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

The old elbows and tube could have heat stress cracks allowing leakage. Replace those old parts as well as the oil filler cap gasket.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

Again, there is not the slightest trace of oil around the oil filler cap... and I have checked very accurately the elbows and breather hose around the elbows and they are dry. The oil leaks out at the very base of the upper elbow juncture... If you referred to the picture from 2005, it is quite messy and you can't really tell. But after cleaning the valve cover and adding those screw clamps a couple of years ago, the leaking is much less and it is quite clear that it comes out from exactly the upper elbow juncture - and also the lower elbow juncture - below the air filter housing - in spite of those screw clamps which are well tightened...

What I still have to understand is, is oil supposed to travel down the breather hose, or just hot gases???

If after this information I've given here you suggest I put in new elbows, I will try that as well... but again they are not cracked... the oil comes right out of the connection between rubber and metal, not from cracked rubber...

Thanks,
Rino

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

That rubber does get heat stressed and hard. Hard rubber does not seal well like soft rubber. Just because you cannot see any cracks does not mean thay are not there.

The oil vapors get in there due to suction from the intake and will condense back to liquid. Hot oil flows better through the slightest openings easier than cold oil. Also check the metal for any imperfections. A slight indentation, and hard rubber ensures a potential leak.

You could also clean the area's really well and use a bit of RTV, but then that will have to be redone every time you take the valve cover off.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

OK, I'm going to get new elbows then... If that really solves the problem, I'm going to kick myself in the ass for not having done it earlier... with the car leaking oil on the garage floor for two years... I really hope you are right about that... it would be a very easy, low-cost solution... (wondering why no one else here suggested it before)

Thank you very much,
Rino

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

As I have already tried to make as clear as possible, the oil does NOT come from either the oil filler cap site or valve cover gasket... It comes specifically from the breather hose connection. There is also oil at the intake manifold below the air filter housing (which travels there through the breather hose) and it makes quite a mess down there...

Again, the problem is oil getting into the breather hose and leaking at the elbow connections, nothing to do with the oil filler cap or the valve cover gasket.

Thanks,
Rino

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

Why do you have oil around your filler cap? It wont be obvious that oil is leaking out of your filler cap. It has happened to me before. I replaced the elbow, still had oil around the elbow. Replaced the filler cap, oil gone for a while. The cap is cheap, gasket even cheaper. Oil comes out the blow hole whether gas or diesel. It just happens. Another possibility is that you have a blow hole that is removable. You could be missing a gasket or it could be loose.

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

By looking at the old picture from 2005, you can't tell where the leak is from... oil in that photo is all over, even near the oil filler cap. But after I cleaned it and installed the screw clamps two years ago, there has been no oil at all anywhere near the filler cap. The oil is very clearly leaking as I said. This is also evidenced by the same exact thing happening at the lower breather hose elbow. However, time will tell if you are right. I will report right back here as soon as I install the new elbows.

Thank you very much,
Rino

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

How much blowby does the engine have?

The gaskets were really designed to be liquid tight, not really air tight, as new engines typically have no blowby.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

You know, I am not sure that it has any blowby at all... as I said earlier in this thread. Later someone insisted that if I get oil out of that juncture, then I MUST HAVE blowby, so I went along with that assumption. However, I have none of the symptoms, to my knowledge, that were earlier in the thread associated with blowby...

Is there a way you can help me diagnose whether I have blowby or not?

Thanks,
Rino

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

I haven't gotten the new breather elbows yet, and I will post an update as soon as I replace them, but I happened to have had the necessity of taking a few pictures of the engine during the past couple of days (for an unreleted reason), so I thought, for the sake of completeness, to take also one of the valve cover to post here.
Compare the new picture to the first one posted in this thread in 2005... The current picture shows that there is absolutely no oil around the filler cap, and just a bit of oil coming out of the breather elbow, which then flows down on the left side of the cover (not visible in the photo). The last time I cleaned the valve cover was two years ago right after installing the screw clamps...

You can also see all the filth covering most of the engine... due to the smoke caused by the leaking oil getting in contact with the hot engine and being burnt back then... BTW, how do I clean the engine (kerosene, commercial products, steam?) I have been post-poning the cleaning all along because someone warned that engine components could be harmed if the cleaning is done incompetently... and so I have been afraid of making a mistake and screwing up something in the process...



Rino

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

You could also check the tube that is attached to the elbow. It could have a small crack or could have been deformed due to overtightening. Mine used to be plastic. I have since replaced it with a stainless tube so that I could tighten it more with the clamp. It is still leaking a bit but not as bad as before.

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

As I pointed out earlier in this thread, the leak is taking place at the connection between rubber and metal (lower part of the breather hose and valve cover intake)... The part where the breather elbow attaches with the hose is totally dry.
Thanks anyway, though.

Rino

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

OK, the new breather hoses haven't gotten here yet, but something significant has taken place. I did an Italian tune-up yesterday (25 miles) and one today (50 miles), really pushing the car to the limit. This is the first time I do something like that since buying the car two years ago. Before the first one, yesterday, I cleaned the area on the cover around the breather hose. Well, there hasn't been a single drop of oil leaking out of that juncture since, in spite of all that hard driving...

So, if the leak were occurring because of a damaged/worn-out elbow, it would make sense that more leaking occurred during this protracted periods of pushing the car to the max, right? Instead, all leaking completely stopped.

By the way, the car performed unbelievably well... I didn't expect it to be capable of such power.

What is this telling me? I would appreciate your feedback on this.

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