Hi all

im hoping to pick your brains a little with this post .

i have a 2009 s4 avant and it is proving a nightmare of a car to own .
it seems to be loosing coolant and quite a bit of the stuff to from max to min after a 50 mile trip but you can't see the difference in the tank until the engine as cooled .
it has had a pressure test overnight and it only seems to be dropping slightly on this test , I'm told the head gaskets are fine to .
there are no obvious leaks on the car .
i also get a rattle at start up now and again and when the car has been on a long journey the strobing box seems to become clunky and the idle speed rises ?
I also get a burning oil smell when I get out of the car ?
im hoping for some ideas of what maybe causing these problems ? Could they all be connected to 1 issue ? It has been in VAG twice and I'm still no nearer to diagnosing the issues
it isn't over heating and I am getting no codes on a scan .

any help or ideas would be appreciated .

cheers
jay