Oil separator no crankcase hook up 79300sd
 

My sons 1980 300sd had to have upper oil pan replaced. We pulled one from a 1979 300sd after checking that the part numbers on the pans matched. Well today we installed the upper oil pan and found there’s only one inlet to the upper oil pan it is for the turbo oil return line there’s no hook up for the oil caused by blow by to return to the crank case. There’s also the dipstick inlet I don’t have the 1979 300sd air filter housing which on the 1980 model contains an oil separator that then drains down to an inlet in the upper oil pan. Can any one explain to me how the 1979 300sd dealt with the oil mist created by blow buy I doubt they just vented it to the ground. Did they use some sort of baffles in the valve cover to eliminate the need for oil separator and return line to crankcase I am stumped.
Thanks Dave

thought a picture might help
 

the picture from the bottom of the oil pan shows both tubes but my new pan only has a place for the turbo oil to crankcase. The tube I am missing and there never was a hole for. the tube is betweening the blue lines. So where do I hook up the blow by plumming that comes from the valve cover. Does any one know how it was run on a 1979 300sd
Thanks Dave

I don't know how the '79 SD dealt with blowby gasses. I would route the blowby from the valve cover to the plastic u-tube that connects the air filter housing to the turbo. That would probably be the easiest thing to do. FWIW, that's how its done in my current car.

If that is done, liquid oil may be allowed to enter the tube. If that liquid oil contacts the turbo compressor wheel at speed, it will wear down the blades. Spinning around 100k+ rpm, about 1000mph, a little bit can be alot.

routing it to turbo u turn part
 

Yes I would be very concerned about running it in to turbo in take one big droplete could really ruin a turbo spinning at those speeds. I have had no luck finding a 79 300sd at junk yard, Untill I find a better way I guess I will just have to try running it into a catch canister its a rebuilt head on a sound lower end I just hope it will not loose to much oil by not returning itr to crrank case.
dave.

You could try this. Come off of the turbo return connection at the oil pan with a rubber hose, y off of this hose and pick up the return from the separator. I am of the impression that it would be pretty straightforward to replace the hard pipe stuff even with custom stainless steel braided lines. You will want to insure that nothing is touching the turbo housing if you go with oil proof hoses.

I have a 1980 300SD (116)
The blow by gas from the valve cover goes into the U tube after the air cleaner. There is no oil seperator in the air cleaner. This looks stock for the factory. no problem with turbo over 200,000 on engine.