I have 1991 C1500 extended cab with 101,000 miles. I’m going to replace the A/C compressor for the 2nd time in less than 1 ½ years. The factory A/C made a growling noise when the clutch was engaged ever since I bought the truck in 2000 with only 38,000 miles. I was told that the noise was common for the 91 trucks. How could something that sounded like it was about to fly apart be common? It always cooled & the noise never got any worse. Others finally convinced me that the compressor needed changing. So in May 2005 I change the compressor (reman – manufacture unknown), accumulator, and orifice tube @ a cost of around $550. On start up with new compressor installed & clutch engaged, I got the same growling noise but it was a lot quieter than the factory compressor. I started trying to pinpoint the noise, thinking it might not be coming from the compressor. I ended up replacing the, belt tensioner, serpentine belt & fan clutch. I have checked all belt pulleys. The noise is only there when the clutch is engaged.
The noise inside the new compressor has gradually gotten worse. The noise now is at an all time LOUD!! I’m going to replace it all again. This time with a new compressor. I WILL NOT put another OEM compressor in. I’ve seen Four Seasons, Visteon & Ready-Aire. I know nothing about a good compressor brand. What is a quality compressor that I can put in? I don’t care what it cost, I’ve been listening to that noisy compressor for 6 years now & I plan on keeping the truck a while. Some of you A/C guys help me out here.

Thanks,
Willie

Make sure the compressor has all the necessary braces. Several GM models have had compressor "groan" or "howl" due to inadequate bracing, resulting in the compressor vibrating on its mounts and creating a harmonic noise. If you can start the engine and SAFELY work around the compresor with it running, you might try to loosen a mounting bolt or two and see if the noise changes. That would be an indication of a mounting issue. Early Astro vans with the 262 V-6 suffered from this, and had a factory add-on reinforcement brace as a solution. Early 1980's F-Cars with V-8s had a similar problem, and also required a factory add-on bracket to solve the issue. You might want to check the mounting bolts for the entire accessory mount bracket to make sure they are tight, too.

I would stay away from any reman compressor. The best new brand is factory delphi, you can purchase them from Carquest or Federated parts stores.

Blue Bowtie, I'm gettin ready to do some PM on the truck. I'll check the brackets & braces too see if any are loose or broke. This is something that I haven't thought about.
horse482, I took a Delphi off. If the problem comes down to the compressor, I want get burned by the same product twice.

Thanks for your comments,
Willie

To get the same compressor it is going to be a Delphi, regardless wether its reman or new.

It was a loose bolt on the bracket!! Tighten the bolt by the idle pulley on the passenger side & the noise completely stopped. I have had this noise for six years. Changed the compressor a year ago, thinking the noise was coming from the compressor. Was about to change the compressor again.

Thanks everyone for your help on this one.

Willie