Car Air Conditioning Stops Cooling After a While

[McEmma]

Car Air Conditioning Stops Cooling After a While The reasons and solutions for a car air conditioner that stops cooling after a while are as follows: 1. Too much refrigerant. When the car is driving at high speed, the engine speed is fast, and the pressure in the cooling system is high. The pressure controller (pressure switch) activates, causing the compressor to stop, and the air conditioning cooling ceases. When the car slows down, the engine speed decreases, the pressure in the cooling system drops, the pressure switch closes, the compressor resumes operation, and cooling is restored. Hence, the cooling is intermittent. 2. Lack of Freon. The usual cause of this issue is a leak in the air conditioning system's pipes. To detect the leak, you can drip some water at the refrigerant pipe joints of the car; bubbles will appear at the leaking spot. Once the leak is found and repaired, you can visit a professional car repair shop or a 4S store to add Freon.

[StQuinn]

I repaired a car with the same issue last week. Usually, the A/C is quite cool when first started, but after driving for twenty minutes, it starts blowing hot air. This situation is most likely due to refrigerant leakage or insufficient refrigerant; if the pressure in the A/C system is too low, it will stop working. A malfunctioning cooling fan or a condenser clogged with leaves can also cause the A/C to overheat and shut down as a protective measure. Another common issue is a faulty evaporator temperature sensor—if it falsely reports high temperatures, the compressor will shut off prematurely. When I was adding refrigerant to Old Zhang's car last time, I noticed oil stains at the low-pressure pipe connection, and sure enough, testing confirmed a leak. Remember, never add refrigerant yourself haphazardly—take it to a shop to have it checked with a pressure gauge; otherwise, you might waste money and damage the compressor or piping.

[DelNicole]

When encountering intermittent AC issues, prioritizing a check on the cooling system is always the right move. My go-to method is feeling around the engine bay—after turning on the AC, touch the condenser pipes. If only half is cool while the other half stays warm, it usually indicates low refrigerant or clogged cooling fins. A seized electric fan often triggers fault codes on the dashboard; using an OBD scanner to check data streams will reveal abnormal fan speeds. A faulty compressor clutch is another common culprit, with clicking noises being a telltale sign. Replacing the receiver-drier and flushing the lines simultaneously can keep things running smoothly for 3-4 years, far more cost-effective than just topping up refrigerant.

[HZoe]

Don't rush to replace the compressor if the AC suddenly stops cooling. I've encountered cases where the expansion valve got stuck - when the valve core gets clogged with debris, refrigerant flow decreases and vent temperatures gradually rise. A faulty temperature control switch can also send incorrect shutdown commands; a simple test is to submerge the switch probe in ice water to check its response. Also, a reminder: don't set automatic AC to 16°C at maximum blast, as evaporator icing may trigger protection - setting to 22°C with medium fan speed actually provides more sustained cooling. For loose pipe connections or leaks, using UV light with refrigerant dye is the easiest way to locate leaks.