Oil In Air Intake

[BlackC55]

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

They can be replaced with the head in situe. They are bl00dy tight but possible.

The repair method is so very common now. I see so many of them.

I have the MB repair proceedure and follow it strictly whenever I do one.

 

[jamesmc]

Thanks for the input guys... just what I needed.

 

[jibcl500]

Very interesting topic. Ive recently replaced the MAF on the wifes 230K SLK, its been fine for the last few months and then a problem started, hesitation on acceleration. The diag computer didnt pick up anything.
I read this topic this morning and decided to find the valve under the inlet manifold, its not electrically powered on the SLK, anyway the valve was black with carbon so I soaked it and gave it a good clean, removed all pipe work and cleaned them and everyhting now seems as good as new.

thanks people.

jib

 

[ProfessorX]

Dear All
The part numbers very kindly listed are they the same for the C230K? (w202)
If not I will spend the time trawling the parts list to try and identify them - just have a concern I will end up with the wrong ones lol.
Apologies to those I have not been around in a while few other issues to deal with. I have cleaned my MAF several time since my previous poor running issues and I have also had someone clean the breather pipes but I still seem to get oil in the intake and MAF so I am worried I have a more serious issue, though I will try all other work including actually "new" parts rather than cleaning and see if this resolves the problem.

 

[jimsinessex]

They can be replaced with the head in situe. They are bl00dy tight but possible.

Excellent news! As they were a press fit in such an awkward position I just assumed it was next to impossible to do them in situ.

Jim

 

[jimsinessex]

Dear All
The part numbers very kindly listed are they the same for the C230K? (w202)
If not I will spend the time trawling the parts list to try and identify them - just have a concern I will end up with the wrong ones lol.
Apologies to those I have not been around in a while few other issues to deal with. I have cleaned my MAF several time since my previous poor running issues and I have also had someone clean the breather pipes but I still seem to get oil in the intake and MAF so I am worried I have a more serious issue, though I will try all other work including actually "new" parts rather than cleaning and see if this resolves the problem.

Yes, the parts are the same.

You say someone has cleaned the breather pipes without solving the problem. If they didn't remove the inlet manifiold (and the bill would include 4hrs labour for that) then they have cleaned the high load breather pipes and oil separator mounted on the top of the engine. These are not the culprits. The problem parts are under the inlet manifold. After replacing these make sure the air intake pipework between kompressor and throttle body is cleaned as well as the air cooler otherwise the residual oil will still cause MAF sensor problems.

Jim

 

[BlackC55]

Yes, the parts are the same.

You say someone has cleaned the breather pipes without solving the problem. If they didn't remove the inlet manifiold (and the bill would include 4hrs labour for that) then they have cleaned the high load breather pipes and oil separator mounted on the top of the engine. These are not the culprits. The problem parts are under the inlet manifold. After replacing these make sure the air intake pipework between kompressor and throttle body is cleaned as well as the air cooler otherwise the residual oil will still cause MAF sensor problems.

Jim

Bumper has to be removed to clean out the intercooler.

Most of the cars I have done all of the flexi rubber pipes have been rock solid.

 

[ProfessorX]

jiminessex - thanks for the note regarding the different breather pipes.
"and the bill would include 4hrs labour for that" I certainly didn't get charged 4 hours labour so I am suspecting this is the case. With this in mind I will be taking the car somewhere else and instead of being cleaned will insist on the piped being replaced.
Thanks again

 

[jamesmc]

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

Malcolm

I was wondering....

As Jim has put so much work into this would there be scope for him to add a post, summarising all his findings, into a the DIY how-to section?

That way all his hard work would in effect be saved for the future benefit of others.

 

[dunnie911]

same problem !!

Hi Guys
Great forum!
I have the same problem hence the search on the net.
i have a 99 slk 230 komp oil everywhere air filter is drenched
i was told at first it was the charger, the car has the symptoms
missing/backfire, wont rev when idle you can put the pedal to the floor
and it does nothing mostly cuts out
anyway I then got told by a MB tech it couldnt possibly be the charger
to clean everything and the problem will go away!! he said that it was
probably caused by putting to much oil in the system HA and they charge how much for this crap! lucky the info was free!
anyhow im going to print out your advice and take it to my friend who
is stripping the car tomorrow I will let you know how I get on.
thanks for your advice I hope its the cure! soon find out
speak soon
ian

 

[jimsinessex]

Part Number Correction

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.

A sharp-eyed member has pointed out that the wrong part number has been quoted for the nozzles. The correct number is MA111 017 00 12

Apologies to all and thanks to Jamesmc who spotted it!

Jim

 

[C240yaz]

I have just read all of this from start to finish on the actual problems that arise and repairs needed on oil contamination to the air supply, MAF included. Co-incidently, the most likely route cause does not seem to be have, been included.

Many of these problems will be caused by worn valve seals, especially on 90K plus mile engines ?

More back pressure is pushed into the block from worn/burned out valve seals than anything else, especially on the exhaust valve seals, which run hotter and become brittle. Piston rings are second on the list, so this would be my first diagnostic repair. Petrol and diesel engines included. Worn valve seals causes breather problems.

This is normal decoke maintenance after this type of milage on all engines, no matter if MB or other, seals are made from the same material. Rubber/Silicon... and burn out, especially if infrequent oil changes are in the history, or the engine has had a roasting at some point in it's lifespan. (All it takes in one day, stationary, stuck in traffic on the M6 on a hot day for an hour) Hence, brittle hoses, blocked breather pipes, oil deluge in the airflow and MAF problems.

