It might be caused by a lot of things... but we had a similar situation that on a rebuilt engine.

In this case, the crankcase breather tube was collapsed causing that air to be forced out elsewhere. Very little oil, but when atomized got sucked right onto the back of the van. A new section of hose from Go Westy (they were very helpful) solved the problem.

john

> Okay my 88 wolfsburg weekender has black spots all over the back from what I
> have been told is "blow by."