The 20 worst diesel cars for Real MPG

We’ve analysed 100,000 Real MPG submissions to uncover the UK’s worst diesel cars for real world fuel economy. Like the list of named and shamed petrol cars, we’ve picked the worst overall performer in the range, to avoid swamping you with dozens of versions of the same car.

Overstated fuel economy is one of the most criticised aspects of modern motoring and thousands of drivers are left out of pocket each week because of it. Thankfully Real MPG is on hand to show you how many miles a car really does to the gallon.

Listed: The petrols that fail to deliver Real MPG

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Volkswagen Golf Estate 1.6 TDI BlueMotion (2013 - ) – 53.1 per cent of official figure

With an average of just 53.1 per cent, the Golf Estate 1.6 TDI BlueMotion falls woefully short of its claimed economy. Volkswagen advertises the family estate with 80.7mpg, yet Real MPG drivers say they can’t get anywhere near this. In fact, they struggle to get little over half, with an average of just 42.8mpg. 

Read more about Volkswagen Real MPG performance


SinisterPenguin    on 9 September 2016

Judging by the number of Auto boxes I guess this tells us manufacturers are able to program Automatic gearboxes specifically for emission test <sigh>

Though who can blame manufacturers? The problem lies with the test in my opinion.

frank123    on 9 September 2016

I feel that what is even more misleading is that so many of these cars are marketed under the "eco" branding. When considering a purchase you would expect fuel consumption of a so-called eco model to be better than the non-eco model of the same car in the respective model ranges.

Are motorists simply being conned to pay extra for allegedly lower emmisions and lower fuel consumption when it looks fairly obvious that it could be simply a marketing ploy to make you part with more money in the showroom?

karenannanina    on 10 September 2016

It makes me wonder how people are driving these cars.Their economy and emissions are entirely at the mercy of their drivers, and if you drive with restraint, keeping the revs down and exploiting the low-rev torque, great economy is possible. We have had diesel cars and vans on our fleet since the mid-80s and have rarely been disappointed by their mpg. Three exceptions I can think of were the Hyundai Matrix, Toyota Avensis 2.2 and Peugeot 508, which all missed their economy targets by miles.

I was particularly startled to read that owners struggle to get mid-30s mpg from a BMW 535D. We bought a BMW Active Hybrid 5 a few months ago, which is a 3.0 litre twin-turbo petrol-engined automatic, and it gets over 37 mpg on a daily basis. How on Earth would a diesel not do better?

mintmaker    on 11 September 2016

Seems to me that most Diesel drivers, drive like its a Petrol engine, high revs, hard exceleration . Also short journeys. A few years ago dealers tried to put people off from buying Diesels if they only had short journeys. I've owned a Diesel since 2007. A Fiesta 1.6 TDCI 57 plate, av 64 mpg, a Fiesta 1.6 TDCI Econetic 02 plate av 70 mpg. Since then I've owned a Mazda CX-3 1.5 Sportnav, which av 62 mpg. Although this is nothing like official figures Diesels are far more efficient than Petrol. Also remember with any engine, the smaller engine is not always the most efficient.

misar    on 11 September 2016

Comments here and in the corresponding petrol thread that drivers are "not driving properly to get economy" are nonsense. The real world mpg database is based on tens of thousands of drivers - the results generally represent average drivers driving "averagely".

Honest John will remember days gone by when mpg was not such a big marketing deal. There were regular competitions and rallies based on achieving the lowest possible fuel consumption with standard cars. Amazing figures were achieved on very old fashioned motors using a single tankful or one gallon, just with impracticable driving methods. Any car today will do likewise if you do the same.

The point about real world mpg results is to highlight the varying discrepancies between official test results and ordinary motoring. My subjective impression is that the worst performers tend to be small diesels in small cars, eco models and some tiny turbocharged engines.

gordonbennet    on 11 September 2016

Did anyone seriously believe cars, the size and weight of some of these things, sat on huge elastic band tyres, would actually ever give 60 to 70mpg in real life, if people do believe this guff it might give some clue as to why we keep electing the politicians we do.

