I would have done a preliminary search before posting this had I known what keywords to use... I'd appreciate your help in identifying the nature of the problem at hand.

The problem concerns a 1979 240D.

There's oil leaking (it has for the past three months, since I got the car - but lately it's gotten much worse) from what I assume to be the PCV system (I am referring to the pictures from my Haynes Diesel 123 Series manual. However, the configuration in my car differs from what is shown in the manual pictures).

The oil leaks out from the connector on top of the crankcase, right next to the oil filler cap, and the problem apparently is a loose hose connection. What really surprised me, though, is that, upon looking more closely, I noticed that the other end of the hose doesn't connect to anything, but just hangs in the open under the air cleaner box. Why would oil come out of a ventilation hose that, as far as my understanding goes, is supposed to convey just burnt gases? Besides, the other hose, the one attached to the connector on top of the air cleaner (which is identified in my manual as the PCV ventilation hose and is shown connecting to the connector next to the oil filler cap) attaches somewhere else in my car (instead of going to the connector next to the oil filler cap, as shown in the Haynes manual). I find it very confusing and am trying to understand which is which.

I'm planning to lift the air cleaner box in order to see if there is a connector hidden under it where the loose hose should connect... Please let me know what you think.

Rino

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

Here's a picture of the connector that leaks oil.
It's the one just above the oil filler cap.

Please respond and let me know what you think.

Attached Thumbnails

 

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

Under the valve cover you have an oil line running along the cam.. it is squirting oil onto the cam lobes... so in all that air space under the valve cover you have oil being flung about..
In the old days valve covers had ' breathers' on them which was just an opening to the air but with something like brass wool in it... which would accumulate much of the oil and let it drip back into the engine...
Then Clean Air happened and they started taking those fumes and re burning them ... so this tube just goes to the air filter so those oil laden fumes can be sucked back through the engine and exhausted at the tailpipe...
You need to fix that junction between the rubber line and the valve cover.
It does not look to be original... looks to have a hose clamp on it... I think originals are available..
Also renew your gasket on your oil filler hole cover... and when you open that be sure to never turn it upside down... as oil will run into the top and then onto the valve cover when you put it back on...

Now I know why I always had oil around my filler hole after an oil change. Thanks for the tip Leatherman I learned something new today.

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I hang out with Boneheaddoctor at Schuman Automotive OBK#5
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Take off your air cleaner and look for the port where it is supposed to connect to the intake manifold.

If this is disconnected and not properly blocked off..your engine is sucking dirt strewn air in that hole (bypassing the air cleaner).

The system on that 240D is simple and only has 2 rubber elbows and a hose. It just blows the air from the valve cover over to the intake and burns it up. The later 5-6 cylinder models are much more complex as they capture oil/oil vapors and return the liquid to the oil pan while offing the air into the intake. (Ideally )

Thanks for your input.
Actually, I fixed the problem this morning by securing both ends of the ventilation hose to their relative ports by means of two large screw clamps.
And yes, as you say, the hose was disconnected from the lower intake port.
My guess is, it had been for over three months, during which I have put over a thousand miles on my car... I'm lucky the car has been running flawlessly.
However, the problem is now taken care of, as there is no more oil/smoke in sight.

Also, thank you, leathermang, for the info.

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

What kind of baffle etc. is on the inside of the valve cover? Can it fall out?

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Dropout

1978 240D work in progress

Very unlikely. It's pretty much a part of the valve cover (I think it is in there and then peened to hold...not sure.)

If you think it might be fallen loose...take off the hose where it hooks to the valve cover and poke a screwdriver in the hole. If you get quick resistance then the baffle is there. If you don't, either you don't have a baffle or its loose (should be able to hear it hit your screwdriver).

if it was loose totally i would think it will rattle against the cam. a hell of a racket and not to be tolerated as it would damage the cam.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

This is part of my recently revived take-good-care-of-your-MB project...

This oil leak has been going on since I bought the 240D two years ago (in a much lesser fashion since I installed two screw clamps on both ends where the breather hose attaches to its ports.) Please see photo depicting the problem in one of the previous posts in this thread.

This is luckily the ONLY oil leak in my engine... The oil comes out, notwithstanding the large screw clamp, from the upper breather hose connection (see photo) and travels all the way down along the engine walls, and then drips on the pavement of my garage. What I don't understand and perhaps someone here might be able to explain, is: why is oil coming out of the breather hose opening (at the upper elbow) when just air/hot gases is supposed to travel from there to the lower intake port at the air filter to be then burned in the engine? I keep my engine oil level never above midway between the upper and lower marks on the dipstick, and often keep it lower than that, just because of THIS problem (I found out that keeping more oil in the engine worsens this issue - more oil gets expelled from the breather hose upper elbow connection...)

What do you think this means and how do you think it can be fixed?

Rino

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

Hi Rino.

Just read this.

blow-by questions...

Louis

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Not always the smartest but certainly not dumb?

Hi Louis, I have just read that thread attentively, but here the issue seems to be quite a different one. My engine starts very readily when cold (it takes about 1 second for the starter to have it running...) and I don't have the blow-by noise issues or smoke and pressure coming out of the oil filler cap described in that thread.
The problem for me is the engine OIL ITSELF coming out of the breather hose junctures - and not the oil cap! When I replaced the air filter yesterday, I removed the whole thing (air filter housing) and inspected underneath it, the lower breather hose juncture (where I had placed a screw clamp also in 2005) and the manifold opening...
There was also oil (filthy, greasy) there too and all around it (as well as a bit of it on the bottom part of the old air filter where it sits against its housing), which I thoroughly cleaned out before reassembling...

Did I miss something in that thread, or what it describes is an altogether different issue?

Thanks,
Rino

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

It just occurred to me... could it be that the breather elbow/hose I have on is not the proper type for my vehicle and that's why the oil travels along with the gases through it? I thought perhaps the proper type of hose would have something to prevent the oil from getting in, such as brass wool in it, or some other type of filtering... Can you just give me some input on this, guys?

Any ideas? Anyone?

Rino

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

Is it possible that doing a valve clearance adjustment will take care of engine blowby and, if that were the cause for the oil getting into the breather hose, fix or at least reduce that problem, in your opinion?

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1979 240D, W123, 105K miles, stick, white w/ tan interior.

Replace your oil filler cap or gasket as suggested earlier. Oil could be coming from there. Since you already clamped that elbow real good, oil could just be blowing to the elbow from the cap.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles