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Main road Mercedes motoring

Mactech

MB Enthusiast
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Joined
Dec 19, 2005
Messages
5,603
Location
Norfolk
Car
Bentley Bentayga D V8, BMW i3
Since my wife’s ML has been with the dealers on and off to try to resolve the Airmatic issue, we have had the opportunity to sample quite a few diesel autos in the Mercedes range as loan cars. I tend to travel light, so to avoid swapping stuff from one car to another I have used the loan cars (all just a few months old) and my wife has defaulted to my S.
Most of my journeys are out of town and at least 100miles long and mostly on trunk roads, dual carriage way or motorways. Average speed is normally 55 to 60mph cruising at 70(ish) where legal. I know this does not fit the same profile as most peoples use, but at least it is a constant with the same driver driving in the same (sympathetic?) way, along similar roads.

Car Cost (nearly new)/ Off. Ex.urban /Actual MPG
S320 CDI (Modified)/ £45k/ 47.9/ 46.5
CLS 320 CDI/ £35K / 47.9/ 44.4
E220 CDI / £22k/ 52.3/ 46.5
CLC 220 CDI/ £18K / 54.3/ 47.2
A160 CDI/ £14k/ 60.1/ 52.6
ML 320 CDI/ £35k/ 35.8/ 35.4

The surprise to me is that with the exception of the ML (4WD and town hall aerodynamics) and the A Class (plan your overtakes with a calendar) all the cars use pretty much the same amount of fuel! This may not be the case in town, but on the open road the difference is not great.
The S Class is simply the most stress free way to get around by road. The ability to glide up to 800 miles between refuelling is fabulous.
The CLS is a wonderful looking car, smooth, quiet and powerful but just fails to match the serenity of the S.
The E220 is possibly a nicer place to be than the CLS. I prefer the interior and the latest 4 cylinder diesel is a big step forward from the E220 I had in 05. It’s very responsive and only ever feels out of its depth during extreme overtakes. The refinement and power are not quite in the 320 league, but a lot closer than before. It still looks like a taxi, but sounds much less like one! I was surprised that it seems only a smidge more frugal than the 320.
The CLC shows the age of its platform. Not a bad little car but the hard seats and ride and a very lethargic auto ‘box means it is not the best long distance cruiser.
The A class is not really in its element on the open road. A perfectly acceptable and spacious way of getting around, just don’t try to overtake anything! A much better urban car.
The ML (with suspension!) is a remarkably capable long distance cruiser. The elevated position is good for visibility and comfort and once up to speed the cabin refinement is very relaxed.
Again this clearly demonstrates that the cost of running a Mercedes is not really in the cost of fuel, but in the deprecation of which ever model you feel suits your needs best.
And that is largely dictated by the purchase price.
 
Hi Mac,

How the hell do you get 35.4 mpg out of the ML 320CDi?

Over 30,000 miles my average mpg is 27.5 (measured not computer value) and with a following wind I've only twice got 32 mpg (computed) on a run. A goodly proportion of my driving is on dual carriageways @ 70 mph (with c.control on). Even on a long run (Scotland return from Kent) I only averaged 30.5 and MB only claim 30 mpg combined.

Cheers,
 
Hi Mac,

How the hell do you get 35.4 mpg out of the ML 320CDi?

Over 30,000 miles my average mpg is 27.5 (measured not computer value) and with a following wind I've only twice got 32 mpg (computed) on a run. A goodly proportion of my driving is on dual carriageways @ 70 mph (with c.control on). Even on a long run (Scotland return from Kent) I only averaged 30.5 and MB only claim 30 mpg combined.

Cheers,
I agree with you. In neither the ML270cdi nor in the ML 320cdi could I get much over 30 mpg on a run.
On my S class if you were careful you could get 35-37 mpg on a run.
On the A180cdi CVT auto we regularly got 52 mpg on a run.
With the E 220cdi we get low forties on a run. In my experieice they all offer close to the MB claimed 'combined' figure when on a run.

One of the problems with comparisons, of course, is that with most drivers if you give them less power than they are used to, they use the right foot more to compensate.

