaving such issues untreated creates a vicious cycle where the compressor might fail completely, making repairs much more expensive. Addressing it promptly saves a lot of hassle.
