A fellow S2000 owner I know got T-Boned a few weeks ago--aside from the morons at the auto body shop putting the S2000 side badge on reversed (2000 S), his car now makes a thumping/purring noise under a few conditions, but it can always be triggered when the clutch is let out without giving the car gas. The noise comes from the center of the car just fore of the footwell and disappears when the revs go up. I was thinking engine/transmission mount, but an inspection didn't reveal anything out of the ordinary. Are there any particular things that break in an impact that might reveal the cause?

 

This is not enough information. Please expand.
Are you saying the tranny is in neutral? Because if it isn't and he's not giving gas, then when he lets out the clutch the engine should stall.

 

1st gear--let the clutch out sllllooowwwllyy and just as the car starts to pull forward, the revs drop and you hear the clunk clunk clunk (3 or 4 clunks a second?)....it sounds exactly like an unbalanced driveshagt spinning around and nailing something, but unlike that, the sound goes away when the revs go up.

 

my S2k does the same thing if I do what you describe above. in fact, the entire car shakes. if that's all it is, IMO it may just be normal vibration from the engine almost stalling.

 

They call that "lugging" the engine.

 

I'm sure if you tried this with your own car, it'll do the same thing.

 

It happens at other times, too--at idle occassionally, when revs go up, when revs go down, but it's inconsistent--the one time it can always be provoked is as I described above. It's not the typical sound the S2000 makes and only happened after the accident. I was thinking engine or transmission mount. Is there any way to easily check the mounts without pulling the engine?

 

If its an engine mount...woudn't the car shake and vibrate at idle?

 

The engine mounts are fluid filled. Check to see if there's any leaks. As for the tranny mount, I believe it is a solid rubber mount. Check to see if it's cracked or shifted. I suppose that the crash could have damaged one of the CV like joints at either end of the propshaft.

 

Thanks, guys.