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i keep finding oil in the intake tube in my 1996 mercedes c220, this model doest carry the crank case valve or pcv, how can i fix this?
the little hose that goes from the valve cover to the intake tube is new, as well last the maf sensor. oil and filter are new as well
What can i do to fix this problem?
please take a look at this 21 second video
IF this is the case and you have oil in your MAF intake line, the oil (film - looks like alot) has to be coming in from somewhere.
Look for another hose/ line maybe 1/4" or slightly larger that is going into your airbox.
Open up you airbox and check the filter housing to see if you have any oil saturation on the air filter or in the airbox at the bottom.
There should be possibly an inlet/opening in the airbox with a hose that is attached to it on the outside of the airbox. If so, where is that hose going into the airbox coming from?
Unless its inside the valve cover, there is no oil separator visible at all under the hood.
take a look a this picture please. notice that next to the oil lid is a metal tube, thats where the hose connected to the intake tube goes.
i don't want to open the valve cover to take a look ( without being sure whats the problem ) because then i will have to replace the gasket
Last edited by magodeoz73; 11-12-2018 at 06:24 PM.
Reason: add a photo
Thanks for your answer, i have looked into the air box and its clean, no oily filter or oil residue in the air box, most of the intake tube is clean as well. i still think the oil is coming from the metal outlet in the valve cover, please take a look a this video
it goes to the intake tube right before the throttle body
just where the oil is in the first video
Show us where on the intake tube right before the throttle with a photo please.
Im guessing this is for return 'oil fumes/vapour' to go back into the system to burn off (kind of like a closed system for reusing/burning of the oil) - like what we have here with the oil separator valve modded to vent into the atmosphere and not back into the system (thru the airbox and intake line).
If it going back into the line just before the MAF or after it, then this is your issue.
If you have inspection regulations where you are, this is to maintain any excess oil fumes to be expelled into the environment.
You could replace this short hose connector with longer, say a longer 3/4" hose line into the atmosphere (redirect the hose down into the opening in the engine compartment below.)
I believe that hose is for the oil separator, which the Haynes Manual says, for the C220, is in the top of the cylinder head. It should be under the valve cover. This vents the blow-by gasses from mid-part to full engine load, but it usually doesn't go bad unless the hose plugs up. Haynes also shows a restrictor located right near the intake on the cylinder head (under the intake manifold), with a tube running from the crankcase to the restrictor valve. The restrictor vents blow-by gasses from idle to mid-part engine load. Restrictors just have a small fixed hole to regulate the amount of blow-by gasses going into the engine intake. Over time this small hole can be become plugged. You can see if the restrictor is clear by carefully checking for engine vacuum at the crankcase side of the restrictor.
I believe that hose is for the oil separator, which the Haynes Manual says, for the C220, is in the top of the cylinder head. It should be under the valve cover. This vents the blow-by gasses from mid-part to full engine load, but it usually doesn't go bad unless the hose plugs up. Haynes also shows a restrictor located right near the intake on the cylinder head (under the intake manifold), with a tube running from the crankcase to the restrictor valve. The restrictor vents blow-by gasses from idle to mid-part engine load. Restrictors just have a small fixed hole to regulate the amount of blow-by gasses going into the engine intake. Over time this small hole can be become plugged. You can see if the restrictor is clear by carefully checking for engine vacuum at the crankcase side of the restrictor.
Learned something new. I did not know it would be under the valve cover, go figure.
magodeoz73,
With this info, what I said in the above post would then make some sense.
As a suggestion only, replace that short stubby line with a much longer 3/4" hose line and direct it out thru an opening between the engine and the engine bay to the bottom of the engine compartment where the fumes/ vapour can vent out into the atmosphere and away. (Note: I am not condoning venting the oil fumes into the atmosphere, if your countries laws say this closed system is a law and you have regulatory inspections in your country.)
