is it right to have oil in the air pipe work to and from intercooler on my audi a4 1.9 tdi i noticed this after having to replace a split pipe to at he bottom of the intercooler but have traced it through most of the pipe work
right - no.
normal - yes!
this is due to the oil breather from the cam cover which feeds into the intake pipe.
ideally it should all be cleaned out...
you can avoid it happening again by fitting either a catch tank, or an oil breather filter (straight to the air) - although this method can cause the oily deposits to be on the outside of the engine, rather than the inside. Looks worse - drives better!