OM642 (Euro V) Sooty Tailpipes - Is There a Problem?

E55BOF

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The car is a 2013 CLS 350 CDI with the OM642 engine, Euro V (DPF but not Adblue) specification. It has been remapped at PCS. It has done 70K miles.

The tailpipes are noticeably sooty. Is this normal for a Euro V OM642, or do I have a problem? The iCarsoft says all is well, but I was under the impression that tailpipes on DPF-equipped cars should not be sooty.

It passed its last MoT with a Smoke Opacity figure of 0.30; the maximum permitted is 0.50.

Are there any other owners of same-spec OM642s who would comment on whether their tailpipes are also sooty, and maybe whether my Smoke Opacity figure is in the same region as theirs?
 

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The car is a 2013 CLS 350 CDI with the OM642 engine, Euro V (DPF but not Adblue) specification. It has been remapped at PCS. It has done 70K miles.

The tailpipes are noticeably sooty. Is this normal for a Euro V OM642, or do I have a problem? The iCarsoft says all is well, but I was under the impression that tailpipes on DPF-equipped cars should not be sooty.

It passed its last MoT with a Smoke Opacity figure of 0.30; the maximum permitted is 0.50.

Are there any other owners of same-spec OM642s who would comment on whether their tailpipes are also sooty, and maybe whether my Smoke Opacity figure is in the same region as theirs?
Has the remap caused a little over-fueling?

Unable to comment in direct comparison as my standard OM642 is the 224 hp version without a DPF but it had a smoke opacity figure of 0.18 at the recent MOT and whilst there is some soot (due to not having a DPF) there is not a great amount of it in the tailpipes
 
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E55BOF

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Has to be the BS 156 come on 😉

Has the remap caused a little over-fueling?

Unable to comment in direct comparison as my standard OM642 is the 224 hp version without a DPF but it had a smoke opacity figure of 0.18 at the recent MOT and whilst there is some soot (due to not having a DPF) there is not a great amount of it in the tailpipes.
That's not a good sign... My car has a DPF, yours has not, but your Smoke Opacity value (and by the sound of it possibly the soot in the tailpipes) is better than mine.

I'd have thought that the DPF should pick up all the soot, remap or not, but I don't know all that much about diesels. I'll wait and hope that some other owners will post; it's early days yet.
 

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Is there any noticeable smoke on brisk acceleration?
 

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My non dpf om642 has sooty tail pipes , all other diesel dpf cars I see have clean shiny one‘s
 

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Denis my 350 also has sooty pipes which clean regularly. My car is not mapped. It passed its mot yesterday with no issues at all.
If you look at other 350s, you’ll see they are sooty too but, look at a 220/250, they’re not It must obviously be how their emissions work. Their exhaust tips remain clean.
 
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E55BOF

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Denis my 350 also has sooty pipes which clean regularly. My car is not mapped. It passed its mot yesterday with no issues at all.
If you look at other 350s, you’ll see they are sooty too but, look at a 220/250, they’re not It must obviously be how their emissions work. Their exhaust tips remain clean.

Thanks for that; that's very helpful. I take it you mean that you clean your tailpipes regularly? What was your Smoke Opacity figure yesterday, and what mileage has your car covered?
 
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OneForTheRoad

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do mots places even test cars down to the levels thats expected , where i go if it dont smoke when revved they pass it . another place i use has a wireless/bluetooth tester that absolutely hates mercs , so they dont even bother using it anymore.
 

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do mots places even test cars down to the levels thats expected , where i go if it dont smoke when revved they pass it . another place i use has a wireless/bluetooth tester that absolutely hates mercs , so they dont even bother using it anymore.
So you are saying that these Test centres make up a smoke value?

I thought that the reading from the smoke test was digitally stored into the MOT testing system.
 

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I've had a look at my Euro 5 OM642, to confirm my original thoughts that it was clean; I can't see any soot, stuck finger in and it came out clean!

I can't find last year's opacity reading but previous year was 0.1%, prior to that a couple at 0.03% and one 0.0%. Car has done c40,000 miles but vast majority on Autoroutes. They're very small percentages, including your 0.3%, so not sure how much should/can be read into the varying figures.
 

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Thanks for that; that's very helpful. I take it you mean that you clean your tailpipes regularly? What was your Smoke Opacity figure yesterday, and what mileage has your car covered?
It passed at 0,25 for smoke and has 79k on it. I treated the tailpipes with ceramic coating years ago and a simple wipe with a damp kitchen roll cleans them up.
 
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As HB has already pointed out it is perfectly normal for the tail pipes to get covered in soot on OM642 W218 CLS 350 cdi so do not worry.

You say you had it remapped it at PCS. Was it just a generic file uploaded by them on behalf of a third party i.e. Celtic?
 
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E55BOF

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You say you had it remapped it at PCS. Was it just a generic file uploaded by them on behalf of a third party i.e. Celtic?
I did not have it remapped; the owner before last did. I've had a lot to do with another organisation named PCS recently; slip of the tongue. For PCS read MSL, and you can't get much better than that...
 

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