What is the cause of your AC compressor squealing?

1. Low refrigerant: This is the most common cause of AC compressor squealing. When there is not enough refrigerant in the system, it can cause the compressor to work harder and overheat. This can lead to the compressor squealing.

2. Compressor failure: If the compressor is failing, it can also start to squeal. This is because the compressor is not able to compress the refrigerant properly, which causes it to overheat and make noise.

3. Bad compressor clutch: The compressor clutch is responsible for engaging and disengaging the compressor. If the clutch is bad, it can cause the compressor to squeal when it is engaged.

4. Worn serpentine belt: The serpentine belt is responsible for driving the compressor. If the belt is worn, it can cause the compressor to squeal.

5. Loose bolts or screws: If the bolts or screws that hold the compressor in place are loose, it can cause the compressor to squeal.

Note: If you hear your AC compressor squealing, it is important to have it inspected by a qualified technician as soon as possible to prevent further damage to the system.