Does anyone know for certain what triggers dpf regent and what the process is?

nidgemo

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hi all - when I was buying my first e class (2008 w211) a few years ago, I got a lot of brilliant advice on here which really helped me out!

At that time I had been having a world of dpf issues in a Lexus, and was very keen to avoid the heartbreak again, which is exactly why I bought the w211 (last big prestige car not to have the f’ing things.

However, the time has come to change, and I’ve got my eye on a late 2013 w212 (facelift model).

Obviously, this WILL have a dpf in it...

So, two questions hopefully people with first hand experience will be able to help with.

First off, do these models have much in the way of dpf problems? I know it’s the nature of the internet to see lots of people with complaints but I’d welcome good and bad stories!

I DO do a lot of short journeys- leave kids to school, drive to the office, pop out for lunch, drive home, go out to the local shop etc - so I know my driving isn’t ideal, but I do love having a larger prestige car...

I know I’ll need to take if for a decent run every so often, and understand that, but that leads me to my second question...

If I’m only doing this every so often, I’d want to be sure I’m doing it right, which, for all I’ve searched, no one seems certain exactly the process...

Some say you need to be doing a regular speed for a certain period of time - if so, what speed? And for how long to complete the cycle? If you hit traffic and slow down does that cancel the regen, or reset the “time” back to zero? Some people say keep the revs high, some say drive as normal (obviously easier in an auto!)

Does the car indicate when you need to do this? A big problem in the Lexus was the first time you knew anything was up was when it told you it was blocked and went into limp mode! Does the E class tell you “dpf getting high, regen needed soon” or similar?

Really do like the car, so would really appreciate anyone with definitive knowledge or first hand experience.
 

sl500amgsport

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hi all - when I was buying my first e class (2008 w211) a few years ago, I got a lot of brilliant advice on here which really helped me out!

At that time I had been having a world of dpf issues in a Lexus, and was very keen to avoid the heartbreak again, which is exactly why I bought the w211 (last big prestige car not to have the f’ing things.

However, the time has come to change, and I’ve got my eye on a late 2013 w212 (facelift model).

Obviously, this WILL have a dpf in it...

So, two questions hopefully people with first hand experience will be able to help with.

First off, do these models have much in the way of dpf problems? I know it’s the nature of the internet to see lots of people with complaints but I’d welcome good and bad stories!

I DO do a lot of short journeys- leave kids to school, drive to the office, pop out for lunch, drive home, go out to the local shop etc - so I know my driving isn’t ideal, but I do love having a larger prestige car...

I know I’ll need to take if for a decent run every so often, and understand that, but that leads me to my second question...

If I’m only doing this every so often, I’d want to be sure I’m doing it right, which, for all I’ve searched, no one seems certain exactly the process...

Some say you need to be doing a regular speed for a certain period of time - if so, what speed? And for how long to complete the cycle? If you hit traffic and slow down does that cancel the regen, or reset the “time” back to zero? Some people say keep the revs high, some say drive as normal (obviously easier in an auto!)

Does the car indicate when you need to do this? A big problem in the Lexus was the first time you knew anything was up was when it told you it was blocked and went into limp mode! Does the E class tell you “dpf getting high, regen needed soon” or similar?

Really do like the car, so would really appreciate anyone with definitive knowledge or first hand experience.
I may be missing something here but reading your DPF history and your type of mileage shouldn't you be looking to buy a petrol version?

All diesels with no exception have DPF issues if constantly doing short trips and do you really want the inconvenience of making unnecessary 25 min trips just to clear your DPF? Also diesel are only more economical over longer runs when full operating temperature is reached. Unleaded is also cheaper at the pump and petrols cheaper to maintain and service.

As an example I recently moved from a 2.2 diesel 4x4 to a 4.7l V8 petrol 70% short runs and it is costing no more in fuel to run.

I also expect petrol versions will hold value more now that the government has decided to persecute Diesel drivers and ban some from Cities like London!

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LostKiwi

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Does the E class tell you “dpf getting high, regen needed soon” or similar?
No.
As above your driving profile is completely wrong for a diesel.

The criteria as I understand it are DPF pressure high, engine temperature normal, oil temperature normal (this can take 20 minutes), regen start.
This why a long trip is required for a regen - it takes a long time for the oil to heat up to the correct temperature (oil temps are much higher than water temps).
You can have a regen forced by using STAR or (I believe) iCarsoft MB v2.0 (as opposed to MB-II) diagnostic tools but frankly it's better to get the right technology for the job.
 

C350Carl

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DPF regen is based on the capacity of the filter and nothing else. That's why the car will force a regen regardless of other temps if it passes a set limit.

All cars with a DPF conduct two types of regen.

A passive regen is conducted when the car is driven at motorway speed and the exhaust temp is at the level required to burn off the particulates. Circa 800deg plus.

An active regen is done when the filter reaches a specified limit (usually circa 45-50%) and then fuel is injected post combustion to raise the exhaust temps. This is why if you're doing short journeys you may get out the car one day and feel a lot of heat coming from under the car and a burning smell. This is the regen taking place.

There is no warning on the dash one is taking place. I always know it's happening if I stop at a set of traffic lights as the Start/Stop will have switched itself off and the revs at idle are usually circa 1krpm rather than circa 700rpm.

The best solution for you is to change the car for a petrol given your driving habits. However as that is probably not practical especially as it would no doubt have a financial impact. Then the best thing you can do is once a week take the car on the motorway for an hour and just sit at 70mph. That will clean & regen the filter for you.

If you don't do this and you interrupt the active regen cycle then you will cause the DPF to get more and more clogged up. DPF's are circa £1500 if not more. So the few £'s in fuel to do a 1hr drive each week on a M'Way/A-Road would be a wise move.
 

sl500amgsport

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DPF regen is based on the capacity of the filter and nothing else. That's why the car will force a regen regardless of other temps if it passes a set limit.

