*calling audi techiies* engine noise between 3-4k rpm

[hman]

The car is a 2002 ASN code 3.0L petrol v6 quattro A6.

Recently its started making a metallic resonating noise between 3 and 4k rpm - quiet before and quiet after.

Its just had an oil change and un-related (I suppose) new meyer hd complete arm and link set.

Any ideas?

[Tame Technician]

Does it sound like a cam chain, or a heat sheild?

[hman]

Difficult to tell, could be either, comes in at 3k, peaks at 3.5k and susbides to nothing by 4k.


edited to add: its a cam belt on ASN engine, it was changed about 30k ago.

Edited by hman on Sunday 2nd May 00:09

[Tame Technician]

I meant the chains between the two cams in each head.

[hman]

ah, I see!

I took the car to a deserted Industrial area and found the following:-

It happens when the car is stationary engine running (and also happens when driving but more relevant that its engine I suppose)

It is present at all revs, it seems to be acceleration of the engine which causes it

Its present only when accelerating the engine, and louder if you floor the pedal.

Taking it slowly through the rev range it is inaudible.

Its a rattley/grindey sort of noise.

PS.
Its not the same noise as the cam chain tensioner noise that I've heard on youtube, thats a diesel clanking noise.

Thanks for any light you can shed.

Edited by hman on Sunday 2nd May 12:59