Horrible screeching / squealing noise - help!

Hey guys.

Don't know what to say about this problem exactly. It has me worried.

I heard a very strange scraping noise which I identified as snow built up in my wheel wells. Soon after, I notice that anything more than very light throttle causes an very LOUD screeching or squealing noise. Sounds like it's a belt, but also sounds like it could be coming from the supercharger, I have no idea.

I shut the car down, started it back up, and got the squealing at start, then it goes away. Any gas makes the screech. Shut it down, start it back up, and it has the screech again. I give it a decent amount of gas, and my LIGHTS start to go dim, sounds AWFUL.

Could this be the alternator going bad or something? I thought I heard some strange belt noise before, but now I'm not really sure of anything.

I dunno, if you guys could just give me a starting point.

Oh! The sound is almost like when you start the car, and then you don't think it's started and you try and start it again, making that horrible screeching.

Well, that's all the info I can provide. Thanks for any help.

Sounds like it might be a idler/tensioner pulley about to grenade. But if the lights are dimming that points to the alternator as a possible culprit.

If you can let it run long enough to get good and warmed up,after you shut it down feel of all the pulleys to see if one of them is very hot.

Bert

I agree. How many miles on the car?

Dude....wheres my cat?

Lord.

So anyway, the car has 66k on it.

I drove it to my mechanic and we took a look under the hood - sure enough, there's NO tensioner pulley. It's gone, and the bearing is just sitting there.

Yeah, so you guys were right. Should be a cheap fix.

That's the earliest I've heard of one failing. Usually they last to 85k at least.

Maybe the belt was was too tight, do you think?

I can't believe you guys nailed it.

Regarding comments from AA and 1995 Riv:

1. I replaced the tensioner pulley with the ZZP aftermarket one. It might not have been all that great, considering it only lasted about 10k miles.
2. The belt might have been too tight, making too much stress on the bearing causing it to eventually fail.. I can't remember if I got the smaller belt for the 3.4" pulley, I may have. And foolishly I also went with the 3.5" tensioner pulley - this would definately cause the belt to be too tight.

So I don't know for sure, but these are both good guesses. Heh, you guys are like detectives with this stuff!

I think this is also why I was losing power to my accessories. The belt was losing tension on the alternator causing it to not spin much, if at all. At least that's my guess.

I'm just really glad that the pulley didn't jam in the other pulleys and something REALLY bad to happen.

So the repair was only $50, and it now has the stock-sized tensioner pulley on there. Guess we'll see how it does! Thanks guys.

Hold up for a second... which tensioner pulley failed? The SC side or the accessory belt side? I assume you replaced the tensioner pulley for the SC belt, so that shouldn't affect the alternator or anything else.

Assuming you replaced the tensioner pulley, I'll buy into that ZZP tensioner pulley being bad product, but I don't think the added belt tension caused it. The pulley was crap - it failed. I got mine from INTENSE, which is OEM GM 3.5" tensioner pulley, and it's been on the car well over 100k miles, maybe 150k even.

I've had other pulleys frag, but that GM 3.5" tensioner pulley is good stuff!

Aaron,
Is the GM OEM 3.5" plastic or steel ?

Steel, just like the stock one. it's just bigger in dia.

Shoot, I just ordered a new 3.5" tensioner pulley and i don't think i asked for steel.
I guess I'll just put this one on the shelf and order one from Intense the next time i make an order from them.
i don't need it right away, just trying to get all my stuff together for when I install the GenV and 3.4" MPS.

You could also try GM parts direct. I think it's a $20 item.

A plastic tensioner pulley is pretty odd, imo. All of the smooth pulleys are usually steel because they contact the flat side of the belt. The idlers are sometimes plastic because they need to be grooved, but I've never heard of a smooth plastic tensioner pulley.

I was ordering some other stuff from Wbody store and noticed the oversized sc tensioner pulley.for 23.00. They have an option for steel or plastic and I made the order without checking off the steel option. My mistake.
I didn't notice my error until I got shipping confirmation from them.
I at least got free shipping and a complete 3.4" MPS for $65.00.

Well, now I feel like an idiot.

The tensioner pulley that went toast was the accessory side for sure. I actually didn't know we had two tensioner pullies. The 3.5" tensioner for the supercharger was definately steel, and I guess it's still fine. The stock accessory tensioner is the one went bad. But this raises the question - if the stock one went bad, how did a STEEL PULLEY go missing? Can it seperate from the bearing or what? Anyway who knows what happened. Any guesses?

Buapo wrote:

But this raises the question - if the stock one went bad, how did a STEEL PULLEY go missing? Can it seperate from the bearing or what? Anyway who knows what happened. Any guesses?

The pulley fell out without hitting anything?


The belt can't be 'overtensioned' because of the spring loaded tensioner. It's spring loaded to maintain the same tension at all times.

The whole pulley thing has been discussed thousands of times for the 3800s. This shouldn't be a big surprise. The big surprise is the cheapo bearing in the ZZP pulley, that surprises me.

I don't remember where the threads are with the part numbers, but just get the aftermarket Dayco pullies. They are steel and have good bearings.

Did the ZZP pulley fail? Is it a fact they use cheap bearings.?

AA wrote:

Did the ZZP pulley fail? Is it a fact they use cheap bearings.?

Sorry, my impression from the OP was that the ZZP pulley failed after 10K. If that's not the case please correct me.

Okay everyone: ATTENTION!

At first I thought it was the ZZP 3.5" tensioner pulley that failed. I WAS WRONG. It was actually the STOCK ACCESSORY tensioner pulley, not the supercharger tensioner pulley.

My previous post for those who overlooked it:

Quote :

The stock accessory tensioner is the one went bad.

I don't want ZZP to get any flack about a bad product (again), because they don't deserve it this time. It was a lack of knowledge on my part - I didn't realize we had TWO tensioner pullies (which makes sense because we have two belts... I just didn't think of it).

So to recap - it was my stock accessory pulley that went bad, not the ZZP supercharger tensioner pulley. The ZZP 3.5" steel tensioner is still attached to its appropriate location, and working just as well as it did when I first put it on 10k miles ago. No problems in sight.

Still have no idea how I lost a stock steel pulley. But the bearing was definately locked up, so who knows how that happened.

And YES, there is no trace of the pulley. I have no idea where it went, but I guess it didn't damage anything on its way out because everything else seems to be just fine.

I love a happy ending.......

OK Chicken - is the pic of the cat before or after the screeching?

Albertj

Buapo wrote:

Okay everyone: ATTENTION!

At first I thought it was the ZZP 3.5" tensioner pulley that failed. I WAS WRONG. It was actually the STOCK ACCESSORY tensioner pulley, not the supercharger tensioner pulley.

That's cool, sorry I misread. I'm glad to hear I was wrong.
-Derek

Chicken,
How did you get your pussy to smile like that.

Great photo, but tell us how..........

Does this mean the bearing was frozen to the shaft or just the shaft was tore up Ben?