Help needed to identify nature of oil leak problem

[rino]

I would have done a preliminary search before posting this had I known what keywords to use... I'd appreciate your help in identifying the nature of the problem at hand.

The problem concerns a 1979 240D.

There's oil leaking (it has for the past three months, since I got the car - but lately it's gotten much worse) from what I assume to be the PCV system (I am referring to the pictures from my Haynes Diesel 123 Series manual. However, the configuration in my car differs from what is shown in the manual pictures).

The oil leaks out from the connector on top of the crankcase, right next to the oil filler cap, and the problem apparently is a loose hose connection. What really surprised me, though, is that, upon looking more closely, I noticed that the other end of the hose doesn't connect to anything, but just hangs in the open under the air cleaner box. Why would oil come out of a ventilation hose that, as far as my understanding goes, is supposed to convey just burnt gases? Besides, the other hose, the one attached to the connector on top of the air cleaner (which is identified in my manual as the PCV ventilation hose and is shown connecting to the connector next to the oil filler cap) attaches somewhere else in my car (instead of going to the connector next to the oil filler cap, as shown in the Haynes manual). I find it very confusing and am trying to understand which is which.

I'm planning to lift the air cleaner box in order to see if there is a connector hidden under it where the loose hose should connect... Please let me know what you think.

Rino