W204 OM646 C200 C220 CDI PCV Crank Case Vent replacement

dickybow

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Hello

Car: 2008 W204 C200 CDI with OM646 engine with 180,000 miles


I suspect the PCV on the top of the engine is failing. There is a fine mist of oil all around it and smoke comes out of the vent hose.

Engine has consumed 2 Litres of oil in 6000 miles.

unnamed.jpg


The part number stamped onto it is A6460101130 but seems to be all one piece with the valve cover, unlike other Mercedes tutorials I have flicked through which show separate removal of the PCV on different cars.

Entering the part number into Google shows pages of the PCV integrated with the valve cover :

A-646-010-11-30-Auto-Valve.jpg

A-646-010-11-30-09-301.jpg


I am a little confused however because this parts website shows A6460101130 to be the valve cover with the PCV separate - although this may be incorrect? :

A 6460101130 CYLINDER HEAD COVER CLICK



a3440124607db939a6555d7ce7abec24.gif


Could anyone kindly clarify whether the PCV is a serviceable part on my car ?

Many Thanks
 

umblecumbuz

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Looking at my similar car (S204 with 646) with a similar mileage and comparing it with your photos and exploded drawing, it seems as though the PSV is one assembly which includes the oil filler opening (item 50 above) that somehow slots into place in the valve cover. It also appears to need the valve cover removing before the PSV assembly can be removed/replaced.

This doesn't really answer your question about serviceability, but it does indicate that the PSV can be bought separate from the entire cover.

If it's possible to prise off Item 50 without removing the valve cover, the answer should be fairly evident. Be interested to know how you get on.

Umble
 
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dickybow

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Sorry for the late reply.

I never got any further with this.

Item 50 which you refer to is not held with a bolt as the diagram shows and curiously enough it all seems to be one moulding.
 

e55amggary

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Your pcv will be the same as the one on our 2005 w203

I had this exact issue

You can buy the pcv on its own from mercedes ( approx £100 i think)It just bolts on with a large o ring underneath ( 60 - 55 in diagram)

I replaced the o rings on the pcv which did improve things, also worth putting a jubilee clip at the end on the breather pipe ( 70 ) to pcv. Also get a new engine oil filler cap.

When i removed mine there were no blockages, all seemed well.

I still get a misting around ours as i did not go for a new pcv, but i know if i did replace it i would have rectified the misting issue.

As our car is at 160k i put it down to wear and tear.
 

Matej

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Hello there,

@dickybow: did you manage to solve the issues?

Thanks!
 
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dickybow

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To confirm, part 50 in the diagram above is Part Number A6460101262

This photo below of a used item clearly shows bolts that my car does not have

s-l1600.jpg
 

Matej

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That's right.
It seems to be t he same PCV as from functional perspective but the difference is the valve cover itself. It seems that older versions used in W203 for example were using the two separate parts - the cover itself + pcv and unfortunately, our W204 OM646 is havind 1 piece valve cover + pcv only.
For me it doesn't seem to be repairable any other way but replacing whole valve cover ...
 

AlexAndreev

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I know this is an old conversation but the following may be useful to a lot of owners of w204 c220 cdi with the 646 engine.

The PCV in the engine cover can be replaced on its own by popping the small round black cover off with a large flathead screwdriver prying on each side equally and slowly as to not break the clips holding it in place.
Under the cap is the rubber pcv membrane which can be ordered off ebay or any parts store for around 20pounds. It is usually a little stuck in place but can be lifted with a small flathead screwdriver and removed. It comes out with the spring and is installed in 2 minutes. If you cant find the part it should be the same from w203 where the whole assembly can be purchased and the membrane can be used.
I changed mine today from a cover that i bought second hand and the performance of the car is brilliant!
If you have one of these cars... pop the cap off... check the rubber membrane and if its torn swap it out. You don’t need to spend hundreds on a whole new valve cover and have to remove the injectors etc to change a part that can be swapped out with a flathead in 2 minutes.

I hope i’ve been of some help!
Cheers!
 

Matej

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Hey Alex,
Thanks for an update.

I forgot to update - i've ordered used one from mercedes medic and replaced it.
No more oil consumption ;)

Could you provide link to that membrane? I'll probably get one and replace it on the old cover to have one as a spare in case of need.
Thanks!
 

madasar

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I know this is an old conversation but the following may be useful to a lot of owners of w204 c220 cdi with the 646 engine.

The PCV in the engine cover can be replaced on its own by popping the small round black cover off with a large flathead screwdriver prying on each side equally and slowly as to not break the clips holding it in place.
Under the cap is the rubber pcv membrane which can be ordered off ebay or any parts store for around 20pounds. It is usually a little stuck in place but can be lifted with a small flathead screwdriver and removed. It comes out with the spring and is installed in 2 minutes. If you cant find the part it should be the same from w203 where the whole assembly can be purchased and the membrane can be used.
I changed mine today from a cover that i bought second hand and the performance of the car is brilliant!
If you have one of these cars... pop the cap off... check the rubber membrane and if its torn swap it out. You don’t need to spend hundreds on a whole new valve cover and have to remove the injectors etc to change a part that can be swapped out with a flathead in 2 minutes.

I hope i’ve been of some help!
Cheers!
hi mine is also leaking I've just order an w203 part hopefully it fits the w204 as i couldn't find one for my car. also you mentioned performance how does it effect the performance ?
 

madasar

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20210407_182225.jpg
This is what my pcv looked like damn.
 

Dionis

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Hello there ,

I have the same problem. Did the w203 part fit for the w204 in your case?

Many thanks
 

madasar

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Hello there ,

I have the same problem. Did the w203 part fit for the w204 in your case?

Many thanks
Hi there sorry for the late reply I just seen this message in my junk mail. Also yes it fitted but it hard to remove the pcv from w203 but very easy on the w204 hope this answers your question.
 

Dionis

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Hi ,

Yes it does answer my question :). I am currently waiting for the part to come so no problem for delayed reply.
Any suggestion on how to remove the PCV cap?

Many thanks ,
 

madasar

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Hi ,

Yes it does answer my question :). I am currently waiting for the part to come so no problem for delayed reply.
Any suggestion on how to remove the PCV cap?

Many thanks ,
The w204 cap comes off very easy with a flatface screw driver but the w203 is a different story altogether taking the cap off that was very hard.
 

Dionis

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Thanks, I appreciate it. Can't wait to try it
 

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