When my AC cycles on there is a loud rattle coming from the compressor pulley. So something on the inner pulley is rattling because the sound goes away when it is free flowing (AC off). Is this just a common rattle or is it something bigger? Does anyone know exactly what is rattling? Thanks

 

JJT,

You'll have to try to isolate the noise a little better. It's possible the noise could be the clutch, or more likely the compressor itself. Has the system been serviced lately? Was oil added?