97' GT (Noise coming from front belt tensioner)

[Tplayer]

I took my 1997 Pontiac Grand Prix GT in a garage because I was hearing a very loud grumble coming from my front belt tensioner pulley. While the car was running you could actually put two fingers on it and feel it vibrating and knocking.
The noise was much louder once you put the car in drive than when it was in neutral or park.

The pulley was replaced along with the rear tensioner as well. Once we started up the car and drove it the same vibration and loud sound returned. Thinking it was a defective pulley they had their courier pick up another one and replace it again. The same sound instanly returned.

Finally I took my car to the dealer where I bought it and was told that the problem was not the pulley but the supercharger nose drive. They said there were some bearing that were probably bad and the noise and vibration was transferring to the tensioner.

They wanted $400.00 for the nose drive and $300.00 to put it in. I decided to buy the part from another source and have Fletchers put it in. They had a hot shot mechanic there that use to work for GM so I went a head and let him install it.

He seemed to do a good job putting it in but it didn’t’ solve the problem. The front belt tensioner is still rattling and making a loud sound. It doesn’t seem to affect the performance but it’s really annoying. Does anybody have any ideas as to what it could possibly be?

Here is a picture of my tenioner. You can see the new nose drive, and alternator too. The green arrow shows exactly where the noise is coming from. Remember this also is new.

[Ripn12s]

First thing, take the supercharger belt off and start the car. Is the sound gone????

You said you had the rear tensioner replaced, did you have the one that the arrow points to replaced????

[Tplayer]

To answer your first question, I have not tried to remove the supercharge belt yet. That is a good idea, I will do that as soon as possible. If I remove it and there is no more noise what does that tell me?

I did in fact replace the front tensioner where the arrow is pointing, two times. To tell you the truth, I don't know why they replace the rear tensioner. I told them and showed them where the noise was coming from which was the front pully. For some reason the mechanic thought I was talking about the rear. Nevertheless, he did replace them both.

Again, once you put the car into drive, the noise doubles in volume and you can litterally feel the tensioner knocking and grumbling.

I spoke to the dealer again today. My service tech told me to bring it in and they will touble shoot the noise for half the regular cost. I think he may feel a little bad for telling me it was the nose drive when in fact it wasn't.

Well see how it goes.

I am still interested in any other thoughts you may have.
Either way I will keep you posted in case someones has the same problem.
regards,
tplayer

[Ripn12s]

Taking the belt off will help in pinpointing where the noise is coming from.

If the noise goes away then you can safely say that the problem lies withing the SC belt system. You can turn the SC by hand and feel for any kind of slack in the gears also.

One thing also, what pulley r u running stock??

You might try running a smaller belt. My car would make a strange sound sometimes and I noticed that when the car would shake and lope (big cam ) the belt was too loose and the tensioner would you its full range of motion. I but a much tigher belt on and problem solved.

You'll also notice that the tensioner pulley is metal. See the idler right next to it the plastic one. You can buy another one of those from GM and use that on the tensioner. Its alittle bigger and will take up some slack in the belt. I've been runnig one for 4 months now and have no problems

[Tplayer]

Thank you for your suggestions.
You asked what pulley r u running stock??
I’m not quite sure I understand that question; I’m not a very promising mechanic. If you are referring to the tensioner, it’s just the factory pulley. The nose drive pulley is smaller than the factory, it’s supposed to increase the house power, although that wasn’t the reason I bought it. The noise didn’t just happen suddenly, it was very gradual becoming louder and louder as time went on.
Thanks for your feedback.

[Ripn12s]

The noise sounds like the bearings on tensioner pulley is going, but you've had those replaced.

On the SC the stock pulley size is 3.8
Most people run a 3.4 as their first upgrade

I run a 3.1

[Tplayer]

Well I just got a call from the dealer saying my car is ready. I can’t believe what he said the problem was. All that expense I went through replacing the tensioners and nose drive was for nothing.
He said it was an oversized belt that was causing the problem.
Apparently some time ago I must have had it changed and who ever put it on for me put on one size too big. They put on a smaller size and the noise went completely way.
Or so they say, I’m going to pick it up now.
I really feel like an idiot for spending all that money on time on parts I really didn’t need.
Even though they are more expensive, I think I will reconsider taking all mechanical problems straight back to the dealer.

[Ripn12s]

Man that sucks. Should of came here frist.

You might try running a smaller belt. My car would make a strange sound sometimes and I noticed that when the car would shake and lope (big cam ) the belt was too loose and the tensioner would you its full range of motion. I but a much tigher belt on and problem solved.

[Tplayer]

Well one good thing. With that new nose drive on there it really halls ass.
I'm not really a racer but I couldn't resist the challange from a red mustang that pulled up next to me at a light. It looked like a 2000 or so.
I pulled ahead and for about the first 300 yards and then chickend out.

Anyway thanks for your feed back. In my next thread I'm going to start I'm going to ask how much people think I can get for my car if I were to sell it on the street.

I have a high end sound system that cost me $12,000.00 to put in. Yes thats twelve thousand dollars. I dont' expect to recover that by any means but just wondering if it adds anything to the value at all.

I think I want to sell this thing and buy something more durable.

I'll post pictures when I get a chance.

[Ripn12s]

I think I want to sell this thing and buy something more durable.

A loose belt and you're ready to trade it in

3.8 is a good motor and your ahead of the game if you havent had to replace the trans.

Ive been through 3 trannies now, but Im not about to sell my car. I have stopped racing but I still love to drive the car.

If you do sell, I think you'll get more $$$ by parting out the stereo.