Hello,

I recently purchased a 1983 300D, yellow, 173k miles. The car is in very nice shape inside and out. It does need some work mechanically, which is the reason for this post.

I pulled the air cleaner housing to clean underneath and check the condition of the turbocharger, and I found that the oil return tube from the air cleaner was missing. There's a fair amount of oil on the turbocharger, head pipe, and engine mount area. The air cleaner element itself was also filthy, and the housing had a good amount of oil inside. I figured someone had removed/lost the tube, no big deal, easy to replace. However, I began searching for the nipple where the tube outlets into the oil pan, and it is not present. I believe it is usually situated right next to (driver's side of) the turbo drain tube, and it's not there. After researching, I'm beginning to think the motor was swapped for a 1985 edition (I live in California), and the manifolds from the pre-85 were mounted onto the 85 engine. I have no records of the swap, but why would the oil return nipple be absent ? None of the other components from the 85 California engine are present as far as I can tell.

My questions are:
Is there a way to identify the engine by year ?
Were there any 1983 om617 motors that did not have an oil return from the air filter housing ?
How can I properly vent/return the oil from the air filter to the crankcase ?

Thank you for any help/thoughts.

Wallace

It helps if you post up some decent photos of what you're working with .

This isn't a new problem, others have done various fixes, you may need to get creative .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Okay thanks, attaching some photos. I think I have answers to my first two questions as I found what I believe is a two digit year stamp on the front of the motor, pictured down and left of red dot. It says 84, which implies to me the motor was indeed swapped at some point for a California smog compliant motor, but the manifolds and turbo from the original motor were re-mounted. The car is a 1983.

That leaves the third question, which is where and how to route the excess oil leaving the valve cover, passing through the oil separator, and exiting the bottom of the air cleaner housing ?

I've tried to show with the pictures what I'm working with. I also lifted a picture from another thread showing the turbo drain and oil return nipple locations. My motor does not have the breather drain tube nipple.

Any thoughts or solutions much appreciated !

Wallace

Attached Thumbnails

         

O.K., judging by the photos I agree you have an engine swap here, Pic.#2, did you put your finger up behind the turbo drain tube to see if the oil vapor tube nipple is there ? .

NA engines have it and your photo appears to have the turbo oil drain so the vapor tube nipple should be there if out of site .

Once you figure out what you need this should go to - gether fairly easily, I've replaced the O-Rings and damaged vapor tube and am still quite pleased with the lack of oil drips almost 200,000 mile later .

IIRC I had to take off the intake manifold, that's much easier than it looks at first glance .

I hope you have the gone missing engine shocks, failure to have them means you'll soon need motor mounts .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

There are a number of modifications whose objective is to eliminate the stock air filter housing. Some of those involve plumbing the crankcase vent into a catch can. That might be worth a try with your existing air/oil separator. Or you could possibly install a nipple in the turbo drain pipe.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Thanks !

I need to purchase the engine shocks and do the motor mounts as well.

The oil return nipple is indeed absent. I cleaned up that area and stuck my hand in there. I was quite puzzled at first.

What I need seems to be a re-routing of the oil return similar to the 1985 California motor. I believe it just drops the oil back into the intake elbow in front of the turbo, but I do not have an exemplar on hand to work from.

The catch can is always an oily mess, don't go that route .

Adding the oil vapor to the intake might create some blue exhaust smoke .

Some here have done this, I'm hoping they'll chime in soon .

I'm trying to get my mind around what the deal is here with no factory nipple ? .

Maybe get a spare oil return tube and solder a 'Y' connector to it ? . there's no pressure in the oil return tube so that might work , I dunno .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Would it be more of a mess than is currently the case? For sure, it's not the optimum solution, but it would have to be an improvement in the interim.

Not all engines are created equal. The got real unequal in California in the mid-eighties.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Yes of course, I'm not one of those who accepts an oily mess under the hood and an oil soaked driveway .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

If you solder a Y into the turbo return tube don’t forget to add the check valve. There’s one in the bottom of the nipple for the breather vent oil return that keeps crankcase pressure from backing up to the air cleaner.

Thanks for the ideas, guys

Here's what I'm thinking:

What if I plumb a line from the nipple on the bottom of the air cleaner housing and run it into the intake elbow on front of the turbo with a small bulkhead fitting. I think this is the best way to approximate the 1985 setup (See picture). A wye directly into the turbo drain tube also seems like an excellent idea, but more risky given the work involved in removing that piece.

Attached Thumbnails

 

My car also came like this! 1985 (Cali) engine, but with the air filter and intake of a Federal version. When I bought it the crankcase gases went into the air filter housing and then blew out the bottom where the drain was supposed to attach, filling the engine bay with oily gases.

I put a catch can filled with stainless steel wool by the wiper fluid reservoir and plumbed it from the valve cover to the catch can to the top of the air filter housing, and sealed the oil drain in the bottom of the air filter housing. It worked fine in that I no longer had oily gases in my engine bay. It didn't dirty the air filter either.

It was kind of a drag to have to empty the catch can periodically.