And has anyone watched how people, including looking at themselves, actually drive, the speeds they travel at, shifting tons of air and the total waste of their rolling mass by belting up to whatever is ahead till the very last second then jamming the brakes on...often having to come to a complete halt at junctions due to incompetent forward planning, then accelerating furiously to the next harsh brake, rinse and repeat ad infinitum.

You only have to watch an instant fuel consumption readout during acceleration to have an idea where the fuel is going.

declan88    on 20 September 2016

I seen exaactly this behaviour of bursting the car as from the gates of Hades and stopping only just in time before a junction in case they overshoot heaven. I think its partly a gun fight at the OK coral mentality which is if they look like they are not going to stop, other people will make a gap for them, rather than crash. This driving style is very common in Birmingham.

handmusic    on 12 September 2016

I do agree with those who say that it's all about the driving. During a fuel crisis when petrol was restricted I got 73 mpg out of my 1996 Nissan Micra by tailing lorries on the M1 and treating the accelerator as if it were a drain with a direct line to my bank account. My top speed was about 55mph. Normally I achieved 48 mpg in the same car.

Dr Peter B Baker    on 18 September 2016
Following positive comments from Honest John in early 2008, I purchased new a KIA Cee'd 1600 Diesel (85 BHP, Manual).
As a numbers lover I keep a log book: in 60,000 miles, actual petrol consumption has been 55.8mpg driven reasonably carefully. I have only had one set of brake shoes on the front after 7 years and one on the back after 8 years. Careful driving and use of that thing called a gearbox produces a pretty good mileage. By the way, I tend to stick to speed limits whether 30mph or 70mph.

declan88    on 20 September 2016

I think modern engines contend with a lot more than old engines did meaning that the worst engines ( ihaven't yet read the best engines/ cars for mpg) only manage 40-50mpg. Well 40mpg is what we were achieving relatively easily back in he 70s.
But then we didn'y have 4 zone air con, multiple electronic gadjets heated front windscreens, all round electrc windows and central locking and heated seats so commonly.
Also because cars were poor perfomers on the whole back then slower approaches to junctions, made for less bracking and more fluid traffic flow. Gordonbennet's observation on driving styles of the me, me, me world we live in at least explain why a greater demand on lighting the brake light and going and up and down the rev range through manic driving would lower the likelihood of achieving maximal mpg.
Finally probably out 10 years ago John Prescott talked about the successes of the Labour party i terms of "well, tha knows, that you under t'Labour Par-te, on avergae every house has 2 cars on t'drive now. So you see everybody's better off..." Indeed that did happen. And cheap loans explained why sat nat distance rather than traffic density based estimations of journey time were becoming progressively more irrelevant. These days cheap loans having been extended in car loan finance which put what would ahve been retiree or company exec cars unde rthe backside of the young turk, many young turks, further adding t traffic density.
All these things stress a cars mpg.
Lastly at in meeting just off the epi- centre ofl London (near Kings X, somewhere), I hailed taxi to get to Victoria. 40 mins later I was still in Covent Garden. I got and went and took a tube. In London at least, Uber taxis have made driving around the centre an even greater challenges. It was bedlam. And I used to live in London for 12 years up until 2011, ie pre-Uber. The traffic density is so high no emergency service could get through in good time I imagine. Try maintaining even 40mpgs in that never mind the claimed 70mpgs of some manufs.

Barsus    on 28 October 2016

Agree with many of the comments, although if the manufacturers didn't, shall we charitably say, "distort" their fuel consumption in the first place, we wouldn't be griping much at all. The Renault models listed, for example, actually were quite good, but the expectations created were just silly.

   on 9 November 2016

I know its more fashionable to find fault and knock everything, but how about listing the TOP 20, those who closely matched their advertised mpg?

HJ Editor    on 9 November 2016

You ask - we deliver.

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