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[Dave]

Hi guys and gals,

My A4 has a strange noise coming from the back. First it sounded like a
humming vibration. In the last two days another noise had appeared which
sounds like buzzing hum.

Both sounds seems to change in pitch with the speed of the vehicle but not
with the rpm (I put it in neutral for a few seconds while rolling at 40 rpm
and the pitch didn't change). I have searched the group for possible
problems but could not find any relevant posts. I have read about rotor
warping and some brake problems and thinking they may be a cause. Has anyone
have any ideas what the noises could be? Also what exactly is the rotor
warping?

There are two Audi dealers where I leave but they both have bad reviews. We
have a good local medium sized private garage. Should I take it to them? We
also have a VW dealership which looks decent.

Thanks for any advice you can give me.

Dave

[Tony]

Sound might be your fuel pump going out.

Doesn't sound like rotor problem but if you feel the wheels to see if they are
hot after driving for a while that should tell you. They should be cool to the
touch or at least not hot. If the brake rotors are dragging they create heat
which will be transfered to the wheels.

Change to the independent (if they have Audi experience and recommended by other
Audi owners) or VW dealer if you do not have warrantee left.

Tony
'91 100q 5spd
'98.5 1.8TQ 5spd

Dave wrote:

[Ronny]

"Dave" <nospam@example.com> wrote in message
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[Ian S]

You don't say how many miles are on the car but I'd guess wheel bearings
too. Since it appears to depend on car speed alone not engine RPM, that
would seem to preclude something like the fuel pump. If it sounds the same
when the brakes are lightly applied, that suggests the brakes are not
involved. Still, that could be easily checked by any competent mechanic.
Does it sound any different when cornering as opposed to going in a straight
line? I doubt too that a CV joint is involved (that problem is usually more
evident on low speed turns) but the CV boot integrity should also be
checked.