Strange noise.... Help!

[rootytooty]

Hi,

I hope someone here can help or has had a similar experience with their RS6.

I have a 2004 C5, my second RS6, that has developed a strange noise. I'd describe it as a droning, fast whirr. Not a whine. It comes on after around 35mph, then gets lost in the engine noise, but at speed i can just about make it out, still droning/whirring. Then when i slow down it's there again from about 35mph to 20mph then it disappears.

Could it be the early sign of a shot wheel bearing? Or am i looking at a more serious transmission issue?

I realise that the info i've given is pretty vague but i'm hoping someone else might have been through the same..

Cheers,

James

[Daveperc]

Ok - first of all FON!

Next a question - does the droning vary with road speed or with engine revs? And can you give a clue where in the car it is coming from??

Dave

[rootytooty]

Glad that's over with

In answer to the questions- It seems to vary with road speed, not so much with revs. And I've absolutely no clue where it's coming from. I've listened, but can't pinpoint whether it might be from the front middle or one of the four corners. It doesn't feel/sound like a bearing but as I've never had one go on one of these I don't know..

I've had it up on stands, all the wheels feel fine. Tyres are good, 5-6mm of tread all round, Pilot Sports.

I'd rather diagnose myself than run it somewhere

[ahoooga]

El Knobbly maybe ? viewtopic.php?f=2&t=89329

[rootytooty]

Could be.. I'll have a look later on tonight. Cheers for the replies so far

[rootytooty]

Tyres are all fine, no uneven wear

[chunky79]

It's the side wall you need to look at, not the part that makes contact with the floor .

[Shoppinit]

Probably either drive shaft center bearing, inner CV joint or diff bearing. IF the latter then sod's law dictates it'll be on the difficult side.

Could be wheel bearing.

Might be deformed tyres. Swap fronts and rears to see if that modifies the sound at all.

[rootytooty]

Sidewalls are fine.

Cheers for the replies. Went out for a drive earlier, it's a lot less subtle now- more like a whirry grind and throb than before. Starts around 25 mph and picks up with speed, still there when I coast to a stop in neutral.

Is there a way of checking the bits listed above?

[Shoppinit]

Hope your transfer box isn't running dry. Any sign of oil leaks under the car?

[Mɐʇʇ]

Does it change when you go round a corner?

[rootytooty]

Had the car on all fours the other day, no signs of any fluid anywhere.

Tried taking some long sweeping bends, left and right, couldn't really tell wether the noise got better or not..

Pah

[Shoppinit]

Get it in the air and check for play in the driveshafts.

[rootytooty]

Get it in the air and check for play in the driveshafts.

I think i'll be in trouble if i do that now. Can i do it on Saturday?

[Mɐʇʇ]

Right. In my experience (which I'll admit is both flawed and limited), if it's wheel bearings the noise changes volume as you increase & decrease the load on the bearing. So less likely to be a wheel bearing. And driveshafts are usually a click,especially on full lock, rather than a drone.
And it does it even if you click it into neutral? If diff related, I'd expect it to go when in neutral (hence me wondering if a wheel bearing) when the load is off.

Tried taking some long sweeping bends, left and right, couldn't really tell wether the noise got better or not..