Folks:

I had the A.C. charged and the initial little things done on 83 300SD, 160K miles. Intermittantly, I get a howling noise almost like something is functioning without any lubrication under the hood. I hear it at idle and it doesn't immediately stop when I shut the air off. It is intermittant, so it stops.

I think it's A.C. related because when I run without air at all, I get no noise even starting at all.

What's happening, compressor about to go? I'm inclined to just replace the compressor???

The old R-4 A/C compressors do make some noise when running. Did you hear this noise before?? Maybe you are not used to the new noise of a cycling compressor.

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Orland Park, IL
1985 300SD 215,000 miles

It's loud, I think maybe it was overcharged a bunch or is beginning to fail.

If it cycles this loudly, I'd be shocked. It actually is intermittant and is normal for a while and then ROAR!!!

Unless someone has a better suggestion, I'll take it to a buddy tomorrow and if it's not overcharged, I'll replace the compressor before it fails and blows gook all thru the system.

Thanks for the response.

Has anybody added any lube to a/c system? Oil trsavels with the freon in the system. So when you lose freon, you lose oil. People will replace freon forever without ever adding oil. Eventually you get a system with the proper charge and NO oil. My wife's 190E was a bad case of that. When I replaced her compressor (Nippndenso,ouch), I found the system was completely dry.