now i'm thinking this noise could be the camshaft adjuster(9/4)...

https://www.audiforums.com/m_599001/tm.htm

 

As strange as it sounds, remove the serpintine belt and see if the noise goes away. Its becoming common to get really strange noises from the idler pulley on the 4.2L S4 engine.
Anywhere from clicking to a train like whistle noise when reving the motor, all of which are usually engine temp related.

 

-not this.... see next thread....

(in doing some more reseach and listening to the sound onthe initial cold start up i think the problem is comming from the "oil check valves" located right underneath the intake manifold on this v8... in my AESIS there is a note about these valves that says if you here irregular valve noise durring short durations and goes away after extended driving to replace these valves..... i only hear the noise on an initial cold start... i'm thinking these valves are just dirty and on there way to making more noise on short trips? anyone had this problem(maitnance) or serviced an audi with the same oil check valves.... i can try to get a picture up of the valves.....)
thanks for any help!

 

in doing more research last night i came upon some tsb's for the v8 and found there is a TSB on a "rattle or knocking noise" from the camshaft adjuster at cold start(which is exactly what my issue sounds like and only happens at cold starts)... the camshaft adjustment is hydraulically actuated and controlled by the engine oil pressure...

the TSB mentions that replacing the parts may not solve the noise issue... that the camshaft adjusters need to be re-adjusted somehow... but i can not find a preocedure for this....

-anyone seen this/ fixed this/ can find out more info??? any help would be greatly appriciated!!!