The offending pipe ..looks exactly the same as mine ..........
oil leaks out of the joint on the boost pipe (the large stiff plastic pipes) and runs down and drips onto vacuum pipe underneath, it then collects around this pipe where it comes off brake vacuum booster.
this oil lives in the booster pipes and is a feature of most ford turbo diesel engines. WARNING THOUGH.. excessive oil can mean turbo failure ----- most connect 1.8s seem to have this drip though ..nothing to do with turbo failure in most cases.
The boost pipes and intercooler accumulate the oil ........which has to be cleaned out every service by dismantling everything, the older and more worn it gets the more oil ..i suppose.
I don't know if this oil clears itself out if you thrash the thing ....as i only trundle round in mine. never doing over 2500 revs, especially since the 20mph speed limit here in wales
to perform a a boost pipe and intercooler service .
But if you ask me ...myself ...
The following is a a job that should be done on these vans at least every couple of years or 15,000 miles, what ever comes first.
I would be taking all the pipework off including intercooler ..and giving it all a really good clean inside and out ..during the clean you can inspect each piece individually for damage or cracks..or rubber sealing gaskets ..ripped, torn , deformed etc ...
What you will find ------- lots of oily gunge..
I use very strong solution of biological washing powder...sort of 1 cup full to every pint of boiling water ..intercooler has to be taken out...it will probably take 2- 3 pints
Block one end . Rags, towel, plastic bag and elastic band ..pour it in. then let stand for five mins ...shake it ..pour it out and flush with hose.
You could use paraffin , Jizer or petrol ..but that would be far more expensive than cheap Lidl / Aldi or Home Bargains washing powder.
other people with the same problems (not many here) install "catch cans" between the pcv (right hand of cylinder head ) and the boost pipe. which will also lessen the accumulation of gunge in the EGR and inlet manifold which can cause problems after a while.
all the best.mark


