If I'm interpreting my shop manual correctly, the green tube here is attached to a Positive Crankcase Ventilation Regulator Valve: This valve and I have something in common in that, before today, neither of us knew each others' names! As you can probably see in the photo, I have what appears to be fresh oil leakage on the side of my 144 here. When I wipe it off then the fresh shiny stuff reappears during my next drive. This little elbow joint (valve?) with the green tube attached (right between my water pump and distributor cap) is positioned just north of where the most prominent area of fresh leakage seems to be recurring. I looked to the shop manual to find out what this thing is, does, and what on earth flows through it. I'd presumed either oil or coolant until the shop manual indicated "air." Does air flowing through the crankcase carry enough oil residual to cause oil leakage from a connection like this? Is this normal? I've already replaced my valve cover gasket, including reflattening the valve cover perimeter where it was previously overtightened. I think I've got a decent seal there now. At this point I'm not seeing any significant leakage north of this regulator valve connection, but it seems weird that an air flow valve should be leaking oil. But is that what's actually happening here? Am I missing something?