Report: Failure of AC Compressor Clutch
Kia Spectra5 Problem
A defective AC compressor clutch assembly can cause excessive noise or vibration when the air conditioning is on. Improved parts are available. Replacing the faulty clutch assembly does not necessitate replacement of the complete AC compressor or evacuation and recharging of the air conditioning system.
Visitor, 2005 Kia Spectra5
Sounds like a loose belt - but it was he clutch assembly