Having truble with the acc belt. thought that the a/c compressor was freezing, might still be. diconected the power to the engaging unit on the front and check the pulley seems ok when there isn't any tention on it. drove the car a bit and seemed ok. Stoped to check that everything was ok, found that the a/c pulley stoped again. Now here is where I get lost in this. If I undo the tentioner shock the pulley seems to turn ok. not sure what to do. Is there a barring in the a/c compressor pulley that might be shot and when under higher tention does not turn or do I have a problem with my tentioner? Any help would be great.

You should put this in the diesel discussion section, its not a performance tuning issue.