the leak is a common problem om the V6
there is a post about the same oil leak you have
http://www.mitsubishiclubaustralia.com/for...opic.php?t=4581found it ...in this forum there are mitsubishi members from ballerat
you turn the cap tight on then back it of a fraction this seals the cap the the rocker
the inlet manifold at the back is a large vent pipe and takes a lot to block it off
so I wouldnt be concerened about that back pipe
to reach the rear rocker cover or do any work / say a new rocker gasket/pipes
the inlet manifold has to be undone