Hi, Ive seen a few similar threads on this but none specifically like my situation

When I first start my car (93 SDV 4.9L 93k miles) the belt or a pulley makes a squealing or chirping noise at idle and acceleration, no difference between the two, It squeals in park, reverse, and drive.. After driving about a mile or so I get a loud screech then the noice dissappears for the rest of the drive, the car runs very quiet and strong until it is shut off for awhile then on restart it all happens again. I am low on ac refregirgant so the compressor was shut off, I assume I can safely rule this out?

I cant remember exactlly when this started but its been a few months ago. If I recall I had the oil changed about the same time, after I got home from the oil change I popped the hood to make sure they installed a new filter and it was still smoking so obviously they spilled some. Also a few months prior to that one of the t-joints in the coolant line broke and sprayed the whole underside of the hood with anti-freeze causing a nice smoke storm, luckily I was only a block from home so I didnt need a tow . I didnt notice a night/day difference in noise after these 2 events but is it possible it just took a little while for them to appear?

I am going to listen and try to isolate the sound, but the fact that it isnt constant is going to make it a bit more difficult I believe.

Any ideas? I want to make sure im not putting off a cheap fix only to get a expensive one later on because of this. Would the fact that it stops a few mins after running help rule anything out?

your belts probably worn maybe your auto tensioner is goin out too

Yeah the tensioner has a little indicator on it. If the little arrow on it is past the box where the "good" range is, then it's up for replacement. Same thing if it's cracked a lot underneath. Also make sure there's at least a little bit of play in the belt, or the tensioner might need it, as mentioned. You might also get squealing if the belt was somehow over-lubricated or got a good amount of oil on it. You can clean that off by doucing it with silicone spray repeatedly and holding a rag against the belt, but if you do that BE CAREFUL not to get your hand or the rag caught in the pulley.

Guess Ill look into the tensioner, I looked at the belt the other day and it seemed very tight to me. If I do anyhting I will probably replace it over just cleaning it at this point. I dont think it has ever been changed to my knowledge, atleast not in the 5 years Ive had the car.

Thank for the help so far.

First thing to check is that tensioner pulley. Common failure on all GM products.

You mention that you're low on refrigerant. I'm not sure about '93, but in earlier Cadillacs, the refrigerant pressure assists in keeping the oil lubricating the A/C compressor bearings. If you use the Auto setting instead of Econ, even for heat, the compressor is activated. Even if it's off, the pulley still spins. It's possible your compressor is trying to tell you something. You might be able to bypass the compressor with a shorter belt. If the noise disappears you'll know, and then you can buy some time until you can get it recharged. It's a lot cheaper than a new compressor - trust me.

First thing to check is that tensioner pulley. Common failure on all GM products.

You mention that you're low on refrigerant. I'm not sure about '93, but in earlier Cadillacs, the refrigerant pressure assists in keeping the oil lubricating the A/C compressor bearings. If you use the Auto setting instead of Econ, even for heat, the compressor is activated. Even if it's off, the pulley still spins. It's possible your compressor is trying to tell you something. You might be able to bypass the compressor with a shorter belt. If the noise disappears you'll know, and then you can buy some time until you can get it recharged. It's a lot cheaper than a new compressor - trust me.
Noahsdad,

Have you tried to bypass the A/C compressor with a shorter belt? Looks like the water pump pulley won't get a good grip with a shorter belt.

Im not sure how the pressure is on the 93 either, I usually have the whole climate contol off, or on econ. I am getting the refregirant charged soon, I live in Texas and the windows down only works for so long :) so I dont think i'll try to bypass it. I guess when I get that done ill see what sort of shape the compressor is in, though it should be good. It has been low on refregirant for awhile so the compressor hasnt been used, not even for heat as I rarely use that in Texas.

I have tomorrow off from work so I plan to call up some a/c shops to charge it up and I will take a look at the tensioner pulley. I assume If I change the pulley I will need to take the belt off so should I just replace the belt while it is off or do they usually last longer than 5-6 years or 20-30k miles (how long ive owned it and about how many miles ive put on it)? Ill dig through my stack of maintance records from the previous owner who bought it used at a dealership. I would like to assume the dealer fixed the belt if it needed it, but I wont :)

If I take it off I think i will atleast give it a good cleaning with some instructions I found on here somewhere, since I know with the oil spill smoking and the blown coolant line It has most likely got alot of stuff on it that shouldnt be.

Noahsdad,

Have you tried to bypass the A/C compressor with a shorter belt? Looks like the water pump pulley won't get a good grip with a shorter belt.

My compressor seized before I got the chance, but I've read others on this forum who say they have made it work. I'm only assuming it's possible.

Im not sure how the pressure is on the 93 either, I usually have the whole climate contol off, or on econ. I am getting the refregirant charged soon, I live in Texas and the windows down only works for so long :) so I dont think i'll try to bypass it. I guess when I get that done ill see what sort of shape the compressor is in, though it should be good. It has been low on refregirant for awhile so the compressor hasnt been used, not even for heat as I rarely use that in Texas.