All cars with a DPF conduct two types of regen.

A passive regen is conducted when the car is driven at motorway speed and the exhaust temp is at the level required to burn off the particulates. Circa 800deg plus.

An active regen is done when the filter reaches a specified limit (usually circa 45-50%) and then fuel is injected post combustion to raise the exhaust temps. This is why if you're doing short journeys you may get out the car one day and feel a lot of heat coming from under the car and a burning smell. This is the regen taking place.

There is no warning on the dash one is taking place. I always know it's happening if I stop at a set of traffic lights as the Start/Stop will have switched itself off and the revs at idle are usually circa 1krpm rather than circa 700rpm.

The best solution for you is to change the car for a petrol given your driving habits. However as that is probably not practical especially as it would no doubt have a financial impact. Then the best thing you can do is once a week take the car on the motorway for an hour and just sit at 70mph. That will clean & regen the filter for you.

If you don't do this and you interrupt the active regen cycle then you will cause the DPF to get more and more clogged up. DPF's are circa £1500 if not more. So the few £'s in fuel to do a 1hr drive each week on a M'Way/A-Road would be a wise move.
Good advice only the OP has not bought the car yet so your penultimate paragraph is probably the most relevant.

Most diesels I am aware of will not active regen until they have reached full operating temperature, short 1-2 mile trips are unlikely to reach the required temperature so a full DPF will not take long in those circumstances.

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C350Carl

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Good advice only the OP has not bought the car yet so your penultimate paragraph is probably the most relevant.

Most diesels I am aware of will not active regen until they have reached full operating temperature, short 1-2 mile trips are unlikely to reach the required temperature so a full DPF will not take long in those circumstances.

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Sorry, yes short 1-2mile trips wouldn’t allow the regen to take place.

However I think the car will probably still try to force it as it will try to raise the temps quicker through the process I mentioned above. It would just become an interrupted cycle which would cause more issues.
 

malcolm210

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I shared your dilemma but decided to buy diesel but only because as explained above I was prepared to make sure the car did enough 30 minute runs (minimum running time) per month to force a DPF regeneration, another contributing fact was that we get very few Mercedes DPF problems aired on the forum so that must count for something when it comes to the integrity of the MB DPF system

A couple of times a month I have to do a 15 mile journey to take my daughter to work on a Sunday morning, other than that my usage is similar to yours and this seems to keep the DPF in a healthy state but if a regen starts I do tend to try and extend that trip until the cycle has finished. If you understand engines you will get to know when a forced regen is taking place and as Carl has already said a passive regeneration goes unnoticed due to the natural high temperatures involved in the exhaust system

Hope this helps!
 

John Laidlaw

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We have an XC90 diesel which covers barely 3k miles per year - most weeks about 40 miles - as Carl has mentioned I take it once a week or 2 week maximum and borrow it for my 24 mile commute, give it a roast on the motorway - all good so far
 

flowrider

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Surely the cost of doing unnecessary 30-60 min high speed journeys every month will out way any fuel savings over getting a petrol engined car.

My ML350 diesel always had DPF issues because it would never complete a regen cycle. This is despite using the car on occasional long journeys.

My advice would be to get a petrol engined car and save any hassle and cost.
 

flowrider

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My experience is similar to sl500amgsport, i changed my ML350 diesel for a 3 litre supercharged petrol engined car and my monthly average fuel consumption is the same but petrol and servicing is cheaper.
 
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John Laidlaw

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Agreed but the XC90 is available in either a D5 diesel or a T8 hybrid petrol, the latter being stupidly expensive , so my choice was limited- I sorely wished they did a V6 or V8 petrol but no......
 

LostKiwi

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Agreed but the XC90 is available in either a D5 diesel or a T8 hybrid petrol, the latter being stupidly expensive , so my choice was limited- I sorely wished they did a V6 or V8 petrol but no......
They did a V8 and I6 up until 2010....
(and the V8 is one of the nicest I've ever heard).
 

JBell

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My C350CDi regens when needed, I do 2x 10mile journeys 4 days a week and have never had a problem.

Easy to tell when it does it as the heat soak from under the car is massive
 

John Laidlaw

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They did a V8 and I6 up until 2010....
(and the V8 is one of the nicest I've ever heard).
Yip spoilsports Alastair, the new generation just some with those 2 engines. That said the 4 pot diesel is quite willing and a nice auto box...240hp isn’t too shabby either
 

LostKiwi

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Yip spoilsports Alastair, the new generation just some with those 2 engines. That said the 4 pot diesel is quite willing and a nice auto box...240hp isn’t too shabby either
There's a supercharged and turbocharged 4 cylinder 2 litre with a very unshabby 320ps.....
 

John Laidlaw

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The T6.....
Ah I get it now....we got a Momentum (base model if you like) with a few bells and whistles added, you have to go R Design Pro and above to get the T6 engine, and that was above the ‘budget’ we’d set....
 

flowrider

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Its a shame MB don't market more petrol engine versions of their vehicles in the UK, i don't count the AMG's as they are silly money but something like a 3 litre V6 C Class SE or a 2 litre A Class, i would even have considered a 3 litre petrol V6 SUV if they did one.
 

JBell

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Its a shame MB don't market more petrol engine versions of their vehicles in the UK, i don't count the AMG's as they are silly money but something like a 3 litre V6 C Class SE or a 2 litre A Class, i would even have considered a 3 litre petrol V6 SUV if they did one.

This is the problem, you have to have a 43AMG to get a decent mid size petrol in an MB now although they do a GLC250 with a 2.0 petrol in and 211 bhp
 

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