Diesel big drop in consumption and smell

[Oldcolner]

My 2022 BClass AMG 2.0D auto bought in April has gIvan me great consumption figures of 65.7 on a 400 mile journey with speeds of up to 75mph in Ireland. Enjoy watching the consumption graph, but this has shown a patch where consumption dropped to 25 - 40 on the journey there and again on the way back for about 10 mins.
the car came fron a dealer 100 miles away and the day after emitted a terrible smell when stopped. Was told all diesels recharger something and not to worry. Don’t remember this with a 2013 CClass.
is this normal

 

[Blobcat]

Hello and welcome,

That will be the DPF doing a regeneration burn off

 

[ajlsl600]

Yup as above . I noticed a loss of about 4mpg since adblue delete I used to see 39 on a run 40 once now best is 35/6. Mind u if that's the price of not needing to think on that crap adblue system, so be it.

 

[malcolm E53 AMG]

Does the car get up to temperature ie 90 degrees C if the thermostat has failed open this will cause the engine to over fuel.

As above the smell is the DPF regenerating ie burning soot off filtered from the exhaust

 

[Srdl]

Welcome - sounds quite normal.

 

[Oldcolner]

Hello and welcome,

That will be the DPF doing a regeneration burn off

Many thanks
Can you advise how frequently it will do that?

 

[Oldcolner]

Does the car get up to temperature ie 90 degrees C if the thermostat has failed open this will cause the engine to over fuel.

As above the smell is the DPF regenerating ie burning soot off filtered from the exhaust

Thanks
No problem with temperatures

 

[Oldcolner]

Yup as above . I noticed a loss of about 4mpg since adblue delete I used to see 39 on a run 40 once now best is 35/6. Mind u if that's the price of not needing to think on that crap adblue system, so be it.

Thanks
Mine has adblue which I’m told only needs topping up when serviced. Also has a boot battery which the car said had given me 100 bonus miles on a 400 mile trip. Still getting used to the vast number of features. Only just linked to Mercedes me after 2 months!

 

[Blobcat]

Many thanks
Can you advise how frequently it will do that?

Depends very much on driving profile - many hours on the motorway and very infrequent. Lots of short town driving and much more often

 

[V6Matty]

The car will regen ~ every 300 miles, but does depend on how it’s driven, if you often do short journeys then it’ll fill quicker and therefore regen more often.
Re the adblue, you may get away with just topping up at service but in reality you’ll likely have to top up yourself, the car will warn you though that it needs more. This said, adblue does go off quickly and crystallises, there are now a few manufacturers of an additive to put in with adblue to help if from crystallising

 

[Oldcolner]

Depends very much on driving profile - many hours on the motorway and very infrequent. Lots of short town driving and much more often

Thanks again bobcat. More likely to be short but just done 1000 in a week and it regenerated twice approx 500 miles apart. Surprised how low consumption fell having been 50 - 66 for hours it was down between 30 -40 for 10 mins or so then returned.

 

[Oldcolner]

The car will regen ~ every 300 miles, but does depend on how it’s driven, if you often do short journeys then it’ll fill quicker and therefore regen more often.
Re the adblue, you may get away with just topping up at service but in reality you’ll likely have to top up yourself, the car will warn you though that it needs more. This said, adblue does go off quickly and crystallises, there are now a few manufacturers of an additive to put in with adblue to help if from crystallising

Thanks Matty ad blue is a new thing for me. Does use go up with mileage as I’ll probably not be doing a lot.

 

[sonic]

When you are in region mode the idle revs are higher about 1,000 RPM.
On my E350CDI the exhaust note changes.

 

[V6Matty]

Thanks Matty ad blue is a new thing for me. Does use go up with mileage as I’ll probably not be doing a lot.

Yep the more the use the car especially if short journeys the usage will go up, that said it’s easy enough to buy and refil yourself these days, local petrol station to me have even just installed an adblue pump in the forecourt and no longer sell the small bolted of the stuff

 

[Oldcolner]

Thanks everybody