Last time I added oil, I added one quart too many. Since then I always get lots of oil in the air cleaner, which then drains through the holes at the bottom onto other parts. On top of the air cleaner I have the black hose that comes from the camshaft cover, but I also have a cream/semi-clear hose that appears to be coming from the vacuum pump on the front of the engine. I believe the oil is going into the air filter from that creamy-clear hose. (I haven't seen this hose on other diesels, just the black one). Since then I've changed the oil and oil filter, and the air cleaner still fills up with oil, and I have to add oil every couple of days, because it loses it all. What happened? What can I do? It's a 1980 300D non-turbo, 130,000 miles, relatively good condition otherwise. TIA!