Two times now after stating the motor and then turning on the A/C I've heard a pretty nasty crunch sound only at the first engagment. Guessing the clutch is the source and might be nearing a costly fix. Any comments or ides?

 

You might check the freon, could have too much in it. Thats about all that would be an easy fix.

 

My truck will also make a very loud noise as the clutch engages after not being used for
a day or so. After the initial engagement it is quiet when turned on or off.

 

I've had the truck for about 16 months & 42,000 miles. I'd think the charge would be less than when new.

 

If that is just the thump noise when it starts the first time that is normal, but I got the impression that he was talking about a chattering or grinding when it engages.

 

Yes, the first time this happened the truck was not drivin for 24 hours (not commen).

 

Oh no, this is not normal!

 

Mine does same thing after no usage for a long period.When I bought mine in the heat of the summer and test drove several new ones they ALL did it ac first turned on.After use and reusing ac they did not do it.Another thread on TDR is addressing same thing.Its normal.Why I don't know but it seems after a period of non use you get a big THUNK ac turned on.

 

Yes it's normal, they have been doing this for a long time. Even my 01. Only thing I can think of is that the a/c pressures in the compressor probably rise very quick on the diesel engines. On a gas truck you turn on the a/c and it will slow the engine. Obviously that's not happening on our Cummins engines.