Vague scraping sound when clutch pedal is OUT

[AlphaAssault]

Just a little info:

150xxx miles on body

engine and tranny rebuilt in 2002, about 20k miles on them

new clutch (not sure what kind, but it isnt stock)

So, heres the deal: A few days ago my radiator developed a leak. I drove home after filling the radiator, and it has been sitting outside since. Today, I go out there after FINALLY getting my new rad, and I drop the thing in, no problem (and no tranny noise). I fill it up with coolant, and start the engine to bleed the system. Well, I start the engine and when I go back around to the front I hear an odd scraping sound; very vague, and I can barely hear it over the engine at idle. Well, now im worried as hell. Im trying to figure out where the sound is coming from, and find that its emanating from the bottom of the engine somewhere. Thinking it might be the tranny, I go back and push the clutch pedal in, and the noise stops. I hold it down for a bit, then slowly release and the sound comes back. What does this mean? Do I need to drive it around a bit to mix up the tranny fluid some after sitting for a while? I need to know what this might be before I do anything else.

 

[PieEyedPiper]

Sounds like a bad throw out bearing. When you replaced your clutch what kind did you use? Did the clutch include its own TOB or did you use an OEM TOB?

 

[AlphaAssault]

I dont know. The rebuild was done way before I bought the car, though I have full documentation of the build because it was done by a performance shop. The records I have dont mention anything about a throw out bearing, but it doest list every single part either. However, I want to start with the small things. Because it has been sitting for several days, could stagnant tranny fluid cause this sound? I heard nothing like this last time I drove it. The viscosity of the transmission fluid is one of the few things I can think of that would change as the car sat. Do you think its safe to drive, to see if it goes away and/or see if i notice any difference in performance, etc?

 

[PieEyedPiper]

If it is the TOB, yes, it is safe to drive.
But, be aware, should it fail entirely (should be a while, from my experience) you will likely find yourself stranded unable to get in or out of gear.
The solution is to replace the TOB.

I've seen nothing else to indicate your problem is anything but the TOB, just so we're not jumping to conclusions, is there any other information you would like to add? Perhaps you could tell us a little more about what you think might have caused this. You were, after all, messing with the car when you first noticed the sound. Sometimes it's a coincidence, sometimes it's not.

EDIT: You may find this link helpful. Just something I came across on the front page.
http://www.dsmtuners.com/forums/420...aring-noise-clutch-engaged.html#post151347795

 

[AlphaAssault]

Ok, that scraping went away for about a week, and now its back again. What confuses me is how inconsistent it is. The first time I heard the noise, it was the first time I had driven the car since replacing the radiator. After that first drive, it went away. I heard it again just today. The car was sitting for over a day in cold weather, which may or may not be pertinent. It makes the sound both in neutral and while moving, only when the clutch is out, and you can hear it over the noise of the engine, though only barely. The noise is not effected by the speed of the engine; it will grind for a little over a second, then stop for about a half a second, then start grinding again, and this pattern continues until it goes away. Even with the scraping noise, no hard shifting or grinding while changing gears is noticed; the transmission performs exactly the same, only now its making noise.

If i had to make a complete GUESS about what is happening, i would say some fluid, grease maybe, gets overly thick in the cool weather, combined with sitting a few days (since it only seems to happen after the car sits for a day or two), so something ends up poorly lubed until the tranny heats up. Maybe this is wishful thinking, but I need some ideas. I really hope its not a serious transmission problem.