Any effect on AdBlue on DPF Regeneration in a MB?
Thread Starter
Senior Member
Joined: Apr 2016
Posts: 266
Likes: 20
From: Australia
GLC 250D
Any effect on AdBlue on DPF Regeneration in a MB?
At the beginning of the year I took delivery of my first MB and first diesel - a GLC 250D.
My initial plan wasn't to get a diesel, as I wasn't convinced that my driving pattern was adequate to keep the filter clean. Close perhaps at times, but less so at other times. But the only vehicle available that met my requirements without a custom order was this diesel.
Pre-purchase, the salesperson at my local dealer pretty much said that AdBlue / Bluetec etc means that having to do lots of highway miles to keep the filter clean is no longer an issue. But post-purchase that's not what the manuals and documentation say. You still need to exercise the car regularly it would seem.
So my question as a diesel newbie is: Is AdBlue / Bluetec just about emissions reduction, or does it assist in the regeneration process? What do I believe: what I was told or what I have read?
I've tried quite hard to research this, but haven't found a clear answer. I got the impression that in other makes, AdBlue is injected after the DPF which would imply it's only about NO2 reduction. But I also gained the impression that the MB Bluetec system is structured differently, and perhaps there is an effect.
Apologies if this is a common question, but I haven't found the answer.
My initial plan wasn't to get a diesel, as I wasn't convinced that my driving pattern was adequate to keep the filter clean. Close perhaps at times, but less so at other times. But the only vehicle available that met my requirements without a custom order was this diesel.
Pre-purchase, the salesperson at my local dealer pretty much said that AdBlue / Bluetec etc means that having to do lots of highway miles to keep the filter clean is no longer an issue. But post-purchase that's not what the manuals and documentation say. You still need to exercise the car regularly it would seem.
So my question as a diesel newbie is: Is AdBlue / Bluetec just about emissions reduction, or does it assist in the regeneration process? What do I believe: what I was told or what I have read?
I've tried quite hard to research this, but haven't found a clear answer. I got the impression that in other makes, AdBlue is injected after the DPF which would imply it's only about NO2 reduction. But I also gained the impression that the MB Bluetec system is structured differently, and perhaps there is an effect.
Apologies if this is a common question, but I haven't found the answer.
Thread Starter
Senior Member
Joined: Apr 2016
Posts: 266
Likes: 20
From: Australia
GLC 250D
Thanks for the link. FYI, I'm in Australia, not the US.
As I said, I had done a fair bit of research on this topic to get myself up to speed (so to speak) before asking the question. I had seen that link and many more like it. As I understand it, the MB Bluetec + AdBlue system operates a bit like this:
Diesel Oxidation Catalyst + DPF -> Adblue Injection -> Selective Catalytic Reduction
I read a reference that said that MB puts the DOC and DPF in the same housing, although that doesn't seem to change the answer to my question. If I've got this right, then I don't see that AdBlue can make any difference to regeneration of the DPF, as it's added in later.
So was my dealer wrong? Well, further research indicates that AdBlue means that there's no need for NOx-regeneration by causing the engine to generate rich exhaust gas. It's possible that he was referring to that, but wasn't very specific.
But it remains the case that I was told that there was no need to worry about the filters with AdBlue, and it seems that's only partly true. I will still need to get the car up to operating temperature for long enough on a regular basis to enable passive regeneration of the DPF? Which is what I was hoping to avoid.
Have I got this right?
As I said, I had done a fair bit of research on this topic to get myself up to speed (so to speak) before asking the question. I had seen that link and many more like it. As I understand it, the MB Bluetec + AdBlue system operates a bit like this:
Diesel Oxidation Catalyst + DPF -> Adblue Injection -> Selective Catalytic Reduction
I read a reference that said that MB puts the DOC and DPF in the same housing, although that doesn't seem to change the answer to my question. If I've got this right, then I don't see that AdBlue can make any difference to regeneration of the DPF, as it's added in later.
So was my dealer wrong? Well, further research indicates that AdBlue means that there's no need for NOx-regeneration by causing the engine to generate rich exhaust gas. It's possible that he was referring to that, but wasn't very specific.
But it remains the case that I was told that there was no need to worry about the filters with AdBlue, and it seems that's only partly true. I will still need to get the car up to operating temperature for long enough on a regular basis to enable passive regeneration of the DPF? Which is what I was hoping to avoid.
Have I got this right?
Senior Member
Joined: Jun 2011
Posts: 392
Likes: 16
GLE 300d (v167)
Did you ever get an answer on this?
I’m curious too as an Aussie owner, because I had an older w204 C250 CDI which had a DPF warning lamp come on if you hadn’t been driving the car sufficiently but then on my new w205 C250d I don’t recall there being a lamp. It also had Adblue (unlike my previous car) so I wondered if that helped. I’d imagine my w205 is similar to Op’s GLC250d (they all have same OM651 2.1L diesel engine too).
I now now have a v167 GLE300d with the newer 2L Diesel engine but I don’t remember seeing a warning light either when I skimmed the manual.
I’m curious too as an Aussie owner, because I had an older w204 C250 CDI which had a DPF warning lamp come on if you hadn’t been driving the car sufficiently but then on my new w205 C250d I don’t recall there being a lamp. It also had Adblue (unlike my previous car) so I wondered if that helped. I’d imagine my w205 is similar to Op’s GLC250d (they all have same OM651 2.1L diesel engine too).
I now now have a v167 GLE300d with the newer 2L Diesel engine but I don’t remember seeing a warning light either when I skimmed the manual.
Last edited by JaCe88; Aug 19, 2019 at 08:56 PM. Reason: Aussie
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,225
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
In 3 years since the question lot of new info come to the net.
Right now ScanGauge makes gauges who will tell when DPF regeneration happens, so you can avoid main problem, what is shutting the engine off during regeneration.
AddBlue is past DPF and has no effect how DPF works.
Right now ScanGauge makes gauges who will tell when DPF regeneration happens, so you can avoid main problem, what is shutting the engine off during regeneration.
AddBlue is past DPF and has no effect how DPF works.
