Lots of Oil in Air Filter 81 300D - PeachParts Mercedes-Benz Forum

biopete · #1 12-04-2005, 11:16 AM

HI all. I've searched and browsed and found references to this problem and no solutions. I have a lot of oil in the air filter of my 81 300D . It is so much that I need to change the air filter every month.

I really do not know where it is coming from . The Camshaft cover vent tube goes to the air filter PCV valve sytem. I checked that oil could flow all the way down to the engine oil pan by disconnecting the tube underneath at the pan and pouring oil through the top. It flows fine.

So now what ? I notice from manual that the PCV valve has an oil separator in it. I wonder if that is bad?

I also read here about EGR valve causing oil to get in. I have know idea how that would hapen as that vents in the intake manifold, downstream of the air filter.

Thanks in advance for any help.

jcd · #2 12-04-2005, 07:11 PM

If it's anything like my 1977 300D, I would expect a torn vacuum diaphram.

Do you have a hose running from the vacuum pump to the top of the air cleaner? If so, that is probably it.

JCD

boneheaddoctor · #3 12-04-2005, 07:12 PM

Ummm the OM617 has no PCV valve in it....you are probibly reffering to the oil seperator....check and see that the seals to it are tight and not split.

The EGR also contats NO oil....it lets soot into the Intake...but no oil.

biopete · #4 12-04-2005, 08:10 PM

Quote:

Originally Posted by boneheaddoctor

Ummm the OM617 has no PCV valve in it....you are probibly reffering to the oil seperator....check and see that the seals to it are tight and not split.

The EGY also contats NO oil....it lets soot into the Intake...but no oil.

Thanks. There is a PCV system. No valve per say. Just habit to add "valve" after PCV I guess. The oil separator is part of this system. The system's function is to "circulate fresh air through the crankcase to pick up blow by gasses which are then routed to the air cleaner " and thus reducing hydrocarbon emmissions. [Haynes Diesel 123]

I am glad to hear no oil gets in the Exhaust system. I am guessing than that I have a BADDD oil separator. Because the intake manifold is caked with about 1/8 inch of oil sludge. The seals look pretty good.

Has anyone ever had to buy a new air cleaner/PCV assembly to solve this?

biopete · #5 12-04-2005, 08:17 PM

Quote:

Originally Posted by jcd

If it's anything like my 1977 300D, I would expect a torn vacuum diaphram.

Do you have a hose running from the vacuum pump to the top of the air cleaner? If so, that is probably it.

JCD

Thanks. This one does not but I think my 1980 300CD does. On it the Crankcase Vent runs directly to the air cleaner. On the 81 300D I am curious if a part failure is causing the oil in air cleaner or if it is extremely excessive blowby or both? I patrolled the system for leaks and did see a little around the seams of oil separator. It did not seem excessive. It seems the sytems is designed to separate the oil from the air so most of the oil drops back into crankcase ?

Thanks

87tdwagen · #6 12-04-2005, 08:53 PM

I just did this on my 603, similar issues. The separator can is a mall water/air separator commonly available for air tools and compressors. The catch can is clear and can be conveniently tapped into the breather hose. This will separate your oil vapor and minimize the amount that makes it to the air cleaner or intake.

During Turkey day I did 2 x 1000 mile trips mostly at 80mph and noticed that the catch can almost filled up on each 1000 mile leg of highway speed which cause more blowby. That amount equaled 1/4 cup or 30 ml, not much. 1000 miles of mixed driving produces less more in the range of 22ml.

Best of all you can add an oil return line to the sump, or just empty it right back into the engine. No net losses as compared to just burning it through combustion.

Cheers

biopete · #7 12-04-2005, 10:31 PM

Quote:

Originally Posted by 87tdwagen

I just did this on my 603, similar issues. The separator can is a mall water/air separator commonly available for air tools and compressors. The catch can is clear and can be conveniently tapped into the breather hose. This will separate your oil vapor and minimize the amount that makes it to the air cleaner or intake.

During Turkey day I did 2 x 1000 mile trips mostly at 80mph and noticed that the catch can almost filled up on each 1000 mile leg of highway speed which cause more blowby. That amount equaled 1/4 cup or 30 ml, not much. 1000 miles of mixed driving produces less more in the range of 22ml.

Best of all you can add an oil return line to the sump, or just empty it right back into the engine. No net losses as compared to just burning it through combustion.

Cheers

Alright. Sounds good 87TDwagen. So what you are saying is put an inline oil separator between the air filter and Valve cover vent to replace the broken one built into the air filter? It will do a better job and at a better price than a new one from MB? And it is a Mall (brand ? ) water air separator ? And tap right into the oil return line (crankcase vent line) that your built in oil separator attaches to?

Do i understand you? Can you post a photo your mod ?

Much thanks,

Boardmonger · #8 12-04-2005, 10:35 PM

Well I seem to have the same exact problem on my 81 300d euro. I believe it doesn't have an oil seperator but my air filter is all choked up with oil and my intake is clogged. It runs from anywhere between 1/8 to nearly an inch thick oily build-up. I know this isn't normal but I don't know what to do to stop the oil from falling into my air filter and intake.

biopete · #9 12-06-2005, 09:01 AM

boardmonger, does your air cleaner have an outlet on the bottom that slides in a pipe that goes down to the oil pan? Do you have a weird cone shaped contraption in the camshaft cover vent tube attaches too ultimately? If so, in that contraption is probably the oil separator. You could also check the online shop manual (cant recall link) and see if you have one. I'm guessing you do because I think that cars that do not have the vent bypassing the air cleaner and going straight to the manifold like on my 1980 300CD. In that case , I see know way oil could get in the air cleaner at all.

Hope we can solve this soon.

Boardmonger · #10 12-06-2005, 06:14 PM

I am not really sure. I will take some pictures when I get home from work and maybe you can tell what is going on. I thought I read somewhere that the euro spec cars didn't have a seperator so I was assuming my car didn't have one. I am not looking forward to cleaning out my intake.