No more oil vapour into your intake line. This is very similar solution to the Subby oil separator mod on those c230Ks with the oil vapour issue into the intake line and contaminating the MAF, etc.
Learned something new. I did not know it would be under the valve cover, go figure.
magodeoz73,
With this info, what I said in the above post would then make some sense.
As a suggestion only, replace that short stubby line with a much longer 3/4" hose line and direct it out thru an opening between the engine and the engine bay to the bottom of the engine compartment where the fumes/ vapour can vent out into the atmosphere and away. (Note: I am not condoning venting the oil fumes into the atmosphere, if your countries laws say this closed system is a law and you have regulatory inspections in your country.)
No more oil vapour into your intake line. This is very similar solution to the Subby oil separator mod on those c230Ks with the oil vapour issue into the intake line and contaminating the MAF, etc.
So, let me see if i understand. Is it " normal " or " OK " to have oil there? if so, wouldn't it be contaminating and messing the THROTTLE BODY?, If i do what you suggest with a larger hose, should i cancel " tap " the hole in the intake tube where the hose connects ?
So, let me see if i understand. Is it " normal " or " OK " to have oil there? if so, wouldn't it be contaminating and messing the THROTTLE BODY?, If i do what you suggest with a larger hose, should i cancel " tap " the hole in the intake tube where the hose connects ?
It's not normal. Do a search on the w202 forum section "maf oil" or "oil in air filter box" and it's a known problem of oil getting into the intake /maf lines causing alot of problems. I was surprised to read that your model has (as describe by Dirgesan) your oil separator under the valve cover. Access that for replacement or fixing without first pulling the valve cover off??
Mercedes design - I wonder sometimes what the designers were smoking that day they finalized this idea.
Yes, it would be contaminating and messing the THROTTLE BODY.
The solution?
As suggested in my last post, and plug up the hole into the intake line where the short stubby was connected to. You dont need to vent back any of the oil vapours from your valve cover.
This is similar to what can be done on a w202 c230K oil separator valve hose(s) connected to the airbox. (
connected to the oil separator, rerouted and vented down below into the (atmosphere) engine bay and the airbox hole plugged up). For the C230K, oil contamination also affected the I/C.
Once this is done, no more oil contamination issues.
attached to the c230K oil separator and re-routed down into the engine bay opening below where it vents out into the atmosphere. (previously connected by oem hose to the airbox)
(2) airbox connector plugged up and sealed. (previously connected by oem hose to the oil separator shown in the first photo)
Results: no more oil contamination into the I/C, intake line to the throttle and the MAF.
Thanks a lot for the info, i will be doing that!
when the time comes to change the valve gasket, i will then replace the oil separator.
one last question, is it normal that burns oil? i mean, if it goes to the atmosphere or if it goes to the intake tube, it still burning oil, which eventually will translate in lack of oil in the engine, is this normal?
Again, a lot of thanks, you have been very helpful, regards from the borderline in texas-mexico amigo
Thanks a lot for the info, i will be doing that!
when the time comes to change the valve gasket, i will then replace the oil separator.
one last question, is it normal that burns oil? i mean, if it goes to the atmosphere or if it goes to the intake tube, it still burning oil, which eventually will translate in lack of oil in the engine, is this normal?
Again, a lot of thanks, you have been very helpful, regards from the borderline in texas-mexico amigo
I dont know if you need to replace your oil separator, but when you open up the cover, it is a cheap replacement.
I don't think I would use the term "burning oil", that is another issue.
The system you have with the short stubby hose going back into the "system" was the design MB used to recovery any oil vapour/ fumes. It's essentially a closed system to operate oil consumption efficiently (and protect the environment from excess pollution). Unfortunately, this closed system has flaws and can result in oil contamination into the intake throttle system (not good for you).
If your concerned about your engine burning oil or excessive oil consumption, note that burning oil is natural with our cars, but it shouldn't be alot. (example: in normal driving, 1quart in 10K miles is not unusual).
