[s-cars] New S6 owner / engine noise
gailus at mindspring.com
Fri May 12 09:12:25 EDT 2006
Well, a dual-mass flywheel has a number of springs that couple the torque
between the two flywheel "masses."
The springs sit within annular recesses inside the flywheel:
So perhaps a spring is broken or there is a related problem.
>From: Eric Rechlin <quattro at rechlin.us>
>Sent: May 12, 2006 12:31 AM
>To: s-car-list at audifans.com
>Cc: pkrasusky at ups.com
>Subject: Re: [s-cars] New S6 owner / engine noise
>Paul Krasusky wrote:
>> Eric, I've not been following all this but based on the above, did the
>> car you buy per chance come with an aluminum flywheel? Just a stab in
>> der dark here.
>Thank you for your suggestion.
>As far as I can tell, the flywheel has never been replaced, so I guess it is
>the stock dual-mass flywheel. I have service records going back to while it
>was still under warranty, and there's no sign of the flywheel being replaced.
>It wasn't replaced when the clutch was replaced in July 2003, either.
>I will try to explain the sound better. I spent a good half hour driving back
>and forth today to try to better understand it. It's almost a metallic
>twanging noise, like you might hear when a spring is slid along a surface with
>a groove, causing it to jump (making the twang), then be quiet for a bit, then
>twang again, and so on.
>Imagine a spring inside a cylinder with a cap. One end of the spring is
>secured. The other end, on the side of the cylinder with the cap, is loose.
>There is a groove inside the cap that can catch the end of the spring as it is
>turned. The cap is turned, and the groove catches the spring for a bit as it
>turns, and eventually the spring breaks loose, twanging, causing the spring to
>be caught by the groove again and the whole thing starts over. This sounds
>weird, but I think a contraption like that would make the sound I am hearing.
>I know I have heard the sound before on something completely unrelated to
>cars, but I can't think of where it was.
>I swear I can *feel* the noise if I put my palm on the shift knob, too. It
>could just be my imagination, though.
>Note that the sound only happens when the car is in motion, it is much more
>pronounced when in gear than when coasting, and it is easiest to hear in 5th
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