oil in breather system

[chalcedony-blue]

thanks again

 

[chalcedony-blue]

update

Hi all especially malcom,
just to update you, we had camshaft cover off and various other parts yesterday, and found the origin of the leak, its coming from the camshaft behind the magnet part, we could see that it had been leaking through at the bottom. It seems that this leak cannot be fixed as there is no seal right back there, the only seal is a rubber seal on the water pipe, i have got one of those from mercedes today and have to wait til wed for this mod part that mercedes say you fit to the front to trap/absorb the oil to prevent it going into the wiring harness! It seems to me from all the posts i have read that this is a design fault/blip with the 208 engines and a few others?
If we are right in our findings,( please if anyone knows exactly how to stop the leak let me know, not just prevent it from travelling,)then it seems once you have this problem you cant actually fix it, only take preventative measures to stop the oil contaminating further parts!! If that is the case, surely all engines with this common fault should be fitted with the mod part and should that not be down to mercedes ie a call back??? Or have i got it totally wrong ??
I must say though I am really enjoying the journey of finding out all about how my cars engine works, but I just want to be back behind the wheel now cos I get so many smile miles to the gallon from it

 

[television]

All you can do is to fit the seal and connector I believe.

There are many things that I could shock you with, where design faults are passed off to the customer to pay.

Give Olly in Portsmouth a ring, he has done loads

 

[jamesmc]

There is no seal for the camshaft magnet sealing face. Yes, there are some design faults on the M111 engine and W208 car but fixes are known for most of them. For example I feel there should have been a seal for the camshaft magnet but, from new, there wasn't. FYI: The magnet is attached by three Allen bolts or 'Torx' bolts on later units.

When refitting the Magnet unit.....
Clean both both sealing faces and apply a thin film of oil resistant instant gasket compound.

I did this job about a year or so back and used Hylomar (sealing compound) because that's what I had to hand. Any instant flexible oil resistant sealing, compound (Like a silicone based instant rocker cover or sump gasket) will do.

I have attached an image of the magnet and the connector (approx 10 'o' clock on the magnet body) That's how it used to look
These days it's clean and not a drop of leakage can be seen.

 

[jamesmc]

Getting back to the oil on the MAF issue. Once the car is running can you report if all is well on overall performance, kickdown etc?

If not the information below would be your next point of attack. Not an expensive item and relatively easy to replace:

This has gone off topic a bit... my fault.

Thanks to all... and to Busby20 for the part numbers. I have now located the check valve. It falls under the compressor section for the engine. For my car (M111.975 engine) the part number is: A002 140 68 60

Item 38 in the image below.

I have seen reference somewhere that the valve is located at the very back of the engine. In this case (W208 CLK230K) it is mounted to the exhaust manifold side of the engine.

The valve can be be seen by peering down between the exhaust manifold. There is a stainless steel bracket/pipe fitted at this point to which the valve is fitted.

Update.

I eventually changed the secondary air injection valve. Once I removed it I discovered that the old one was just masquerading (externally) as a one way valve but (internally) it had failed.
There was quite a bit of crud inside which was compromising the sealing faces. It's a sealed unit so a replacement was required.

The difference in overall performance was quite impressive. The engine now pulls like a train throughout the rev range.
In this instance it appears that the secondary air injection valve was the culprit and was causing MAF like failure symptoms when driving.

For my car (M111.975 230k engine) the part number is: A002 140 68 60
You will need a 27mm open ended spanner to get the thing off. I had to grind down the spanner to make the jaws thinner as the standard 27mm is too thick to fit the flats on the underside of the valve.

It's a DIY job, but you will need to pull the air box and associated pipework off to get decent access to the valve.

 

[television]

Its worth doing what James has done, you may as well do it now as you have most of it exposed.

 

[chalcedony-blue]

will do

hi guys

yep will take the advice and have a look tomorrow

thanks

 

[chalcedony-blue]

update and wiring?