Correct me if I am wrong, but I have seen this many times and it is overlooked.

 

[jamesmc]

I feel that your logic is fine and the points you make are valid.

Worn valve seals causes breather problems.

But I would suggest that that on any engine (worn valve seals/rings or not) if the breather system nozzles were blocked you would probably end up with the same symptoms .....oil eventually finding it's way to the MAF.

It's doubtful that a new engine would have blocked nozzles so, short of blocking them deliberately to prove it, this could be a mute point on the debate front.

When you look at jiminessex's solution to stopping oil migrating to the MAF it seems that a car that was getting sick appears to be cured (as such) and reported as running well as a result. If the nozzles hadn't blocked then the engine would have been running just as well as it is now and no one would be wondering too much about worn valves guides/seals/rings at all.

I guess if your engine has 'oil on the MAF' type problems and you spend 20 odd quid on bits and unblock a couple of nozzles, with your car is running well as a result, you would probably be unlikely to go down the valve guide, piston ring change route any time soon unless a compression test proved otherwise.

Maybe the train of thought here is unblock something that is blocked first and see if that cures the problem.
If not... start looking elsewhere.

 

[television]

There are some more mods out now for cars with oil in MAF and breather pipes

 

[C240yaz]

I feel that your logic is fine and the points you make are valid.



But I would suggest that that on any engine (worn valve seals/rings or not) if the breather system nozzles were blocked you would probably end up with the same symptoms .....oil eventually finding it's way to the MAF.

It's doubtful that a new engine would have blocked nozzles so, short of blocking them deliberately to prove it, this could be a mute point on the debate front.

When you look at jiminessex's solution to stopping oil migrating to the MAF it seems that a car that was getting sick appears to be cured (as such) and reported as running well as a result. If the nozzles hadn't blocked then the engine would have been running just as well as it is now and no one would be wondering too much about worn valves guides/seals/rings at all.

I guess if your engine has 'oil on the MAF' type problems and you spend 20 odd quid on bits and unblock a couple of nozzles, with your car is running well as a result, you would probably be unlikely to go down the valve guide, piston ring change route any time soon unless a compression test proved otherwise.

Maybe the train of thought here is unblock something that is blocked first and see if that cures the problem.
If not... start looking elsewhere.

I did not mention a new engine at any point. I was refering to 90K plus engines. If you re-read my post you may see this.

Niether was I refering solely to Jimsinessexx problem or "Nozzles". The post was launched well before then and I was reading the thread as a whole, from the start to the end, regarding engine breathing.

Note: A compression test is not an accurate method for checking the condition of valve seals. Valve seats, rings and gasket, yes.

 

[jamesmc]

calma calma

Worn compression components were mentioned earlier..... maybe just not in so much detail.

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

 

[C240yaz]

Point taken. Apologies and Thanks.

 

[jamesmc]

There are some more mods out now for cars with oil in MAF and breather pipes

Malcom,

Are these official MB mods? Any on the W208? If so, do you have any details?

The reason I ask is I'm about to tackle the oil breather system.
I now have most of the parts to replace the crank case oil breather check valve & hoses (lower load system under the inlet manifold), cylinder head cover oil separator plus associated hoses (solid as a rock) plus the one that heads off and connects to the dip stick tube is split already.

 

[jamesmc]

I asked a lot of questions and received a lot of helpful answers, so the least I can do is try to offer something by way of return...........


Just before I left home (offshore now working on some pipeline spool pieces halfway between Holland and England) I tackled the job.

First I disconnected any necessary pipework... fuel lines etc.
I removed all the manifold bolts including the two extended reverse torx extended bolts which, as well as securing the fuel rail (for want of a better expression), also act as manifold securing bolts.

I took the inlet manifold off, but didn't remove it completely.

Pulling the manifold away from the head and to one side a little gave me enough access to do what was needed. I suspended the bulk of the weight from the bonnet using bungees so that (in effect) it was floating, almost weightless, to one side.

Both of the smaller pipes, which connect to the underside of the nozzles, were brittle as mentioned earlier in this thread. They simply snapped off with very little effort. Hence (as suggested by JiminEssex) the need to ensure you have all the parts you need before getting stuck into this job.
The rest of the brittle hose remaining on the nozzle tube connectors I gently snipped off with a pair of small light duty side cutters.

On inspection, and with a squirt of WD40 via a small tube up the disconnect nozzles, I noted that the forward brass breather nozzle was about 90% clogged and the rear nozzle 100%. So not a lot of breathing going on there!

After checking the existing nozzles I decided that (although push fit) they had resided in that position since 1999 and, although I had two new replacements, I decided to leave them in situ. It was the safer option in my mind.

I checked the bore size of the new nozzles and cleaned the existing ones out using a small drill bit (I should have taken note of the size for this forum ... sorry), tooth picks and WD40 to flush out the debris. End result? Two clear nozzles to original spec.

The Valve 'T' Piece was looked a bit choked up too when I investigated further.

I replaced the inlet manifold gaskets with two new ones and reassembled.
The Intake Manifold Bolts were torqued to 20Nm

I've added a few images to give people some idea of how these nozzles and the pipe runs look in situ.

Image 1: Forward nozzle, pipework and Valve 'T' Piece
Image 2: Forward nozzle, pipework and Valve 'T' Piece
Image 3: The rear nozzle 100% clogged
Image 4: The pipework & T Piece as they came (snapped!) off

 

[fouskos]

James,

I have two questions:

1.Is it possible to clean these nozzles without taking off the manifold?
2.Is it possible that this blockage can cause oil consumption?

andreas