The second problem is that few check the computer readings by doing thorough tankful to tankful tests. When they changed the instrument cluster on my S class the second one gave very different mpg readings compared with the first. So much so I took it back and they reset it.

My brother has an A160cdi manual and regularly returns around 65 mpg on a run, measured tankful to tankful.
 
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Average speed is normally 55 to 60mph cruising at 70(ish) where legal.
The average speed for the extra-urban test cycle is only 39 mph, btw. So your figures should be lower ... which they are, although only just in the case of the ML. That one result does look a bit strange IMO.
 
hawk20-an E220cdi can easily do 50mpg on a gentle A road run. Try and match the 55mpg extra urban figure, thats tougher but the combined one is easy to beat.
 
hawk20-an E220cdi can easily do 50mpg on a gentle A road run. Try and match the 55mpg extra urban figure, thats tougher but the combined one is easy to beat.
I'm talking in the estate and so far only in winter and with a tight new engine. Summer comes and now reached 13k miles so should get better.

BTW you won't get 50 plus mpg from an estate as even the govt test on extra urban only gets 47.9 and that is at an average of under 40 mph. The combined figure is 38.7 for the automatic estate and 42.2 for the automatic saloon.
 
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I'm talking in the estate and so far only in winter and with a tight new engine. Summer comes and now reached 13k miles so should get better.

Aye, but yours is the new improved engine so there is an advantage. However you won't really feel the MPG difference until the car has done 40k miles plus. Someone on the other place has had 63mpg out of a 211 220cdi and I am still 10mpg short. Must be all the hills around here but they do make nice views :D
 
Aye, but yours is the new improved engine so there is an advantage. However you won't really feel the MPG difference until the car has done 40k miles plus. Someone on the other place has had 63mpg out of a 211 220cdi and I am still 10mpg short. Must be all the hills around here but they do make nice views :D
Wow! That is some target to beat! I agree more miles certainly improves mpg. So does summer.
 
The average speed for the extra-urban test cycle is only 39 mph, btw. So your figures should be lower ... which they are, although only just in the case of the ML. That one result does look a bit strange IMO.

My main road motoring contains much less accel and braking than the official extra urban test method. The average speed is higher which means aerodynamics rather than weight have more influence on the final figure.
The ML and S Class are verified figures, but for the loan cars I have had to rely on the dash readings.
The best I have had from the ML is 43mpg, and the figure I have used is what I have recorded on main road journeys. My wife has only got 28mpg over the last few months with her commute into the city.
 
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Our Vito has the same 3.0 V6 CDI engine (in a state of tune somewhere between "280" and "320"), with the 5-speed auto box. It's lighter than an ML but possibly has a little more aerodynamic drag. On a long run it will just reach 31 mpg now (11k miles on the clock), cruising at 70 mph. Average consumption is around 24 mpg.
 
BTW you won't get 50 plus mpg from an estate as even the govt test on extra urban only gets 47.9 and that is at an average of under 40 mph. The combined figure is 38.7 for the automatic estate and 42.2 for the automatic saloon.

This will be exception that proves the rules then! 2005 E220 Estate in winter!
I admit I was trying!
 
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Even in summer with a more bedded in car thats not do-able up here due to the hills etc.

Did you over inflate your tyres. I run mine 3psi higher than recommended @ front and 5psi higher (than is recommended for 5 passangers + luggage). This helps but am well short at 53mpg.

Was the car mapped differently, areo enhanced etc
 
Even in summer with a more bedded in car thats not do-able up here due to the hills etc.

Did you over inflate your tyres. I run mine 3psi higher than recommended @ front and 5psi higher (than is recommended for 5 passangers + luggage). This helps but am well short at 53mpg.

Was the car mapped differently, areo enhanced etc

Norfolk seems to have far more Police than mountain rescue people:eek:
The car was standard at the time but there was a (literally) a following wind on that day. The higher pressures seems to work on the 19 and 20" rims on the S class, but I saw little change on 16" rims on the E.
 

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