little puddles of oil showing up in my air cleaner and wetting the filter. Should I use air pressure and blast the return tube to sump to check for blockages or pour oil down tube and see if drains quickly? Is it worthwhile to clean strainer/filter in air cleaner by bending up metal tabs and washing with solvent -this car at 356,000 miles has some pretty good blowby but has always had regular maintenance, etc. I am replacing valve stem seals today and will chase oil passages at the same time as I am curious to see if there are any blockages. This car runs great, fires immediately and did so with very poor valve clearances -

I just did this on my 85.

I cleaned the seperator out really well. Bent the tabs up and cleaned all that up. and put the lid back on with some RTV around the edge. I also replaced the O-rings on the drain: One where the air cleaner meets the pipe and one where the pipe meets the oil pan.

I did not have anything inside the seperator itself though. Is there supposed to be something in there?

One thing I did read after the fact is that there is a check valve near the oil pan, I did not check that and will next time I have everything apart.

I still get leaks around the "nipple" on the valve cover that goes to the air/oil seperator. I really wish I could fix that. I have some blowby as well, but it is not bad at all. I have seen much worse.

__________________
----Adam

1985 300SD 322,000

That return tube is about 1/2" in diameter... what could be blocked there?

Are there any "deformities" to the air filter housing?

Where does the oil tend to pool? Pics?

__________________

'82 300D (project)
'46 Willys (project)
"Nothing seems to be the way it should in this garage." -jt20
"Smarter than an engine, dumber than a hoodlatch..." -jt20
"Start jumping up and down to smoosh down those engine mounts" -DeliveryValve
"no" -kerry
"At this rate, you may have it done by winter" -layback40

bottom of air cleaner, noticed that element was oil soaked here and there, sorry no pics. I feel the same about return tube, no sure what could be blocked there as diameter is large but I have read to check this in other threads -perhaps check valve and oil migrating upward?

theoretically, there shouldn't be pressure in the pan, so oil should not be migrating upward...

__________________

'82 300D (project)
'46 Willys (project)
"Nothing seems to be the way it should in this garage." -jt20
"Smarter than an engine, dumber than a hoodlatch..." -jt20
"Start jumping up and down to smoosh down those engine mounts" -DeliveryValve
"no" -kerry
"At this rate, you may have it done by winter" -layback40

ok, you have a good start on the fix for this. yes, gently bend the tabs on the collector and remove the lid. clean well with brake spray/rag/brush, and dry. apply some ultra black RTV on the lid and reinstall. the siphon hose that's on the lid, needs to be cleaned and put back and be sure and use some ULTRA black RTV on it too. then on the elbow on the valve cover do the same, clean it well on both ends, and coat the male parts VC/Plastic tubes of the joints with UB RTV. let it cure overnight. VOILA! no more oil on the valve cover, and no more oil on the air filter!

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Failing vacuum pump, allowing engine oil to be pushed into the air cleaner. Split diaphram on my older vacuum pump was the culprit.

Gerry
'77 300D, 408kmi

I'm having similar issues. Can you describe the path from the vac pump to the air box? I'm having trouble envisioning 1) why oil is in the vac pump in the first place, and 2) How it migrates from there into the air cleaner.

Thanks

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

this would be true if you have an older n/a 617, however, the OP has stated there is an oil separator in the air cleaner, that means he is driving a turbo 617, and the turbo's do not have a vacuum pump that dumps externally.
but this comment is valid for the thread as the OP did not state which car or what year vehicle he has!

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

That concept is n/a for the newer piston-type vacuum pump.

is your problem in the SDL or the 240?
the 240 of yours has a tube from the vacuum pump into the lid of the air cleaner, and if the seals fail on the vacuum pump it can pump motor oil into the air cleaner through this tube.
the sdl vacuum pump is internally vented, so if the seals fail on it, oil would just circulate internally into the motor again.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

It's actually the 300SD that I posted about in my "turbo seals" thread a week ago...don't know what I titled that thread now. there was good advice in there that I can't act on until I go home for another weekend.

I burned through 5-6 quarts of oil (blue smoke lingering around curves going up the mountain) in less than 250 miles on the first big trip I took in the SD and it's got too few miles for bottom end wear (rings) to even be a serious factor. My thought was turbo seals, but my dad did Brian's "3000 RPM with no load should produce the same smoke as you were seeing on the road" test, and it didn't smoke that much. We're still checking stuff. The air filter area is very oily, and so our next place of diagnosis is to see if the separator is working okay. If the separator's check valve were plugged up or something else is wrong with it, then perhaps the oil is burning because it can't drain back. But anyway -- let's not derail the OP's thread any further. We can move this to my thread here 300SD Oil Burning (Turbo Seals? Rings? Valve stems?)

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

I did all of this plus more. I filled the return line with oil to see how fast it drained back to the block - very slow. I filled it again and applied a little compressed air just using my fist to seal the air nozzle to the oil filled return tube. Didn't take much but suddenly started flowing faster. I think maybe I had soot at the check valve. Once it cleared, I added a full quart this way to flush as well as possible. I would not flush with anything but oil unless I had the pan off. I now check it every oil change by adding about an ounce of new oil to the oil seperator intake at the top of the aircleaner. That flows down the return line. Be careful not to add to much or it will overflow into the intake and lock up the cylinders. I did that once and had to wait two days for the oil to drain down past the rings before it would start. Then a lot of sputtering and smoke until it burned or blew out.

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

... it's not supposed to flow oil fast. the checkvalve resists oil flow. only drops at a time should collect in the can, so oil should trickle into the block.
I don't think I'd apply pressure to the checkvalve... I'd hate to damage it and have oil suck into the intake...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

eeek! I could be wrong but some time ago -if memory serves I may have blown compressed air into the drain pipe -wonder if you can damage a check valve this way - I suppose if I poured oil into the drain pipe and it flowed fast, this would suggest a check valve that is potentially stuck open?