Just to let you know, car is almost back together, new sparkplug shaft seals fitted today, thanks to dad making an ingenious tool to do the job
Got mod wire from mb, plan on putting that on tomo aswell as looking at this secondary air intake valve, so keep you posted on that.
Got qoute from indie in luton £370+ vat + 4 hrs labour to do new harness although my husband (electrician of sorts) is making noises about just replacing the wire that comes from camshaft connector and replacing it all the way back to the ecu as he cant see how the whole harness could be affected, only this part!! Now as you know we are no mercedes mechanics so has he lost his marbles or is this possible? Has this ever been attempted do we know or are we completley missing something???
Keep you posted
Julie

 

[television]

On the wires going up to the ecu, they could be replaced on their own, so fine there as long as any oil did not come back down any others, so the question is how oily are the other ends and what they connect to

 

[chalcedony-blue]

didnt think of that

Thanks so much Malcolm
had not thought of oil travelling back, we will investigate further and let you know.
Many many thanks

 

[television]

You are doing a grand job, well Dad is, the secretary is also on the ball

 

[chalcedony-blue]

trying

I am getting my hands dirty when i can, trust me, but my dad is doing most of it, bless him, everyone should get themselves a dad like mine, they are priceless

 

[busby20]

Just to let you know, car is almost back together, new sparkplug shaft seals fitted today, thanks to dad making an ingenious tool to do the job
Got mod wire from mb, plan on putting that on tomo aswell as looking at this secondary air intake valve, so keep you posted on that.
Got qoute from indie in luton £370+ vat + 4 hrs labour to do new harness although my husband (electrician of sorts) is making noises about just replacing the wire that comes from camshaft connector and replacing it all the way back to the ecu as he cant see how the whole harness could be affected, only this part!! Now as you know we are no mercedes mechanics so has he lost his marbles or is this possible? Has this ever been attempted do we know or are we completley missing something???
Keep you posted
Julie

Hi, I've had this problem in both my SLK 230's kompressors (same engine etc. as your CLK) which required a full harness replacement on both at considerable costs whilst the older of my SLK's has had no problems with oil contamination in the MAF the later one has had constant problems with contamination and the problems that go with it - very annoying!

I have read various posts on Benzworld which address this problem, mostly it points to the "Oil Separator" which is located on the rocker cover between the rocker cover and the kompressor air box. If this is faulty it allows oil to be drawn from the head, through the airbox, down the intake pipes, through the MAF (consequently contaminating it,) and into the manifold.

I noticed that on my older SLK the Oil Separator was attached and visible, however, on the newer SLK there is no visible separator on the rocker cover, just a rubber hose coming directly from the cover into the airbox? so I'm unsure whether the separator is missing, or contained within the cover?

The consensus of opinion at Benzworld is that you can / should bypass the oil separator with a simple modification which will eradicate the problem

I for one, being totally p****d off with this problem will adopt this solution

If you want to find out more just google "Oil Separator SLK" and you will get various links.

 

[chalcedony-blue]

update

Hi everyone
just to update you all. Car drove like a dream, fantastic on kick down, smooth through the gears and perfect to start, I could not stop smiling for 2 days, until yesterday when it all went horribly wrong!!
Cruising home from the dentist, top down, big smile on my face then all of a sudden it started missing. To start with i thought my exhaust was blowing but no, the whole car is shaking on idle and does not really want to go. I limped home and tomorrow we are going to have another look. So back to the drawing board on this one guys????

A very unhappy JUlie

 

[television]

Some oil in the harness still ??????????????

 

[jamesmc]

Hey Julie.... I'm sure it'll be minor as you have not had any major parts off the car if I recollect correctly. Lets just hope it's as TV says... or some other minor DIY type fixable item.

Good luck.

 

[chalcedony-blue]

agree

Hi Malcolm and James
Yes could be oil in harness, we have the starter line attached now but could still be oil from original, so tommorrow we will be changing wiring (would oil in harness make it miss?)
We changed the spark plug shaft seals as one was leaking and put in new spark plugs so think it maybe related to that as it never missed like this with origanal starting problem??

Its very very frustrating!!!

Julie

 

[jamesmc]

I have read various posts on Benzworld which address this problem, mostly it points to the "Oil Separator" which is located on the rocker cover between the rocker cover and the kompressor air box. If this is faulty it allows oil to be drawn from the head, through the airbox, down the intake pipes, through the MAF (consequently contaminating it,) and into the manifold.

If you want to find out more just google "Oil Separator SLK" and you will get various links.

Sorry busby, but I am inclined to disagree with the suggested Benzworld root cause of oil finding it's way to the MAF from the rocker cover.

