2013 S212 E220. Is my fuel economy low?

2013 S212 E220. Is my fuel economy low?

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HaplessBoyLard

Original Poster:

1,561 posts

193 months

Thursday 7th May 2020
quotequote all
I’ve tried to work out if my economy is low, but trying to sift through various sources of info makes it no clearer. Hopefully someone here with a bit of real world experience can put my mind at ease.

Yesterday I drove from Heathrow to Norfolk. 140 miles. The roads were obviously as quiet as you’d ever see them. M4, M25, M/A11 and approx 8 miles of rural roads to my house. Wherever possible I had the cruise set to an indicated 75-77mph. Nothing faster than that all the way home.

The OBC told me 45 mpg. I haven’t always paid that much attention to the economy figures but I feel like this is a fair bit lower than it would have been when I got the car almost 3 years ago.

115k on the clock. Always serviced on time with a great Indy garage (Merc Pro in Wymondham, if you’re local). It’s been really reliable so far...The only issues I’ve had were a blocked DPF due to a failed sensor not regenerating the filter and a gummed up fuel filter that caused a fuel pressure code. Both quickly and cheaply fixed.

Is that figure less than you would expect? Obviously it’s not terrible (though probably not actually accurate), but would appreciate your opinions on whether there might be something wrong.

Is there anything common on these engines that would cause a drop in economy?



Edited by HaplessBoyLard on Thursday 7th May 16:05

quinny100

954 posts

191 months

Thursday 7th May 2020
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It's not really low enough to suggest there is something definitely wrong.

Did you have passengers or luggage on board?

Cruising at 70 rather than 77 would have given you another 3-4MPG.

The 8 miles on rural roads could have killed the economy if you were driving with a heavy foot.

The economy on my S213 E220d seemed to have dropped off - I do a regular long trip to a customer and when I first got the car I would get 55-57MPG for the trip. Now it's more like 50-52MPG. I've worked out it's more that likely due to the completion of certain sections of the smart motorway works on the M6 where I would previously have been cruising at 50MPH due to the average speed cameras are now covered at 70MPH.

Sheepshanks

34,255 posts

124 months

Thursday 7th May 2020
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Is the MPG just the home trip or is it also registering a prior journey?

I've got an older C Class - C270CDi estate - and I pretty well only use it for a couple of long motorway journeys down south from the north-west per month. Generally cruise control at 75. I can nudge mid-50's MPG in an absolutely ideal journey, but it only takes the slightest thing and it'll be under 50. If I do the journey at indicated 80 it'll be low 40's.

On the MB forums though, you do get peope who post up snaps of the most amazing MPG figures - sometimes at pretty decent average speeds. Most odd.

Mr E

22,034 posts

264 months

Thursday 7th May 2020
quotequote all
Sheepshanks said:
On the MB forums though, you do get peope who post up snaps of the most amazing MPG figures - sometimes at pretty decent average speeds. Most odd.
I’ve seen 30mpg. Like, twice... smile

HaplessBoyLard

Original Poster:

1,561 posts

193 months

Thursday 7th May 2020
quotequote all
quinny100 said:
It's not really low enough to suggest there is something definitely wrong.

Did you have passengers or luggage on board?

Cruising at 70 rather than 77 would have given you another 3-4MPG.

The 8 miles on rural roads could have killed the economy if you were driving with a heavy foot.

The economy on my S213 E220d seemed to have dropped off - I do a regular long trip to a customer and when I first got the car I would get 55-57MPG for the trip. Now it's more like 50-52MPG. I've worked out it's more that likely due to the completion of certain sections of the smart motorway works on the M6 where I would previously have been cruising at 50MPH due to the average speed cameras are now covered at 70MPH.
That’s sort of where I am with it. It’s not disastrous, but it’s giving me this nagging feeling that something might be wrong with it.

It was just me in the car with a couple of small bags. A while back I did Norwich to St Ives (Cornwall) with me, the Mrs, my mum and her friend, 3 suitcases, golf clubs and a spaniel, and the car did 52mpg over the 420 miles. All 60 mph A road once in Cornwall, more or less, but it’s journeys like that give me my suspicions.

I’m doing the journey weekly at the moment, so I’m going to try a 70mph run and see what difference it makes. The rural section I just cruised. No heavy foot there.

Sheepshanks said:
Is the MPG just the home trip or is it also registering a prior journey?
No. Admittedly I was only in work for about 3 hours on Wednesday morning before heading back to Norfolk, but I reset before leaving LHR.

It’s been a bit sporadic for a while. I was working at Gatwick until a few weeks ago and the journey back on a Thursday lunch time along the M25 and A12 I’d usually get 50mpg or thereabouts at similar speeds, but with much more slowing down because the lorries on the A12 like Elephant racing.

Before that I was in Cirencester for most of last year and on a Friday lunchtime I’d usually get the same 50 odd mpg.

How much does temperature play a part on these cars? The journey down to wherever I am n a Sunday night always seems worse.




yellowbentines

5,506 posts

212 months

Thursday 7th May 2020
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I had a 2013 S212 E220cdi, covered about 40k miles in it. From memory the OBC showed a long term average of 43mpg.

I'd nudge over 50mpg if I was driving at 50/55mph on the motorway through roadworks for example, but 45-48mpg was the norm for a long journey at 70-75mph.

I always thought I got slightly worse economy when using cruise control.

HaplessBoyLard

Original Poster:

1,561 posts

193 months

Thursday 7th May 2020
quotequote all
yellowbentines said:
I had a 2013 S212 E220cdi, covered about 40k miles in it. From memory the OBC showed a long term average of 43mpg.

