If my truck (07 3500 M/C) has been sitting a while and I start it and turn on the A/C shortly afterwards, I get a really loud "clunk" noise from under the hood. I assume it is the A/C clutch engaging but is it normal for it to engage that hard? If I have been driving for a while and turn on the A/C, the only noise I hear is the damper moving. Any help/clarification is appreciated.

 

Mine has done the clunk all it's life (72K miles) so far so good. The thing that makes me really nervous is every once in a while the a/c clutch will chatter really loud first engagement of the day.

 

My 06 M/C does the same thing with 36k and always has. I've seen other posts on here with at least a dozen replies and they all do it.