Checking your oil level regularly is important. The days of full service gas stations are gone when they "checked under the hood" for fluid levels. Driver's dont even check their windshield wiper fluid levels, EVER, let alone the oil, steering, tranny fluid, coolant levels & even air tire pressure. lol.
Check for soot, etc that doesn't belong. example: caked build-up on the engine or anywhere in the engine, you've got potential problems. Head gaskets tend to go out on most, if not all w202's, and older MBs, in general.
I would always do a thorough engine cleaning (take detailed photos before) and then more after the cleaning and monitor regularly for any leaks and build-up of grime, oil in the key places you would expect a leak. I always lay down on the garage floor a large section of a flattened cardboard box to keep a tab on any oil or leakage that comes from the bay.
GL my friend.
I would try just cleaning the restrictor, if it is clogged. Inside, there's no moving parts; it's just a washer, sometimes plastic, with a very small hole drilled through it. Over time that hole can get clogged and might cause your problem. One thing: that hole is a fixed size and the ECU is programmed for it, because it's essentially a small vacuum leak. In other words, it's not a good idea to run something through the hole that can enlarge it. My C230K has a restrictor with a check valve in it to prevent air from the manifold to enter the engine, because the supercharger can cause the manifold pressure to be higher than the crankcase. The Service Manual says to replace this valve. But on my Jeep, which has a plain restrictor like the C220, my Factory Service Manual says to remove the restrictor and wash it in soapy water, since the washer inside is plastic. I can't see any reason not to remove yours and wash it, again, if it is clogged.
I would try just cleaning the restrictor, if it is clogged. Inside, there's no moving parts; it's just a washer, sometimes plastic, with a very small hole drilled through it. Over time that hole can get clogged and might cause your problem. One thing: that hole is a fixed size and the ECU is programmed for it, because it's essentially a small vacuum leak. In other words, it's not a good idea to run something through the hole that can enlarge it. My C230K has a restrictor with a check valve in it to prevent air from the manifold to enter the engine, because the supercharger can cause the manifold pressure to be higher than the crankcase. The Service Manual says to replace this valve. But on my Jeep, which has a plain restrictor like the C220, my Factory Service Manual says to remove the restrictor and wash it in soapy water, since the washer inside is plastic. I can't see any reason not to remove yours and wash it, again, if it is clogged.
Thanks for the info, where would that restrictor be in my c220? what should i be looking for?
I'm not sure how your C220 is, but on my 1999 C230K the check valve is on the bottom of the intake manifold just behind cylinder 2, as shown in the first pic. The second pic (close-up) shows where the pipe connects to the crankcase just behind the power steering pump, and the 3rd shows the pipe running from the check valve to the crankcase. Yours should be similar. Your problem might not be this but it doesn't cost anything to check it. If you disconnect it at the crankcase, you should see engine vacuum on the pipe if it's working. If not, I think removing the restrictor could be a pain, without removing the intake manifold. But I do imagine there has to be some kind of safe solvent to spray in the pipe while the engine is running to clean it.
Good info....
For Magodeoz73, there's no real point in tearing this all apart on account of the oil (film) coming in as he shows. I always say, simple steps/procedures is my motto and before tearing all of this apart on a whim.
Magodeoz73 can do whatever he wants first, but a simple redirect using the subby mod (with proven effectiveness) goes a long way. Even if it is clogged, which it probably is based on the amount of oil film he showed us (and I not even sure how long this issue of his has been going on for - maybe or months, who knows except him....) to prevent any further oil fumes getting into the intake side, (unless their another issue somewhere else tht's allow oil vapours to get into the intake as he shows) he probably needs to redirect the stubby hose connector, block off the connector on the intake side, clean up the intake side oil film he has and call it the day and monitor this situation to see if any more oil film shows up on the intake side.
As he said, he can tackle that part/procedure you described when he has the time, $$ to do so along with anything else associated with that tear down.
11-12-2018, 01:18 PM
