What to Do When Your Car’s Air Conditioner Stops Working


If you’ve ever sat stranded in an endless traffic jam baking away on a 100-degree summer day without air conditioning, you’ll agree that a functional AC system is essential. Yet unlike many simple repairs, automotive AC systems are often misunderstood and can be costly to fix. If something goes wrong, a little familiarity with your AC system will help you understand the severity of the problem when talking with your mechanic and can save you money on the repair.

What Are the Common Signs of a Broken Air Conditioning System?

With its fan at full blast, a properly functioning AC system should be able to cool the air in your car at least 40 degrees. If you’re noticing a lack of cold air coming from the dashboard vents, your air conditioner is probably malfunctioning. In a broken system, the airflow may fluctuate from hot to cool before becoming hot again.

Noise under the hood when turning the AC on or off, such as clattering components or a squealing belt, is another symptom of a problem. Even if you still have cold air blowing, this noise could signal trouble with the air conditioner’s compressor.

Why Did My AC Break in the First Place?

The AC system is sealed at the factory with a precise amount of refrigerant, known as a “charge.” The required refrigerant charge is under pressure at all times, so if there’s a leak, it will escape the system. Once the refrigerant has escaped, your AC system won’t be able to cool the air. Often, the age of the AC system contributes to leaks. Even if you stay on top of routine maintenance, older cars are more likely to suffer from leaks due to their long exposure to heat, vibration, and general wear and tear.

Older cars might also have issues with the compressor. The more miles you have on your car, the more wear and tear the compressor’s components have experienced.

Road salt has a degrading effect on AC systems. Corrosion from road salt can cause leaks in an otherwise perfectly operating AC system.

How Much Is This Going to Cost Me?

First: Avoid the temptation to service your own AC. Environmental regulations must be followed, and specialized equipment is required to service an air conditioner correctly. The DIY recharge kits found at auto parts stores may help in the short term, but improper service could damage the system or mask a serious problem, leading to a more expensive repair.

If your AC system is low on refrigerant, a technician will add new refrigerant and check for leaks using a specialized sensor. If no leaks are found, a system check and recharge may cost only around $100. But generally, AC systems shouldn’t need periodic recharges, so if your mechanic is regularly recharging your AC, there is almost certainly a larger underlying problem.

If your mechanic finds a leak, the leaking component will need to be replaced. AC components are located throughout your car, and the complexity of the layout will vary by car model. For instance, the compressor may be attached to the engine, but the condenser could be near the radiator at the front of the car, and the evaporator is often behind the dashboard. Lines, valves, and sensors run throughout the vehicle, connecting everything. Since it’s harder to access the various components on some cars, the repair cost may vary dramatically from model to model.

If a technician finds that your AC compressor is malfunctioning, your whole AC system may be contaminated with rust or metal particles. To fix it, a mechanic will have to flush it out, which can get expensive. Having your system serviced at the first signs of a problem can reduce the risk, although it’s not cheap: Replacing the compressor and flushing the system can cost over $1,000.

The best advice to ensure getting a fair price on an AC repair is to comparison shop—always get several estimates. The AC repair market is competitive in most areas of the country, and the effort of shopping around can lead to a smaller bill.

The Bottom Line

Don’t let your AC system remain inoperable indefinitely, as it could deteriorate without refrigerant, further complicating the eventual repair. But in most cases, it’s safe to continue driving your car in the short term while seeking multiple estimates. Finally, always ask for written documentation from the AC technician that the problem is fixed—if the problem comes back, you want to be covered.

A functional AC system is an important part of your driving experience. Paying attention to the performance of your AC and shopping around for a prompt, fair-priced fix at the first sign of trouble will save you money in the long run.

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