Ok, initially I had a bad rattle at low rpm ONLY when the AC was on. I found the AC belt tensioner acting like a basketball when the AC was engaged, but just acting normal when the AC was not on. So, I replaced the tensioner, with a NON GM part, and the noise sounded different, but was just as bad. So I figured that because I used crap to repair the problem, that it was still the same problem, or a bad part. I went to GM, bought the proper part, and, you guessed it, the rattle is still there.

Now I am convinced that its the clutches in the compressor releasing and re-engaging really fast => Clutch chatter.

Is this a common problem? Is it rebuildable? Or is it smart to take the truck to the dealer and have them fix it?

What pisses me off is that I don't even use the AC or defroster that much.

BTW, this is on an 03 SSS.

 

You can probably find a reman compressor complete with clutch that won't break the bank, only thing is you have to recover the R-134A refrigerant you remove when disconnecting the ac lines (legally), then suck the system into a vacuum for 15-20 minutes to boil off any moisture, then re-charge the system with the proper amount of refrigerant.

 

I just went through this. It is your compressor. It will die soon. I went through a few tensioners and belts before it locked up ripping the last tensioner off leaving only the stud it pivots on still attached to the block. It is the low side valve or some sh*t like that going out. Get the new one from the dealership, they guarantee it for life. These are a bitch to change too, smaller shops usually keep the trucks for a couple of days if they don't do many of them. The only shop around I trust told me they did one and did not want to do another one... It cost me just over a grand, in case you are wondering, with another new tensioner and belt... My best advice is to bite the bullet and take it to the dealership, you probably have 500-1500 miles, from when it started, before it goes completely out so start saving now.