I have a 2002 Chevy Trailblazer ltz with the 4.2 I6. I have been hearing a whining noise for quite awhile now. I took the idler pulley off, and it was fine. I finally narrowed it to the a/c. When I take the belt off the noise stops. It also gets quieter when the a/c is on. So it is obviously the a/c clutch bearing. Is that replaceable without evacuating the a/c and having to recharge it? I was thinking about tryng to fix it myself if it doesn't need to be evacuated and charged. Thanks for any help.