Cool. But how large a diesel are we talking here? I could see that being the case in ship sized diesels but a smaller diesel could eaily vent its positive pressure through a breather.
Every car sized diesel I have ever come across has a small amount of blow-by. When was the last time you dropped the oil on a diesel to have it come out honey coloured? Not hard to understand considering comp ratios of like 20:1!
But hey, could there be an exception? At over 200k mi?

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi