Oil In Air Intake

jimsinessex

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television said:
Hi Jim, the crankcase breather goes into an oil seperator, on the bulk head, inline with the windscreen wiper there is a pipe clamped to bulkhead, there is another pipe coming up from the left hand side over the engine, this pipe goes into a venturi nozle and joins the other pipe. that is the crankcase breathing valve, right in the center of engine on top, lefthand you have a black box with rwo pipes, one going left and the other coming from front, that's the oil seperator,
The reason for the problems is an vacuam issue that follows the cold start with a large number of loads switched on, really the vacuam lines should be replaced along with the crankcase ventilation hose from oil seperator to air cleaner.

Malcolm, the work sheet ref is AF43.10-P-3400AC get MB to run you off a copy. this is specific to your car.

I obtained the worksheet and the pic referring to my car (W208347) shows the pipe coming over the engine right enough, problem is it doesn't exist on my car. I have had the car since new, supplied through normal UK channels (i.e. NOT a grey import) so I know it has not been modded in any way.

ALL the various models on the worksheet seem to have a connection teeing into the vacuum line between the brake servo and the downstream side of the throttle buttefly. that vacuum line on my car is just a straight pipe with no tapping points. The plot thickens! The separator you refer to on top of the cylinder head cover has already been renewed and all associated pipes to that separator and air cleaner plus the very small pipe (not mentioned anywhere so far) from inlet to separator and going to the kompressor body all checked clear.

It looks like the problem is under the inlet manifold somewhere as indicated by "severn" and "tech lee". I am hoping to get the car over a pit soon to investigate further but fear access will be grim!

Thanks to all for their contributions so far.

Jim
 

G MAN

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Jim did you resolve this issue as it may shed light on my current crisis. If you've been watching the forum you may have seen I've been told it is kompressor failure that causes the symptoms you were experiencing.Any updates with your issue welcome.
 

jimsinessex

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I think I may have sorted it out but only got the car back today so I will hold fire until I am sure. As soon as I am confident I will report back on the solution, hopefully in a couple of days. I must say the idea of the kompressor being the culprit is a new and alarming one, not to say expensive.

In the meantime have you done a compression test, worn valve guides would overpressurise the crankcase emission system and is easily checked. That was not the prob in my case, I have replaced ALL the emission system (it is in two distinct sections) and will post back in detail if it has solved the problem.
 

jimsinessex

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At last, problem sorted

The following applies specifically to my car, a 1999 CLK 230k Coupe with a 208347 chassis no. and a 111975 engine, I believe the info applies to all 202 C class and 208 CLK class kompressor engines.
At 97,000 miles I became aware of oil in the air intake but it was then only a minor irritation, cleaning the MAF sensor sorted it. By 140,000 miles the amount of oil in the pipework to the MAF sensor was becoming alarming although it only caused a misfire and was solved again by cleaning.
Examination of the air filter housing showed the oil was entering the system from the Crankcase Breather System.

My understanding of the Crankcase Breather System:-
It operates in two modes, an upper partload to full load system and an idle to upper partload system.

The idle to upper partload system works directly off the crankcase and feeds into the cylinder head just before the inlet valves. The high load system from the cylinder head cover feeds into the air filter housing AFTER the the filter element.

The highload system is mounted on the cylinder head cover and consists of a black plastic oil separator and three hoses,it is very accessible and cheap to replace all components. Beware, get the parts first as the hoses are brittle with age and at least one will probably break. Changing all this did not solve my problem although it was clear that the oil was coming from here!

Conclusion - idle to upper partload system was blocked and forcing the highload system to accept the oil residue at low airflows.

The lower load system is hidden under the inlet manifold and consists of an oil separator built into the crankcase with a hose leading to a valve and tee-piece which in turn leads via two small bore hoses into two brass restricter nozzles in the cylinder head just before the inlet valves. The valve is spring loaded and NOT (in my case) the electric valve suggested in earlier replies. This system was blocked on my car and causing the problem.

After replacing all of it the problem seems, after a further 1000 miles, to be sorted.

Part numbers were:-
Main hose - MA111 018 15 82
Valve/Tee-Piece complete - MA111 010 00 91
2 small bore hoses - MA 002 094 01 82
2 Nozzles MA202 270 33 96

Again the hoses were brittle with age so order before disturbing them.
The nozzles have a very small bore but are a press fit in the head so unless the head is off best to just poke them through. They are only 97p each so order them anyway in case.

I would strongly suggest the Kompressor outlet pipework and intercooler is cleaned as well as a lot of oil could be lying here and still cause problems even after the breather systems have been renewed.
 
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G MAN

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You've done some serious detective work there Jim & hopefully you've sorted not just your problem but mine & many others who no doubt have been baffled & then robbed by technicians who can only work in one dimension of codes. This diagnosis is so refreshingly well researched, presented & shared in an uncomplicated ,non-mystifying way for the benefit of the rest of us . Well done mate & thanks for the guidance.
Mines a 111 956 kompressor by the way but all the probs. & symptoms are just the same. Will get on with it & post back my contribution!
PEP needs to see this too
 

jimsinessex

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One initial check I would strongly recommend is to do a compression check. A worn engine, either bores or valve guides, is the most basic cause of overpressurising the crankcase. Hopefully our engines are nowhere near that stage yet.
In my case it was worthwhile as it showed a small drop in one cylinder which turned out to be very slight leakage between cylinders, not enough to have caused damage but left undetected no doubt a blown head gasket and all the attendant hassle would have followed.
As the head had to come off it the work dovetailed nicely with allowing access beneath the inlet manifold.

Good luck, Jim
 

jimsinessex

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G MAN,

How did you get on?

As you may have seen the problem has surfaced again on a more recent thread.

I am interested to know if anyone has had to replace a kompressor as you were originally told to solve this problem as I felt that was a red herring (but could be wrong of course)

Jim
 

G MAN

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for jimsinessex balal pep mikesmerc etc

Hi jim I've been following the various threads on power loss etc and wondered if the common problem was down to the kompressor but I think not. My car (S202 200K) is with my indie right now as it threw up a fault code again & threatened to die after a 150 mile hi end run(trouble free all summer) It restarted & drove very well since that event but armed with all the collective knowledge on here I,ve left it in.
Today's report is , like your findings , blocked/carboned breather pipes under the manifold.He's stripped it down replaced the bits & an electonic valve(mentioned somewhere on here-I'll be more specific when I've the info.) & all seems well but he will run about for a couple of days & see if the o2 sensor throws up anything.
All our symptoms are similar & depends on how we desribe them as to what may apply but your thorough & detailed research should prove valuable to lots of members with these problems. The kompressor does seem to be a known fault ---& I tried DC Customer service on the goodwill front,who knocked it back with suggestions of relying on full supplying main dealer service history so I didn't pursue it. (though I did refer them to this forum!!)--and I agree that it's an expensive fix and so a dealers probable recommended approach. The oil must come from somewhere & would seem in all our cases the crankcare breathers are the root cause. BTW I couldn't find anybody who would touch or attempt to refurb a supercharger & Eaton themselves ran out of road on my enquiry & haven't followed up with a reply of any worth.
So when I get my car back I'll try & give a precis of the remedy for everyone else & try and post a picture of the engine bay & layout of components as they would all seem to differ (my MAF is on the top R/H side of the engine bay just before the throttle body & very accessible )
 

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Update as subject has surfaced again

Since my "problem sorted" post above I have covered another 17,000 miles with no trace of oil in the air intake system or problems with the MAF sensor.

The suggestion that has cropped up a couple of times that this oil is sign of a failing kompressor is a total red herring, and an expensive one at that! There is no oil supply to the kompressor, it has a small amount of oil in the separate gear chamber between the clutch and the main kompressor rotor compartment. Even if this small quantity of oil could get into the pressurised rotor chamber it would settle out on all the pipework and air cooler long before reaching the MAF sensor.


Jim
 

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With all of the work that went into this,it is a shame that we have no where to keep this info.

Malcolm
 

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With all of the work that went into this,it is a shame that we have no where to keep this info.

Malcolm

Guys, that was some seriously impressive detective work! As of yesterday, I am having a very similar problem with my '98 CLK 230K (auto). My knowledge of engines is embarrassingly limited, so I restricted myself to looking inside the air filter housing. There appears to be oil dripping from one of the pipes connected to the housing, and it's begun to accumulate on the air filter. On the way to work this morning, the car lost most of its power and began to backfire quite a lot. When stopped at a junction, or at very low revs, it felt like the car was going to cut out. I had to manually shift from 1-4 just to get it to my office car park. Not wishing to damage the car any further, I tried to keep my speed under 25mph and kept the revs low.

The RAC have just towed it off to the nearest indie. He specialises in VAG/BMW/Mercs, but should I tell him what I've read here? I don't want to insult the guy's intelligence.

Thanks for sharing the information, this is an incredibly useful forum.

Dave.
 

jimsinessex

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Dave,

It sounds very much as if you have the very problem identified in this thread.

The Mass Air Flow Sensor is situated in the air pipework behind the rad at the nearside. It is held in place by two clips and a jubilee clip, also has an electrical plug attached. The whole thing can easily be removed without any specialist knowledge and there are no pitfalls, even for the least mechanically minded. Remove it and check for oil (oily deposits on the outside of the housing are a real giveaway on the Kompressor engine where the positive pressure in the air intake forces oil past the two joints)

If oil is found, clean the sensor with Iso Propyl Alcohol (avail from Halfords, Maplins, etc) as per the excellent sticky thread at the head of this section of the forum.

If this works then you are mobile again, if it doesn't, unplug the electrical connector referred to above and drive car, if it is better (not perfect, but better) then a new MAF sensor is required.

Either way, whether a new MAF sensor is needed or not, oil in the MAF housing means you need to have the Crankcase Breather System underneath the inlet manifold replaced. I have posted very detailed info about this earlier in this thread.

Parts are cheap, about £20, but the labour is the killer so DO NOT use a MB dealer but a reliable MB independent

I would advise a compression test first just to eliminate a worn engine as the cause, but almost certainly the problem will be breakage/blockage of the pipes or valve in the crankcase breather.

Good luck

Jim,
 

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Hi Guys, This problem sounds a bit familiar, On a few occasions we have had this where oil contaminates the air mass sensor causing limp home, loss of power,We have removed the air mass & gently cleaned, removed the induction pipes & cleaned, & then installed a new oil separator valve on the rocker lid top, all done & no more problems, It sounds like the cause of this fault is the separator valve, what worries me is that MB dealers are aware of this problem & you dont mention if they have installed a new one. John
 

jimsinessex

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I renewed the oil separator and all its pipework on top of the cam cover early in the investigation into my problem and it made no difference. The only valve I could find associated with the crankcase breather system was the one under the inlet manifold. The whole system under there was generally blocked up, replacing the lot solved the problem and 27,000 miles on it has not reappeared.
 

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Dave,

It sounds very much as if you have the very problem identified in this thread.

Hi Jim,

It was indeed a problem with the MAF sensor. Unfortunately, I wasn't in a position to start trying to fix it myself, as I badly needed the car to be operational again as soon as possible. In future, I'll certainly have a go at fixing these sorts of problems myself!

The nearest recommended indie replaced the sensor for €400 (roughly £260). It was the first problem I'd had with the car in two years of ownership, so I didn't mind paying.

I think it was previously mentioned, but the mechanic said it was a known problem with Kompressor models, as they tend to pass oil vapours into the air intake. It made sense to me at the time :)

Thanks for your help.
Dave
 
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jimsinessex

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Nodger,

Yes the problem will manifest itself as a MAF sensor problem but you need to address the reason why the MAF sensor failed.

You did say that oil was appearing at the Air Filter housing, so:-
1) was oil the cause of the sensor failure?
2) was there oil elsewhere in the air intake system, particularly inside the MAF housing and around the outside of that housing, also in the pipework before the throttle body (easy to check - just undo jubilee clips)

If the answer to 2) is yes then it will only be a matter of time before that expensive new MAF sensor fails again. At the very first sign of a misfire, clean it and there's a good chance you will save it!

