What is this Air Filter Do-hickey? Is it Stock?

[olivelawn]

I'm starting to realize I have all kinds of air filter problems on my '82 300 SD Turbo Diesel. After examining pics on the skinnerbox site (http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/Engine/617/09-400.pdf), I can't seem to make out what I've got going on here.

1. First off, is the hose running from the top of the engine supposed to go to the top of the air filter case? Is this what is referred to as the "crankcase breather tube?" The reason I ask is that the pics from the skinnerbox site show it going from the engine to a different area (not the top of the air filter).

2. I opened the air filter case and there is no air filter. Great There is however a good bit of oil inside. I am hoping this is because the rubber elbow leading to the top of the air filter tore and oil managed to work its way into the case. Oil in the air filter is typically a bad sign right?

3. My oil filter case isn't secured. The rubber mounts with screws stemming in each direction seem to have melted and one of the fasteners fell off. I assume this is something I can replace at most auto parts stores?

Here are some pics: