320 CDI excessive soot buildup.

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flowrider

MB Enthusiast
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Location
United Kingdom
Car
SL500 (R230) / Audi S5
Is it normal for the exhaust tailpiles to turn black with soot just a week after being cleaned, the rear bumper is also covered in soot just above the tailpipes. I also notice when the engine is turned off there is smoke coming out of the exhaust for a few seconds. My Audi TDI didn't turn the tailpipes black and didn't smoke either!

Thanks

David
 
Your car is equipped with the DPF - diesel particulate filter - and should not issue ANY smoke under any circumstances.

Either you have a serious dpf problem or some other fuelling issue to cause this. If your bumper is becoming discoloured, then something needs attention, and quickly!

I'm wondering if this might be related...
 
Just spoken to my local MB service centre who says that the soot buildup even with the DPF is normal and nothing to worry about, other than the weekly cleaning requirement :(.

David
 
Just spoken to my local MB service centre who says that the soot buildup even with the DPF is normal and nothing to worry about, other than the weekly cleaning requirement :(.

David

I have now discovered that my vehicle does not have a DPF and they can't be retrofitted either, not good news.

David
 
My motor is pre-DPF, and so particulates are free to exit the exhaust system and attach themselves to the back bumper. Only they don't, because the car doesn't generate any noticeable soot to start with.

Your motor should be cleaner still, and then you have the DPF on top of that. As they say - "go figure"...

Can you post a picture of the sooty bumper in question?



Edit to add. I posted this before I saw David's post immediately above...
 
I don't know much about ML's, however, I thought all 2009 OM642's had DPF's :confused:.

Request the datacard from someone on here (generated from the VIN) number and all will be revealed - it will show as a line item if it's fitted.
 
My motor is pre-DPF, and so particulates are free to exit the exhaust system and attach themselves to the back bumper. Only they don't, because the car doesn't generate any noticeable soot to start with.

Your motor should be cleaner still, and then you have the DPF on top of that. As they say - "go figure"...

Can you post a picture of the sooty bumper in question?



Edit to add. I posted this before I saw David's post immediately above...

I can't take a pic of the soot as I have just cleaned it all off. My Audi had a DPF so that would explain why the exhaust was so clean, I thought all modern diesel engines had DPF's.

I have noticed that the exhaust tips are set back a bit from the edge of the bumper so maybe I could pull the tips forward enough to clear the bumper and stop the soot buildup.

David
 
I don't know much about ML's, however, I thought all 2009 OM642's had DPF's :confused:.

Request the datacard from someone on here (generated from the VIN) number and all will be revealed - it will show as a line item if it's fitted.

I contacted MB in Milton Keynes who told me it isn't fitted. Is that a bad thing or a good thing?

David
 
Last edited:
I thought all OM642s (i.e. from 2005) had DPFs.

Well if MB Milton Keynes are correct then no they don't. Is there any way to tell by looking at the vehicle?

David
 
I thought all OM642s (i.e. from 2005) had DPFs.

My 280 CDI is an '09 reg and it doesn't have a DPF (think it was built in '08 though). I was quite specific about that when I bought it as I wouldn't have taken it if it had a DPF.

I do get a bit of soot on the tailpipes, but haven't had anything on the back bumper.

I think it's only the latest EU5 spec diesels which must have DPFs.
 
The datacard is your friend.
 
So we seem to have established that not having a DPF is a good thing but why is it a good thing.

My next question is how can I reduce the soot buildup without have to clean the exhaust tips and bumper every week? Is there some sort of cleaning liquid/wax that I can use to repel the soot?

Thanks

David
 
How do I get a datacard, will MB provide it?

Thanks

David

Hello David,

There are those on here who can provide it if you give them the VIN.

It would be worth asking, perhaps with a new thread, and when you get a bite from one who can provide it, put the VIN on the post and your datacard will be posted on here by return.

It's basically a spec list of everything included on your actual car and makes interesting reading regardless of the DPF.

You could ask now and if no reply, bump it up later tonight when there are a few more people on.

I believe it shows as 926 Exhaust Gas Cleaning with Euro 4 Technology (but I may be wrong).

A dealer can provide if you are passing.
 
Try here, Ìîäåëü

Enter your chassis number, and on the second screen on the top right hand corner there is a link to your datacard with the factory fitted options.

DPF's not being fitted are generally considered to be a good thing as they are something (and a very expensive something) less to go wrong.
 

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