Sealing a Porsche fan on a type4

[giraffeinbath]

I have a type 4 with a Porsche fan conversion which I've not had running yet as it'sjust been stashed but now I'm building it back up.

I was thinking should there be some sort of seal under the Porsche fan where it sits on the (machined) case?

As I recall the PO had a problem with everything being covered in oil vapour in the engine bay, could this have been a possible outlet?