The Ringleader

Hi there. New guy trying his luck here...

The ride: Audi S8, 2000.
The noise: From about 30 kph and increasing speed I have this sound which reminds of exaggerated tyre noise. Kind of a cyclical tone.

Itīs pretty much the same regardless of:
- turning
- in or out of gear
- set of wheels (have tried 3 sets)
- wheter accelerating or not
- speed (just gets a little louder with increasing speed)

I can pretty much locate the noise coming from front/center. Also Iīm pretty sure that I can feel some delicate vibrations from the floor when the noise is at its loudest.

Pretty please, with sugar on top, help me with input!!!

Have a nice one! / Josef

Bruce M

Does it sound like RF noise? Check alternator, belt tensioner too.

The Ringleader

Okey, but shouldnīt I hear the noise while standing still, idling, if it were a belt causing it? The alternator likewise?

Sorry about my ignorance, but what do you mean with RF? Now I feel like "Hello, my name is Inga, Iīm from sweden...."

jfrahm

Wheel bearing maybe. Mine went at 90-some K miles. Jack up the front and see if the wheels are loose. Use a decent jack, not the widowmaker in the trunk.

-Joel.

The Ringleader

Yepp, thought of that to. But I pretty much excluded that since the noise dontīt change while turning... Am I thinking wrong here???

Kneale Brownson

Brake pad rubbing on disk? Check wheel temperatures after some brisk driving. Put the back of your hand NEAR each wheel. Don't touch. A hot wheel from a dragging brake pad can burn you.

jfrahm

Hard to say, depends on how tight a turn I guess. I'm not sure if the noise is RPM dependent or not from your description. You say it gets louder with speed? But the same pitch? Can you record it and put it on youtube or attach a sound file?

Check your electric fan for proper operation too, as a longshot. If something is rubbing on it and the airflow gets it going that might make a noise like that.

I would also try coasting in neutral and seeing if you can change the noise by revvign the engine, hitting the brakes lightly, etc.

-Joel.

RJPUK

Let me know if you find it. I have an identical single pitch whine on my 98 S8 that I have been unable to track down. It has not changed in a year, although day to day it can be louder or almost inaudible. Only on motion, doesn't change with revs, steering position, gearbox in neutral or drive, braking, a/c, fan or indeed anything. Sounds like tyre noise, but purer tone and seems higher up (although difficult to tell). Over new, sound absorbing tarmac it is noticeably reduced, so it is being generated outside the passenger compartment. It definitely takes a few minutes of driving before it appears. I thought (from partially tarmaced road repairs) that it was from one side of the vehicle, but have not really proven that. As it has not changed over a year, I have grown used to it and just ignore it, (also if I sit back a bit it reduces, so the resonance transmission is slightly odd) but it would be nice to know what it was. My best guess is a drive shaft bearing, but I would have expected a change in pitch with speed. I hope you have more success than me in tracking it down. The good news is that from my experience it appears completely harmless.

jfrahm

Hmm, maybe the EGR air pump in the airbox? That might run when stopped as well though.

Kneale Brownson

Have you torqued the lug bolts?