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1991 chevy Blazer A/C compressor confusion

My belt was making a screaming squeeky noise to wake up the dead. I used dish soap on it and it got quiet as long as I remember to bring the dish soap.My mechanic looked at my AC and told me I need a new compressor (he is a friend I trust) Now the AC comp turns but the belt seems to go on and off. And, the weird thing is-the AC feels great! Am I to expect any moment for it to just stop working? Auugh hate to spend the money that he charges when he avoids telling me the price but he implies it is a lot! So, what to expect from my dead or dying compressor?

The compressor clutch cycling on and off is normal for your vehicle. That’s because the AC system in your vehicle is called a CCOT or Cycling Clutch Orifice Tube system.

Nothing to worry about.


Wash the dish soap off the pulleys, chnage the belt, and see what happens. My guess is that the compressor is intermittantly binding (the bearings may be failing). The soap stopped the squeal by allowing it to slip, and now there enough soap built up on it to allow it to get off the pulleys. Soap and fanbelts do not go well together.

Ok the soap wears off by the next day. By the way the squeeling squeek is only when I put on AC so it has something for sure to do with it. I guess there is away he did check the bearings therefore he pronounced the compressor dying? I had it on today which was the hottest this year and it cooled darn well! I will ask him straight up why thinks it is my compressor when it seems to work fine (I did notice the compressor would turn for a few seconds now and then as you said about a CCOT but it is weird because the belt seems a full 1/4 inch away when it kicks in for those few seconds. In the meantime I’ll look for prices on anew or used one and enjoy the cool whilst I have it-Thanks for helping even if I’m still confused maybe I word this poorly when all I seem to want to know is “does an AC require the compressor to function” and if so “How can one tell it is broken or about to be broken?”

You know what it sounds like? The compressor clutch bearing going out.

If you can get an AC compressor clutch kit or just the bearing and prevent the bad compressor clutch bearing from damaging the compressor, the compressor will last a good long time.


After reading what you wrote exactly. I am thinking the compressor is a red herring. I thing you may have a bad belt tensioner. The AC compresser is hard to turn when it engages. I think the tensioner is putting enough tension on the belt to not slip with the compresser off and then start slipping when you turn it on. It’s also possible your belt us old and streched. I would start with a new belt first as it’s the cheapest if repairs. Otherwise tester can be 100% right.

In answer to your epcfic questions, yes the AC system requires the compressor to function, and you can tell if it’s broken or about to break because it becomes noisy when you turn the AC on. Or it simply binds up completely and the belt snaps. Noise will often take the form of a squeal because a binding compressor can make the belt slip, or it can take a sinister growling noise…like a bearing failing.

And I still suggest that you need to clean the pulleys and change the belt. Although the dis soap may have appeared to disappear, it got squashed into the belt and pulleys and I’ll bet it left residue.

OK will do. Funny the wheel on the compressor (where the belt wraps around or at least is supposed to) turns freely. I thought a broken one would not turn. Anyway still cranking out cold air

I left a message with my mechanic. He’ll let me know. I just wish I could find a cheaper fix. I saw on problem as being a relay switch but I’m sure he checked that for short circuit as he uses his electric “checker” a lot (a box with gauge’s that must show if the current is ok) I went out just now and “spun” the “clutch?” of the compressor and it freely spun-second after a really loud squeel after I started and put AC on then–no more moving and the belt is clearly 1/4 to 1/2 inch away, So I’ll tell him that it case it helps but he most likely wants me to go the more costly route. Thanks for your help I’ll get back next week after he fix’s it


Well I broke down and talked to the mechanic. He had to admit it may not be the compressor. The darn truck cools down not problem except the several seconds after turning on the AC

I try and catch it actually engaging but by the time I get out of my truck (disabled and kinda slow) the squeeling has stopped.

He told me he had a similar issue with another of the cars he see’s and in that case the AC worked for years so my current solution (up until it truly breaks down) Is to wait until I’m past my neighbors earshot, I’l turn it on!


So how old is the belt in all of this?

Why has he not looked at the tensioner??

Good point I’ll insist he replace it. The last thing he replaced was the starter and that was the original (he said) I doubt the belt is but replacement seems prudent-thanks

Does your vehicle have a single serpentine (flat) belt that drives everything or does the A/C have a separate “V” belt all its own??

I bet the squeeling has to do with the belt and/or the tensioner. Do not let anyone sell you a new compressor. (unless all else fails).

Thanks EllyEllis and Caddyman

To the latter, it is a single serpentine belt and there is a “pick up” for lack of a better word that spins on occasion (maybe when it is charging) Kinda weird looking set up near the compressor but…

Still icy cold. My mechanic by phone told he he had just junked a blazer and wish he’d taken that compressor out ( ??? mis communication or perhaps he wanted to sell me that which I may not have needed) in any case his words now are “So it makes noise, it goes away-I’ve had guys with cars like that with it lasting the life of the car”

So, it is NOT the compressor. With that in mind instead of soap or sprays or dressings for the belt, I diluted 2to1 laundry detergent and…Bingo! instant screeching for a second then, quiet! This “treatment” thus far did the trick! no squeeling or screeching noise over a week

Why did it work? My guess is the additives in the detergent have or at least used to have a lube component to add life to the washer and maybe this kinda of “lube” is what works on belts.

By the way, the belt was changed when he put a radiator in just before I bought it 10 months ago.

Thanks for all the help if my “fix” hits the fan (in a manner of speaking) I’ll sally up and admit failure but for now, I’m a car genius (who has a tough time finding the oil dipstick!

Glen AKA Billypilgram

Banging my head aganst the wall… WHY HAS NO ONE LOOKED AT THE TENSIONER !!!

Spraying laundry detergent on the belt… IS NOT A FIX !!

Ok I’ll ask him to look. I have moved away from his place and only go up once a week, so I’ll see him next week some time

OK then it’s not a fix but it no longer makes the noise and the car is still icy cool


Sounds like either a bad belt or tensioner. I’d try replacing the belt/tensioner before spending money on a compressor you may not need.