Audi A6Avant..knocking noise from under the dash

[Sprogg]

When travelling at slow speed I get a noticeable knocking(not rattling) noise under the dash.It was MOT,d very recently.I have had seven technicians(two master technicians) look at it and although they hear the noise they can not locate.Bearing,shocks,links etc all sound.
Does anyone know of a steering rack issue.It is worse when cold in the morning.Please help.
sprogg

[adani24]

Need a bit more info really. Could you try recording the noise and posting the video on youtube?

Is the noise apparent when the when turning, accelerating, or braking, or even both!

Could it be a simple undertray not secured properly?

[Sprogg]

Hi, thanks for the reply.It is at slow speed mainly that it is most noticeable, , not whilst turning or accelerating.On a flat nice road you would never notice it and the car drives well.Its not the under tray or the suspension or the links or the bearings they are all tight and have been well tested.With a young family and I do a lot of miles so far I've been told " wait till it gets worse" and that advice cost me £75 from a master technician.Its worse first think in the morning when the car is cold.
i don't mind paying to get it diagnosed but so far I have paid and got no where.

[adani24]

Not having experienced the noise that you are hearing, I too would let it get worse whilst monitoring mpg and tyre wear.
Have you topped up the power steering fluid?

Could it be the flap recirc motor for the heating system?
Which side of the car is the noise coming from?

[Sprogg]

Adani
thank you for this..,I know t he noise that you refer to from the heating system.Its not that.Tyre wear mpg good.What is noticeable is that when the car is cold...first thing in the morning it is much worse and almost disappears as the car warms up.But it is still a worrying noise...not a rattle.I wonder if there is a rubber mount either in the steering column or suspension that softens as it gets warmer? Who knows.Thanks again for your suggestions.Audi want £170 plus vat just to look at it!Sprogg