I have tomorrow off from work so I plan to call up some a/c shops to charge it up and I will take a look at the tensioner pulley. I assume If I change the pulley I will need to take the belt off so should I just replace the belt while it is off or do they usually last longer than 5-6 years or 20-30k miles (how long ive owned it and about how many miles ive put on it)? Ill dig through my stack of maintance records from the previous owner who bought it used at a dealership. I would like to assume the dealer fixed the belt if it needed it, but I wont :)

If I take it off I think i will atleast give it a good cleaning with some instructions I found on here somewhere, since I know with the oil spill smoking and the blown coolant line It has most likely got alot of stuff on it that shouldnt be.


The problem is that when the refrigerant is low, the compressor isn't being lubricated properly, which shortens the bearing life. I think the owners manual even has a warning about not engaging the compressor if the ref is depleted.

You can probably change the tensioner without taking the belt completely off. Just insert a 1/2 inch breaker bar into the square to release it. As long as you don't see any deep cracks when you flex the belt, it should be good. I think the life expectancy is about 50-60k. They're not cheap though, my last one was $56.00.

If you clean it, don't use any kind of slippery soap or oily cleanser - then you will have a squealer! :bigroll:

Yeah the tensioner has a little indicator on it. If the little arrow on it is past the box where the "good" range is, then it's up for replacement. Same thing if it's cracked a lot underneath. Also make sure there's at least a little bit of play in the belt, or the tensioner might need it, as mentioned. You might also get squealing if the belt was somehow over-lubricated or got a good amount of oil on it. You can clean that off by doucing it with silicone spray repeatedly and holding a rag against the belt, but if you do that BE CAREFUL not to get your hand or the rag caught in the pulley.

Could you help guide me to where this indicator is? I havent done any work like this before. I thought that once I got out their and looked at it, it would stand out but I am not seeing it. I looked on the forums for a picture but didnt find one.

Thanks.

Typically, there is a triangle on the tensioner arm & square on the body (or the other way around). It's common for a tensioner to freeze in one position because it doesn't move much. If it does freeze, as the belt stretches, you'll get a squeel. If the belt's been screaming this long, I'd just replace it (the one for my 4.5 cost about $30 I think). It's probably glazed.

With the belt removed, you can try spraying some lube into the gap between the arm & body of the tensioner, then with your 1/2" breaker bar work the tensioner back & forth til it moves smoothly & freely. Install the new belt & you should have no more noise/screaming.

Typically, there is a triangle on the tensioner arm & square on the body (or the other way around). It's common for a tensioner to freeze in one position because it doesn't move much. If it does freeze, as the belt stretches, you'll get a squeel. If the belt's been screaming this long, I'd just replace it (the one for my 4.5 cost about $30 I think). It's probably glazed.

With the belt removed, you can try spraying some lube into the gap between the arm & body of the tensioner, then with your 1/2" breaker bar work the tensioner back & forth til it moves smoothly & freely. Install the new belt & you should have no more noise/screaming.

OK I saw the tensioner and it had 2 squares, one on the arm and the body. It also had the words "Operating Range" on it. The 2 squares line up pretty well and over 90% of it is in the operating range, I guess this is what I was looking for, maybe all I need is a new belt then? I guess thats a good place to start if you think I would need one anyway since its been screaching for atleast a month or two. It might be a few days before I can get to it so any ideas/tips before I do are still welcome

Thank You all.

A three feet stick/rod will help you to put the belt on pulleys you cannot reach with hand.

A three feet stick/rod will help you to put the belt on pulleys you cannot reach with hand.

And if you find yourself swearing with this method, just jack up the front of the car, remove the right wheel, and then the plastic cover behind it. This will give you some access underneath...just in case it drives you nuts the other way.

Just getting back to this problem after all these months, thankfully with a bit more automotive knowledge.

I never got a chance to play with it after all the suggestions, but I reread it and will keep them in mind. I appreciate them all.

I got another oil chnage as I am now over 96k The tensioner is in the operating range but its still the same belt, recently the noise hasnt gone away when warmed up, the place that did my oil change said they think something is wrong with my power steering pump, and that it is causing the noise.

Along the same lines I recently started hearing a creaking noise when I turn sometimes; so I popped the hood and let it run, put a screw driver on the power steering fluid tank and I could hear it. I think that is causing atleast some of the noise, maybe the old noise was just a warning sign, the same shop also said my belt looked worn, If it wasnt worn at the time of the original post I am pretty sure it is now, lots of little cracks on the sides.

Their is plenty of power steering fluid so I imagine the pump is just on its last legs. Toward the end of this week I plan to atleast change the belt and will look into rebuilding/replacing the ps pump. Also I see that their is now a anti freeze leak on the side of the engine which I can only assume is the water pump, Is a little leakage normal or is everything going out at once?

I need to research a bit more, but I imagine to replace the ps pump the belt needs to come off, like the water pump. So when I replace the belt it might be better to replcae the pumps to save myself from taking it off again in the near future.

Any advice for the ps pump? Anyone rebuild thiers or is it cheaper to get a new one in most cases?

Same shop also said he could feel a miss, I sort of blew that off, but I can really feel it missing now so I may be replacing the plugs at that time aswell (wires/cap are pretty new)

Thanks to everyone, maybe after these fixes my car will sound like a cadillac, not a piece of crap :)
And I plan to never get another oil change as that seems to cause problems all the time ... Just kidding :)