Unknown pipe on 1987 Audi 100 CC?

[JJPACKMAN]

I was wondering whether anyone could tell me what the metal black pipe is that runs from the idle stablisation valve down into the left hand side of the block just before the clutch. I've looked in the haynes manual and it is not in there. It would seem that not all 5 cylinder Audi 100s have it. I need to know what it is because oil seems to be slowly leaking from some kind of gasket under the round dome which joins the pipe with the block/ What is the pipe, what does it do, and how would I replace the seal/ gasket? Thanks

 

[audi5e]

sounds like the crankcase breather pipe. on mine it goes directly to the rubber unit that connects the air distributor to the throttle body.