Ok so let me first build the background. The car has 134k miles on it currently and gets regular oil changes. I noticed back in September of last year that there was a noise that sounded like a bad bearing coming from the car during certain throttle conditions. The clutch had never been replaced up until that point so I figured (and had a few friends agree with me) that it was the throw-out bearing. So I had the clutch replaced that same month with an Exedy OEM. The noise got quieter but didn't go away completely. So at this point I was confused. I would describe the noise as a buzzing / metallic rubbing sound, like that of a bearing thats bad. Its only present during throttle conditions where I am not accelerating or decelerating. Motor sounds normal and pulls strong unless its in the in-between state where its not increasing or decreasing RPMs.

Fast forward 10k miles to last month. I finally got tired of listening to it and decided to start replacing things that would probably cause such a noise. So I purchased new motor and tranny mounts thinking that would surely quiet it down. Well...it got mostly quiet for the first couple days and then the noise came back. While changing my serp belt (not due to the noise but because it was just worn out) I checked all the pulleys for play or noise. They all turn smooth and theres no play in any of them besides the auto tensioner pulley. When I put pressure on the top and bottom it can wiggle probably 1-2mm or so back and forth.

Now through my research I've narrowed it down to either the auto tensioner pulley, idler pulley, some form of clutch buzz, or thrust bearing. I'd prefer to not just throw money blindly at the car in an attempt to cure the noise, because at this point I'm already out $1000+ from doing so. Am I looking at the right parts? Anybody else experienced this or have any insight into what the noise may be coming from?

Thanks!

 

I stole this idea from billman: You can take the drive belt pulleys out of the equation by simply removing the belt and running the car for a few minutes. Just make sure not to overheat it.
I've always found it really hard to duplicate noises/rattles on pulleys without the motor in action and the drive belt on, even ones that are known to be bad.
I assume you are aware of the tct problem and it's not that noise. Besides that, I'd get a mech stethoscope and start poking around to pinpoint the location a little better. Though If it's in the motor, it makes it hard to get an exact location.

A good quality video or audio of the sound might help.

 

I've replaced the TCT before, so I'm familiar with the noise. And I also did try the belt trick, but its impossible to simulate the noise when theres no load on the engine. Which also makes it impossible to use a stethoscope unless someone decided to sit in my engine bay while I drove around

 

You can safely drive around without the belt as long as its only a few minutes. To be extra safe, if you know anyone with a scan gauge , you can monitor temps in real time to make sure it doesn't get too hot.

When I re-read your post, I get what you're saying a little more now. I originally thought the sound was happening at idle.

 

A video would help...some problems make certain noises that we can help with a video or audio clip.

Have you checked to make sure nothing is loose? I know you said it was a buzzing sound, but could it be more of a rattle? I had a rattle occur on me out of the blue on Friday morning (last week). Let the car cool down and started working through every possible item that could get loose. When I jacked the car up, found that the secondary bank O2 sensor was loose on my test pipe. Tightened it up and was good to go.

Just a thought...

 

Ok I'll drive around my complex with the belt off to see if it makes the noise, and while I'm at it I'll try to get a video. Now if it would only stop raining...

 

Finally got around to testing this out.

Took the belt off and drove it around my complex, but the noise is still there. It may be slightly less significant or I could be imagining it, who knows.

Whats my next move? Take it to a mechanic? I'd really hate to take it to someone just to have them say its just clutch noise...

 

The only other idea my small brain could come up with is, putting the car on a lift and running through some gears with someone under the car trying to pinpoint the noise. Maybe applying a light brake touch would mimic load. A dyno and a mechanic's stethoscope may do the truck too.

But yeah, sounds like it might be mechanic time. If you don't have a mech/buddy that drives an S, or is at least an S2K enthusiast, I suggest trolling your local area forum and start asking around. You really need someone that'll give you the time of day and not some know-it-all service manager.

With some problems, it's worth it to let the problem get bad enough to where it's more evident, but it sounds like you've waited long enough.

 

You know anyone that plays or records music/videos? If so, mount a small condenser mic in the engine bay, preferably not a wide diaphragm due to their fragility. Run the xlr cable to a laptop and record what you hear on a recording program. If you were near me, I have all that stuff.
If you could dually film your driving, and get a recording of the engine bay, then synch the two and make a YouTube vid, that would be the best.

 

Yea I tried getting audio of it but you can't hear it over the background noise of the engine. Its very apparent in person but mics don't want to pick it up. I'll have to check locally then for someone who may a good place to take the car.