Please see my DIY post on the subject which also highlights the valuable research carried out by jimsinessex who put a lot of time into this when he owned his W208 CLK230K Coupe. Sadly that car was trashed through no fault of Jim.

I believe the generally accepted cause (on this forum anyway) of oil being forced from the oil separator on the rocker cover is as a result of a failure/blockage of the lower part breather system located under the inlet manifold. As a rule it's the two brass nozzles (fitted to the cylinder head) which block and cause back pressure in the breather system. When this happens an over pressurisation of the upper breather system takes place which then results in oil being forced down the route you describe.
Please see this link for a detailed coverage on the subject.
The fix is cheap for parts but takes a bit of time on the labour front. If the person needing to do the job is a competent DIY mech then it's do-able.

In summary, if the engine (CLK230K W208 or C class W202) has engine oil working it's way down to the MAF from the rocker cover via the airbox then this is the most likely cause.

As an aside.
Sometimes when oil has been seen on the MAF the phrase 'supercharger failure' has been known to be uttered.
Oil seen on the MAF is nothing to do with oil coming from the supercharger oil reservoir itself. The simple reason being that the supercharger does not have a pressurised engine oil feed for the bearings, unlike turbochargers. Plus, if a supercharger bearing seal was to fail the positive pressure of air inside the unit would force what little oil it has (in it's own isolated reservoir) out of the failed seal into the big wide world and not down the pressurised air feed tubing via the intercooler to the MAF.

 

[busby20]

Sorry busby, but I am inclined to disagree with the suggested Benzworld root cause of oil finding it's way to the MAF from the rocker cover.

Please see my DIY post on the subject which also highlights the valuable research carried out by jimsinessex who put a lot of time into this when he owned his W208 CLK230K Coupe. Sadly that car was trashed through no fault of Jim.

I believe the generally accepted cause (on this forum anyway) of oil being forced from the oil separator on the rocker cover is as a result of a failure/blockage of the lower part breather system located under the inlet manifold. As a rule it's the two brass nozzles (fitted to the cylinder head) which block and cause back pressure in the breather system. When this happens an over pressurisation of the upper breather system takes place which then results in oil being forced down the route you describe.
Please see this link for a detailed coverage on the subject.
The fix is cheap for parts but takes a bit of time on the labour front. If the person needing to do the job is a competent DIY mech then it's do-able.

In summary, if the engine (CLK230K W208 or C class W202) has engine oil working it's way down to the MAF from the rocker cover via the airbox then this is the most likely cause.

As an aside.
Sometimes when oil has been seen on the MAF the phrase 'supercharger failure' has been known to be uttered.
Oil seen on the MAF is nothing to do with oil coming from the supercharger oil reservoir itself. The simple reason being that the supercharger does not have a pressurised engine oil feed for the bearings, unlike turbochargers. Plus, if a supercharger bearing seal was to fail the positive pressure of air inside the unit would force what little oil it has (in it's own isolated reservoir) out of the failed seal into the big wide world and not down the pressurised air feed tubing via the intercooler to the MAF.

Hi James,

Have already done this , stripped out manifold, checked pipes - completely clear - replaced rubber tubing, checked valve, took out about half pint of oil from air box at kompressor, thoroughly cleaned, including MAf----fouled up with oil again a couple of weeks later!!

I'm afraid I agree with our American friends, the oil separator malfunction is the key to this (in this instance anyway,)

In the older SLK's (which I also have one of,) the separator is clearly visible on top of the rocker cover, with all the relevant pipework to air box etc., and I have had no problems with this at all, however, on the later types (my newer one, the separator is totally differant, as is the pipework,) and is obviously not functioning properly.

I have bought an old style "rally " oil separator on e-bay (£5) which
I intend to fit and try will let you know how that works-or not!!

 

[jamesmc]

Fair enough then if the lower part breather system was serviced and the nozzles were cleared but the oil on MAF problem persisted you would need to look elsewhere for the cause.

On my W208 CLK230K there is also a separator fitted to the rocker cover, which, due to it's low cost and ease of access, I replaced well before I did the lower part breather system was tackled. For my engine, replacing the upper separator alone did not stop the oil getting to the air box but fixing the lower part breather system (in my case) did. Mind you, no matter how much you clean things by hand, you end up with oil residue in the system for months after but it gradually starts to get a dry look which shows things are on the mend.