Poor MPG on B200d W246 2016

[Kamali786]

Hi All,

It would be safe to assume im not a car know it all.. but i do know some basics.

I recently bought a 2016 model B200d amg line and one of the main reasons was due to its good mpg. They said brand new Mercedes labelled it as doing around 65mpg. The car has had 2 previous services and and one from the car supermarket where i bought it from so 3 in total. It has clocked just over 38k now and seems practically new to drive.

However..

I have now fuelled up 2 full tanks after having it around 2 weeks now and the best mpg i can get out of it has been 36! Now i can understand with the car being 4-5 years old now that expecting it to get 65mpg as advertised, it would be a bit of a stretch. But am i wrong in thinking that getting less than half means there’s something not right? Especially seeing as it has been regularly serviced, has pretty much new tyres, brakes pads changed before i bought it (so less than 3 weeks old) and it less than 5 yrs old?

Admittedly i am a penny pincher, so getting around 400miles out of a £52 full tank is killing me! (Slightly exaggerated)

I have a friend who has a 15plate C250d and is getting 55mpg on average and his bragging amongst my poor state of affairs is further enhancing my frustrations.

Am i missing something or is this normal please guys?

Any suggestions would be appreciated

 

[ajlsl600]

All makers legally lie about mpg. The only way out is to research reality mpg from owners BEFORE purchase.

 

[robin.large]

This does seem a little low however there's a lot of variables

I think MB quoted closer to 60 as new?
Depends on wheel size fitted!
Tyre pressures, make sure pressures are spot on. Also tyres juggle between grip, noise, and fuel efficiency so depends what tyres you have fitted - you can always check the tyre efficiency with something like black circles?
Driving styles and types of journey make a big difference.

As an extreme example, in cool weather, driver only, no load, motorway at 75 on cruise my CSL 63 does 28 mpg

Around town, cold starts, short journeys, city traffic, 2 people that drops to 20.


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[bertb1]

I can get 52 mpg on motorway in my c220 but on the roads over the last couple weeks I’m getting around 25/28 mpg


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[AndySlade]

I can get 52 mpg on motorway in my c220 but on the roads over the last couple weeks I’m getting around 25/28 mpg


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Check the thermostat and that the car is getting up to temperature. Diesels take a long time to warm up in colder weather.

 

[bertb1]

Where I’m working at the minute, it’s only a 9 mile journey stop starting in traffic so the car won’t be getting to full temp in this cold weather


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[DSK]

On the tyres front, on my daily driver, I went from running Goodyear Eagle Asymetric to Michelin Pilot Sport 4, in the same size and load rating, at the same pressures. (This is a car I was doing 1,000 miles A WEEK in for 5 years!). MPG dropped by 2mpg and road noise was slightly increased (despite having wheel alignment done at the same time - at our own place).

Also, do not take any stamped book or someone's word for a service as certainty. In this day and age, filters may not be addressed for some 20,000 miles even more!! Take the air filters out and see what they look like! Also do not be fooled that older engines cannot reach the claimed MPG figures. My 200,000/250,000 mile Volvo's genuinely exceed the claimed figures by around 6mpg. I get 8mpg more than the claimed figures on the 65,000mile CLS and over 90,000 miles its was 6mpg more on a new E350CDI and 8mpg more on a new Astra GTC cdti. On the Astra it was worse new, then when I'd put 90K on the clock. I'd say that this is due more to regularly checked tyre pressures, very smooth, heavily forward planned and flowing driving style, decent quality fuel and personally accounted for servicing of items.

Driving styles will play a big part in MPG differences. Additionally when I've experienced very bad MPG issues, its things like vacuum/boost pipe leaks (invisible to the eye), low tyres pressures, degraded engine mgmt sensors and poor injectors that cause massive problems.

 

[Frontstep]

Hi All,

It would be safe to assume im not a car know it all.. but i do know some basics.

I recently bought a 2016 model B200d amg line and one of the main reasons was due to its good mpg. They said brand new Mercedes labelled it as doing around 65mpg. The car has had 2 previous services and and one from the car supermarket where i bought it from so 3 in total. It has clocked just over 38k now and seems practically new to drive.

However..

I have now fuelled up 2 full tanks after having it around 2 weeks now and the best mpg i can get out of it has been 36! Now i can understand with the car being 4-5 years old now that expecting it to get 65mpg as advertised, it would be a bit of a stretch. But am i wrong in thinking that getting less than half means there’s something not right? Especially seeing as it has been regularly serviced, has pretty much new tyres, brakes pads changed before i bought it (so less than 3 weeks old) and it less than 5 yrs old?

Admittedly i am a penny pincher, so getting around 400miles out of a £52 full tank is killing me! (Slightly exaggerated)

I have a friend who has a 15plate C250d and is getting 55mpg on average and his bragging amongst my poor state of affairs is further enhancing my frustrations.

Am i missing something or is this normal please guys?

Any suggestions would be appreciated

A lot of people contribute to this;

B200 d 65.7–67.3 mpg 57.0 mpg 86%

https://www.honestjohn.co.uk/realmpg/mercedes-benz/b-class-2012

 

[Blobcat]

Cold weather kills fuel economy
Check tyres are up to pressure
Check thermostat is getting car to temp
Short journeys also kill fuel economy

 

[Wearsafoxhat]

We had an A200d (my2016) from new for a few years, don’t think we ever saw 60mpg no matter how or where we drove it.

Currently have a B180 d (my2015) and regularly see 60 or more on longer runs and still 40 around town.