I'd nudge over 50mpg if I was driving at 50/55mph on the motorway through roadworks for example, but 45-48mpg was the norm for a long journey at 70-75mph.

I always thought I got slightly worse economy when using cruise control.
Interesting, thanks. I’ve done 44k in mine since I got it and haven’t reset the cumulative odometer for almost 40k. The average is 44.8 mpg.

HaplessBoyLard

Original Poster:

1,561 posts

193 months

Thursday 7th May 2020
quotequote all
Oh....one other thing.

I’d been away from work for a while due to Covid, and while the car sat at home the battery died a couple of times. The car needed a booster both times to get it started.

I’ve also noticed the ECO hasn’t gone green very often recently.

Anything in that?

928

221 posts

182 months

Thursday 7th May 2020
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Is it just the dash reading or brim to brim calculations? It could be the calculated has gone a bit awry.

Tyres, tyre pressures? Tracking? Maybe the alternator is working harder but should really charge a battery easily in that journey. A/C working harder now it is warmer?

For reference my '03 E270 manages a real 40-42 in that sort of driving, 70-80 cruise usual traffic, doesn't really improve with zero traffic unless speed is reduced. Recent trips with an end of life battery, although never actually flat, kept to those figures.

HaplessBoyLard

Original Poster:

1,561 posts

193 months

Thursday 7th May 2020
quotequote all
928 said:
Is it just the dash reading or brim to brim calculations? It could be the calculated has gone a bit awry.

Tyres, tyre pressures? Tracking? Maybe the alternator is working harder but should really charge a battery easily in that journey. A/C working harder now it is warmer?

For reference my '03 E270 manages a real 40-42 in that sort of driving, 70-80 cruise usual traffic, doesn't really improve with zero traffic unless speed is reduced. Recent trips with an end of life battery, although never actually flat, kept to those figures.
It’s the dash reading, hence my comment about accuracy in the OP.

New, decent quality tyres all round. The toe adjustment is slightly out but has been that way ever since I changed the tyres a while back. One of the old tyres was causing a pull but I’d had the suspension adjusted not knowing that. Once the tyres were changed it was obvious something was wrong with the old tyres. It’s not that though. These tyres have been on a while and it’s really only the steering wheel that’s misaligned. Everything else is fine.

Pressures recently checked. I switched the AC off and it seemed to make no noticeable difference.

Tony1963

5,155 posts

167 months

Thursday 7th May 2020
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One thing that hasn’t been mentioned yet is wind direction. For the last couple of weeks the wind has been from the north east ish. That means you might have been heading right into it heading towards Norfolk. That could easily explain the slight drop in mpg.

HaplessBoyLard

Original Poster:

1,561 posts

193 months

Friday 8th May 2020
quotequote all
Good point on the wind, but if that was causing it and the wind has been the same for a while, I’d expect the journey down there to have been a bit better and it wasn’t.

I’ve seen it make a Massive difference though. I did Lincoln to Norwich at an indicated 58 mpg with a strong westerly wind helping all the way.

HocusPocus

1,054 posts

106 months

Friday 8th May 2020
quotequote all
I must be doing it all wrong. My w204 C63 estate struggles to get 18mpg in all conditions, irrespective of following wind strength or labrador in the boot.

Although I did manage this in a 1.4 dsg petrol Golf last year.


Edited by HocusPocus on Friday 8th May 21:39

evojam

614 posts

165 months

Saturday 9th May 2020
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HocusPocus said:
I must be doing it all wrong. My w204 C63 estate struggles to get 18mpg in all conditions, irrespective of following wind strength or labrador in the boot.

Although I did manage this in a 1.4 dsg petrol Golf last year.


Edited by HocusPocus on Friday 8th May 21:39
Good old VAG 'feel good' trip computers upto there old tricks again!



HocusPocus

1,054 posts

106 months

Saturday 9th May 2020
quotequote all
evojam said:
HocusPocus said:
I must be doing it all wrong. My w204 C63 estate struggles to get 18mpg in all conditions, irrespective of following wind strength or labrador in the boot.

Although I did manage this in a 1.4 dsg petrol Golf last year.


Edited by HocusPocus on Friday 8th May 21:39
Good old VAG 'feel good' trip computers upto there old tricks again!
Accurate trip computer, as later 800km of that same 11h 45m drive came out just over 40mpg. Just 30km of delicate right foot maestro wizardry

Tony1963

5,155 posts

167 months

Saturday 9th May 2020
quotequote all
HaplessBoyLard said:
Good point on the wind, but if that was causing it and the wind has been the same for a while, I’d expect the journey down there to have been a bit better and it wasn’t.

I’ve seen it make a Massive difference though. I did Lincoln to Norwich at an indicated 58 mpg with a strong westerly wind helping all the way.
Quite often the wind is stronger in the afternoon.

For years I travelled on the A14 from Noomarkit to Slowmarket, and the difference was sometimes as much as 10mpg at 70mph.

sunbeam alpine

7,042 posts

193 months

Saturday 9th May 2020
quotequote all
Might be worth brimming the tank and calculating it that way.

I don't have a Mercedes but my fuel economy is always better than what the OBC would have me believe...

Deano_BMW

430 posts

191 months

Wednesday 20th May 2020
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for what its worth OP, i have a S205 250. driving at similar speeds mine will do 43-45mpg on the OBC but a couple more when calculated. Thats doing 200 miles on very very quiet roads because of the time i travel, all at motorway speeds.
Id maybe expect youirs to be a couple of MPG better. have you checked your tyre pressures are ok etc?