5 Signs Your Car Air Conditioning Compressor is Failing

As summer temperatures rise, a functioning car air conditioning (AC) system becomes essential for comfortable driving. The compressor is the heart of your car’s AC system, circulating refrigerant and maintaining the system’s pressure.

When the compressor starts to fail, it can significantly impact the AC’s performance. Recognising the signs of a failing compressor can help you address issues before they lead to more extensive and costly repairs.

Here are the 5 most common signs that your car air conditioning compressor is failing.

1. Unusual Noises

Grinding or Squealing Sounds

One of the first indicators of a failing AC compressor is unusual noises coming from the unit. If you hear grinding or squealing sounds when the AC is turned on, it could be a sign that the compressor’s internal components are worn out or damaged. These noises often result from failing bearings or a lack of lubrication within the compressor.

Clunking or Rattling

Clunking or rattling noises can indicate loose or broken parts inside the compressor. This could mean that the compressor is no longer functioning properly and may soon fail completely.

2. Reduced Cooling Performance

Weak Airflow

If you notice that the airflow from your car’s vents is weak or not as strong as it used to be, this could be a sign that the compressor is failing. The compressor is responsible for maintaining the pressure required to circulate the refrigerant. When it starts to fail, it can’t maintain the necessary pressure, leading to reduced airflow.

Warm Air

When the AC blows warm air instead of cool, it’s a clear indication that the compressor is not functioning effectively. This happens because the compressor can’t circulate the refrigerant properly, preventing the system from cooling the air.

3. Fluid Leaks

Refrigerant Leaks

A failing compressor can lead to refrigerant leaks. If you notice oily spots or puddles under your car, especially near the front, it could be refrigerant leaking from the compressor. Low refrigerant levels can cause the AC to blow warm air and reduce the system’s overall efficiency.

Oil Leaks

In addition to refrigerant, the compressor contains oil that helps lubricate its moving parts. A failing compressor might leak this oil, leading to reduced lubrication and further damage to the internal components.

4. Electrical Issues

Compressor Clutch Not Engaging

The compressor clutch allows the pulley to engage and disengage from engine power so that the compressor is only running when it needs to. If the clutch is not engaging, it could be due to an electrical issue or a failing compressor. Without the clutch engaging, the compressor won’t be able to function properly, resulting in a lack of cooling.

Blown Fuses or Tripped Circuit Breakers

Electrical problems can also cause the AC compressor to fail. If you find that the AC system is blowing fuses or tripping circuit breakers frequently, it could be due to an overworked or failing compressor drawing too much power.

5. Unpleasant Smells

Burning Smell

A burning smell coming from the AC vents can indicate that the compressor is overheating. Overheating can result from internal damage or insufficient lubrication, and it can lead to a complete compressor failure if not addressed promptly.

Musty Odor

A musty odor could be a sign of moisture build-up due to a malfunctioning compressor. This moisture can lead to mold and mildew growth within the AC system, which not only causes unpleasant smells but can also affect the air quality inside your car.

Getting Unpleasant Smells With Your Car Cabin?

Read our “8 Potential Causes For Smelly Car Cabin” Article.


Recognizing the signs of a failing car air conditioning compressor early can help you avoid complete system failure and costly repairs. If you notice any of the above symptoms, it’s crucial to have your AC system inspected by a professional mechanic.

Regular maintenance and timely repairs can extend the life of your compressor and ensure your car’s air conditioning system remains in top working condition, keeping you cool and comfortable on the road.

Not sure what’s wrong with your car air conditioning system?

Read our “Ultimate Car Air Conditioning Fault Checklist” to help you narrorw down the problem.


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