I am no expert on diesel engines but I would note the following:-
1) Removing the ERG is probably not legal and in any event who wants to create more nitrous oxides
2) The oily sludge is engine oil not diesel- This could only come from the turbo (in which case you would probably have a very high oil ...

I have a 1998 Bongo Diesel. Attached to the front of the driver's side rail for the middle seat is a key or tool. Its clearly factor fitted but i've no idea what it is for. I would like to show you a picture but I've no idea how to paste one into this posting.