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[sonic]

I have had a couple of B200d's as loan cars normally did 60mpg.
First thing to check is the brakes are not binding.
Diesel consumption does deteriorate in cold weather, a 20 miles run I do regularly returning 48-50mpg this week I only managed 43mpg.
As others have said is the engine up to temperature, it make a massive difference if it is not.

 

[ajlsl600]

Pretty sure I am averaging 50 mpg with the 170cdi which is great on a 01 diesel auto Sans all the electronic crap bolted on today
I use cruise at every chance and stick to 50,55 mph. I can put cruise in 8 mile from house and leave it there till Cherbourg 65
Mile up the road.

 

[Kamali786]

All makers legally lie about mpg. The only way out is to research reality mpg from owners BEFORE purchase.

Im aware of their dishonesty but by half should be criminal! I did extensive research and the general consensus was that it was giving around the 50mpg mark from other owners.

I think its safe to assume theres an issue somewhere

 

[Kamali786]

This does seem a little low however there's a lot of variables

I think MB quoted closer to 60 as new?
Depends on wheel size fitted!
Tyre pressures, make sure pressures are spot on. Also tyres juggle between grip, noise, and fuel efficiency so depends what tyres you have fitted - you can always check the tyre efficiency with something like black circles?
Driving styles and types of journey make a big difference.

As an extreme example, in cool weather, driver only, no load, motorway at 75 on cruise my CSL 63 does 28 mpg

Around town, cold starts, short journeys, city traffic, 2 people that drops to 20.


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Thank you for replying..

I currently have 225/45 zr18’s by Roadex. The tyre pressure recommended is 30-35psi and i have all four on 35 for further economy so i cant see it being the tyres making such an impact. I got a feeling its either the pads (which where recently changed) or they supermarket told me porkies about changing all the filters during the most recent service!

 

[Kamali786]

I can get 52 mpg on motorway in my c220 but on the roads over the last couple weeks I’m getting around 25/28 mpg


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Thats bad! What do you think is causing thag?

 

[Kamali786]

Check the thermostat and that the car is getting up to temperature. Diesels take a long time to warm up in colder weather.

Thank you..

i have been monitoring the temp which hovers around the 80-90 mark but thats after i’ve been driving it for around half hour. I assume this is normal? The temp here in the west mids has been around 4-5degrees in the nights lately but it still holds the temperature well.

I must also stipulate that its an AUTO! Forgot to mention this at the beginning, so could the auto box be a culprit in any way?

 

[Kamali786]

On the tyres front, on my daily driver, I went from running Goodyear Eagle Asymetric to Michelin Pilot Sport 4, in the same size and load rating, at the same pressures. (This is a car I was doing 1,000 miles A WEEK in for 5 years!). MPG dropped by 2mpg and road noise was slightly increased (despite having wheel alignment done at the same time - at our own place).

Also, do not take any stamped book or someone's word for a service as certainty. In this day and age, filters may not be addressed for some 20,000 miles even more!! Take the air filters out and see what they look like! Also do not be fooled that older engines cannot reach the claimed MPG figures. My 200,000/250,000 mile Volvo's genuinely exceed the claimed figures by around 6mpg. I get 8mpg more than the claimed figures on the 65,000mile CLS and over 90,000 miles its was 6mpg more on a new E350CDI and 8mpg more on a new Astra GTC cdti. On the Astra it was worse new, then when I'd put 90K on the clock. I'd say that this is due more to regularly checked tyre pressures, very smooth, heavily forward planned and flowing driving style, decent quality fuel and personally accounted for servicing of items.

Driving styles will play a big part in MPG differences. Additionally when I've experienced very bad MPG issues, its things like vacuum/boost pipe leaks (invisible to the eye), low tyres pressures, degraded engine mgmt sensors and poor injectors that cause massive problems.

Thank you for replying..

Volvo’s are a different beings when it comes to cars.. so you getting that mpg on an aged car comes as no suprise!

My dad had a 1994 Volvo 240 Estate i think it was and he done 400k on it!

I do think the issue with mine is sensors or potentially filters not being changed during a service. From everyones comments, i think it needs a once over by a reputable MB garage.

 

[V6Matty]

What type of driving are you actually doing?

 

[robin.large]

A 'once over' by MB would probably pay for a few hundred litres of fuel!
Auto box could be responsible but unlikely. Any significant slip would be noticeable, and any drag also would show up.
Brakes could be an issue worth looking at.

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[Kamali786]

Thank you all for replying. Very much appreciated.

Seems from everyones responses it could be a few things,

• Weather
• Tyres
• Filters
• Brakes
• Or bad driving

Im tortoise on the road. From behind you could easily assume its a 90yr old behind the wheel even tho im 37. Im very eco/fuel conscious and uber cautious of wreckless cretins on our midlandy roads. So defo not that!

Tyres are 225/45 ZR18’s by Roadex and they all seem to have more than enough decent tread on them. I think the supermaket i bought from said they had only done around 600miles. The pressure on them is at 35psi all round as recommended by manufacturer with basic load. Theres no tracking issues either so perhaps i can rule this one out too?

So i think its possible that its either a combination of brake and filter issues or if anything more sinister then injectors. I know garages can be a bit naughty sometimes and not change filters, and seeing that its on 38k now and probably due a fuel filter change, none of them have actually been changed. The air filter seems relatively clean, but a few youtube videos have taught me how to self clean these.

I mention brakes, as it was something the seller at the market emphasised a few times as an expensive change that they did. And im sure he said the discs were changed too.. and though i havent driven another b200, my first impressions when i drove it where that it seemed to be a little sluggish when pulling off.

Would you guys agree that some sort of health check would be a good idea? Or do i just book it in for a Major Service?

Once again thank you all for your input and advice.

PS. Its an Automatic