AC unit knocks and rattles when turned on on 2008 Kia Sorento

when I turn on A/C my car makes a horrible rattling and knocking. Sometimes it cranks rough as well and when it does that it runs rough for the first minutes

by in Chandler, AZ on September 09, 2009
1 answer
ANSWER by , January 19, 2010
Sounds like the AC compressor clutch is failing, how does it run with the AC off?