My a/c compressor is making a rattling sound every time I turn it on.
My car has 121189 miles.
My car has an automatic transmission.
There may be a few reasons your compressor can rattle. First the noise will have to be determined to be internal or external to the compressor. If the noise is internal then it is most likely a bad compressor. If the noise is external then you may have a bad tensioner or pulley when under a load. A internally noisy compressor can be due to lack of oil in the compressor and is going bad. If you decide to get this fixed, consider YourMechanic, as a certified professional can come diagnose the issue with your A/C and help you fix it accordingly.