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dillbar123
Member
So took the DPF off last night and cleaned it also took a pre-cat out and cleaned that also. 
CLS 350 CDI black smoke under acceleration, extremely bad.
- Thread starter dillbar123
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It may serve you well to remember that experienced members are giving there free time in an attempt to help you here so possibly think again before glibly throwing insults at them?
All it does is alienate members from trying to offer help.
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dillbar123
Member
I doubt it will serve me well. What does experienced members mean, experienced at typing? Or actually owning and working on vehicles themselves.It may serve you well to remember that experienced members are giving there free time in an attempt to help you here so possibly think again before glibly throwing insults at them?
All it does is alienate members from trying to offer help.
Because that’s the information I came to seek, people who have hands-on information. Not a comfy chair a keyboard and Google. some people just talk like they watch too much YouTube. And it shows real bad.
I wasn’t throwing insults, I didn’t mean to offend anyone. just sometimes commonsense offends me.
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In that case I suggest that you look at your own reaction to commonsense...
This is an excellent forum with hugely knowledgeable members including many MB trained Specialists and members with more experience in engineering etc than either of us possess
It doesn't matter if someone has used Google or YouTube.
They are still trying to help and deserve a degree of courtesy in response.?
michaelgmurphy
New Member
We had that smoking issue on acceration with the same 3.0L V6 turbodiesel engine - the OM642 - but in a Merc ML W164.
The crankcase breather diaphragm is part of the problem; when the rubber diaphragm in the PCV perishes or goes hard, the air pressure from the turbo intake sucks oil past that worn diaphragm, out of the crankcase, and into the turbo, creating a lot of black smoke on acceleration.
However, that is only half of the issue. The diaphram bolts onto an alloy breather cap on the cylinder head. That alloy cap itself has a plastic seal in it. That seal shrinks and hardens over time, allowing oil to seep past and into the crankcase breather and then on into the turbo intake.
It is a recognised issue with the OM642. The alloy cap should be replaced as a service item, along with the crankcase breather, and the two red turbo intake seals.
Part number of the alloy cap is A6420100131
It is an OEM only part. And costs about £30. We bought from http://www.lllparts.co.uk who import at discount from MB warehouses in East Europe.
After replacing the cap, no more smoking, and we noticed improved fuel economy. Maybe an extra 3 or 4 mpg, and more power and smoother running.
A clear if long-winded video explaining:
The crankcase breather diaphragm is part of the problem; when the rubber diaphragm in the PCV perishes or goes hard, the air pressure from the turbo intake sucks oil past that worn diaphragm, out of the crankcase, and into the turbo, creating a lot of black smoke on acceleration.
However, that is only half of the issue. The diaphram bolts onto an alloy breather cap on the cylinder head. That alloy cap itself has a plastic seal in it. That seal shrinks and hardens over time, allowing oil to seep past and into the crankcase breather and then on into the turbo intake.
It is a recognised issue with the OM642. The alloy cap should be replaced as a service item, along with the crankcase breather, and the two red turbo intake seals.
Part number of the alloy cap is A6420100131
It is an OEM only part. And costs about £30. We bought from http://www.lllparts.co.uk who import at discount from MB warehouses in East Europe.
After replacing the cap, no more smoking, and we noticed improved fuel economy. Maybe an extra 3 or 4 mpg, and more power and smoother running.
A clear if long-winded video explaining:
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dillbar123
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Thanks for your reply I’ll replace that for good measure! Great detailed response thanks for the reply!
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See post #4. Black smoke on acceleration is soot, not burnt oil.
If you're feeling flush, get the whole breather assembly - A 642 010 24 91. That also gets you an improved red rubber seal at the turbo end of the pipe; it is not unknown for the earlier seal, when worn, to be sucked into the turbo, which then also needs replacing. The later design of seal, which is of course not available separately, has locating 'ears' to prevent this happening.
If you're feeling flush, get the whole breather assembly - A 642 010 24 91. That also gets you an improved red rubber seal at the turbo end of the pipe; it is not unknown for the earlier seal, when worn, to be sucked into the turbo, which then also needs replacing. The later design of seal, which is of course not available separately, has locating 'ears' to prevent this happening.
michaelgmurphy
New Member
Did you get the smoking sorted? When you say black smoke, you do mean black smoke?!Thanks for your reply I’ll replace that for good measure! Great detailed response thanks for the reply!
Ahh thanks. Ouch at £110. I bet that new style of breather pipe seal is on AliExpress somewhere, or will be very soon.
We've had amusing experiences of buying aftermarket copies from China only to find they are actually genuine OEM with the Mercedes logo or label superficially covered-over with a sticker!