At the very least all the oil needs to be cleaned out of the air intake path, particularly the intercooler and ideally the cause of the oil ingress sorted out.
This brings me back to what is becoming a hobby horse of mine, the need to replace the crankcase breather system under the intake manifold when oil appears in the air intake of high mileage (say 90k onwards) 230K 111 engines.

Jim
 

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1) was oil the cause of the sensor failure?

My mechanic said that oil was the cause of the sensor failure, but I can only take his word for it.

2) was there oil elsewhere in the air intake system, particularly inside the MAF housing and around the outside of that housing, also in the pipework before the throttle body (easy to check - just undo jubilee clips)

Unfortunately I have absolutely no idea where the MAF is physically located, or what it looks like, so I couldn't tell you. Do you know of a good book/site that has diagrams of where everything is located in a CLK? I'm very much new to all this, so I only know where the (very) basics are.

At the very least all the oil needs to be cleaned out of the air intake path, particularly the intercooler and ideally the cause of the oil ingress sorted out.

He did say that he cleaned a lot of the oil out of the system, but he reckoned it would build up again over time. If I can figure out how to do it, I'll certainly have a go at it myself. My worry is that I would mess it up and kill the car.

Cheers,
Dave.
 

jimsinessex

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Dave,

The MAF sensor is behind the radiator on the nearside of the car (RHD). It is located in a vertical section of the air intake pipework and is fitted in a plastic housing about 6" long and 2" diameter. It has an electrical plug connection on the side and the whole housing is held in place by one jubilee clip and two spring clips.

Couldn't be simpler to remove for cleaning and would be almost impossible to mess up! Only warning - if attempting to clean the sensor don't touch the actual surface of the sensor itself with anything. To clean I just spray with Iso Propyl Alcohol and dry gently with a hair drier. The plastic housing is robust and can be handled without problems.

You don't mention the mileage but from the age of your car I suspect it may be getting to the sort of mileage (90,000+) where the breather system under the inlet manifold is blocked or has brittle and broken pipes. Only solution is to replace them

Jim
 

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Jim

Reading all this at night.

Thanks for all your 'hobby like' research on this. I am sure it will save a lot of people a lot of grief and cash!
I particularly like the fact that you supplied the required part numbers too!

Quick question.
I think I read that the head had to come off your engine so you had the crankcase breather system replaced then (makes sense to me) but, currently the head on my engine has no known reason to be removed.
What is the access like to replace the crankcase breather system under the intake manifold?
I can get my car up enough (on blocks) to get under it or can work from the top and if need be removing pipework to gain access.

I'm just trying to pre-empt future problems by carrying out what, given the age and mileage of my car, I deem as preventative maintenance.
 
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jimsinessex

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Jim
Quick question.
I think I read that the head had to come off your engine so you had the crankcase breather system replaced then (makes sense to me) but, as the head on my engine has no known reason to be removed.
What is the access like to replace the crankcase breather system under the intake manifold?
I can get my car up enough (on blocks) to get under it or can work from the top and if need be removing pipework to gain access.

I'm just trying to pre-empt future problems by carrying out what, given the age and mileage of my car, I deem as preventative maintenance.

The head does not need to be removed to access the breather system but the intake manifold does have to come off. It is NOT possible to even view the system from below let alone work on it. I tried every which way to get at it without removing the intake manifold but it is impossible.

So reckon on 4 hrs labour charge (don't go near a MB dealer unless you are loaded) and £20 for parts. I personally don't think the two brass restricter nozzles into the head can be replaced with the head in situ although one member here was told his indie had done just that. Anyway it's no big deal as they can be poked through, get a new nozzle anyway (only 97p) to size up the drill to use for that, otherwise they could finish up oversize being brass.

If any 202/208 Kompressor owner with 70,000+ miles on the clock ever has to have the head or just the intake manifold removed for other work DO replace the breather system anyway as you have paid for the labour and the parts are only another £20. Every one of these cars WILL suffer the problem when the mileage gets high enough. The hoses go brittle with age and the spring loaded valve clogs up.

The main clue that a problem is brewing, apart from MAF sensor faults, is an oily film on the outside of the MAF sensor housing. I believe the positive pressure from the kompressor does, in time, force traces of the oil to weep past the 'O' ring seal.

Jim
 

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