News : Which? confirms hidden costs of running diesels

Which? has confirmed that the running costs of diesel cars can often outweigh their economy benefits, particularly after the cars pass three years old. Despite superior fuel economy and usually lower car tax, a Which? investigation has found that new diesel cars are often more expensive to run than petrol cars.

This year is set to be the first in which diesel cars will make up more than half the new car market. However, a Which? comparison of diesel and petrol versions of six popular car models has found that even when the cars are new, petrol engines can be the more cost effective choice for drivers covering a typical annual mileage. Diesel engines may deliver cheaper fuel bills than their petrol counterparts initially but it takes many years before they actually save the average driver1 money.

With drivers having to pay a premium for a diesel car, typically £1000-2000 more on a new car, Which? tests reveal that it could take up to 14 years to recoup the upfront costs in fuel savings. Lower pump prices for petrol and improvements in petrol engine economy mean that petrol cars now often provide better value for money.

The biggest mistake of all is to buy a high mileage three-year-old ex-fleet diesel car on the false assumption that diesel engines are robust enough to take the mileage and continue to offer fuel economy advantages. All too often, dual mass flywheels,  diesel particulate filters, EGRs and turbos fail, potentially landing the car buyer with bills greater than the vale of the car.

Which?’s own fuel-economy tests also often fell short of the manufacturers’ claims for both diesel and petrol cars, meaning that motorists shouldn’t place their faith in official miles per gallon (mpg) figures. The Which? study also considered reliability, taking information directly from the 2012 Which? Car Survey, which found that petrol cars are generally more reliable than diesels – both in the first three years of their life (the typical warranty period), and even more so between four and eight years-old.

[Source Honest John]

Keith Adams


  1. I completely agree with the comment about making the mistake that a high-mileage Diesel car is a good buy – in my case it most definitely wasn’t – the car cost £4k to repair, and was eventually sold a year later, after nothing but problems, for £1800! I’ve replaced my car twice since then (I have a company car now), and I’m still paying off the garage bills. However, given the mileage I cover, purely from the point of view of cost of fuel, Diesel is still the best solution for me. But, developments like FIAT’s TwinAir and Ford’s low capacity petrol turbo engines may start the beginning of the end for Diesel engines for the average motorist.

  2. I have said this all along,high mileage or not,once on the second hand car market,who is going to afford a two grand DPF on an audi once out of warranty?oh,and the likes 0f the 1.0 ecoboost have to last as well-already in the B/C MAX,they will be shagged,always on boost always working for a living.

  3. The trouble is, these 1.0 so called eco boost engines are turbocharged to within an inch of their lives, and will have quite a high failure rate, when you think of how much power they have, and how much weight they have to pull around. This happened with buses & trucks, they went for smaller capacity engines to save weight,and turbocharged them insanely, but in the end, they found they had a very short lifespan, and now have switched to larger capacity units once more. Volvo replaced the 7 litre unit with a 9 litre in double decks and light coaches, and the heavyweights now have a 13 litre unit.

  4. @3 Surely you can’t be applying the principals of a constantly in use commercial vehicle to a passenger vehicle?

    Technology has moved on a long way from simply throwing turbo on an otherwise standard petrol engine as the Japanese did in the 80’s.

    Even if the smaller engined Ford or Fiat units are on the limit and being used as fleet vehicles (unlikely), there are still far fewer expensive components to blow up.

    Diesel is dead – good riddance as it’s filthy, dangerous stuff anyway.

  5. The problems with diesels started when they tried (and more or less succeeded) to bring the performance up to petrol engine equivalents.
    Yes, diesels used to be noisy and smoky and heavy and slow and…but pre-turbo they used to run forever on very little and were virtually unbreakable.
    Most of the ‘faults’ could be designed out without resorting to the highly stressed technological ‘marvels’ now considered essential.
    For high mileages you can’t beat a largish diesel chuntering away with loads of torque at low revs.
    You want performance? Stick with petrol.

  6. There are diesels and there are diesels.

    I once had a very cheap non-turbo Fiesta Classic diesel (the run-out Mk3 model minus the anti-roll bars which it didn’t need anyway) and that came to me with 136000 miles on the clock, and served me well for over two years.

    It was considerably faster than it had any right to be (no waiting for the turbo to come on song) and the only thing I replaced on it before the cam belt broke were normal service items (filters, etc) and the glow plugs. Oh, and the heavy iron-weighted rubber-bushed thingamyjig that attached the accellerator cable to the engine used to keep slipping off, until I drilled a hole in the end of the arm and inserted a bent split pin in it to stop it.

    ‘Old skool’ Ford diesels often get mocked, especially in these pages, but I am a fan. Simplicity, durability, economy and sufficient power (in a Fiesta anyway) meant it was an excellent, if a little unrefined, engine for the purpose, and might still have been going now had I had the funds to get the cam belt sorted. It also managed to handle well, albeit the controls and steering were rather heavy.

    Newer diesels? Not so sure about. I’ve heard lots of tales of woe. I wonder if the demands of increasingly stringent Euro emissions requirements, plus the need to keep upping the ante re horsepower to make them more palatable for petrol afficionadoes is outstripping manufacturers ability to engineer in durability.

    As for diesels being ‘filthy’ I don’t agree. Certainly older ones may have been, but they have the ability to run on recycled cooking oil based biodiesel, which is probably the greenest fuel going for the moment, and tend to be cleaner running on it.

  7. @4 ford with the ecoboost wont give a 7 year warranty like kia does with any of its cars-chiefly because they lead the market fleet wise to a point and after three years of fleet they couldnt care less,this engine sits on a piece of A4 paper it is that small,these cars are already on order for our fleet-some 1500 focus models to begin with,and i guarantee they will be goosed after two years,the failure rate will be interesting,also hearts and minds have to be won over,the 3 pot eco boost is quite smooth due to having an imbalanced flywheel to cancel out second order vibration,128 BHP out of a 1 litre? what about 500 BHP from 2 litres-both questions have the same answer-are they going to last?

  8. @6 an old p reg a4 may run on chip fat but new stuff wont,especially with fuel quality sensors fitted,if you do kiss pump and injectors goodbye.

  9. @6 lots of valid comments and our 1.8 diesel Escort shop van was great fun as I recall, and pretty indestructable.

    Doesn’t change the fact that diesel oil is nasty and the emissions are now proven to be very dangerous to health, far more so than petrol.

    Bad news for us as all the high-mileage, badly serviced chuggers hit the second hand market, and bad news for unsuspecting owners duped into buying them.

    Of course, I’m with you the day we can buy recycled cooking oil based biodiesel at the pumps. Until then, it is simply horrible stuff.

  10. @7 Yes fair enough, I can see the point regarding the warranty, but Ford and Fiat have a lot riding on the reliability of these engines as they’re being rolled out pretty much across the range in various forms.

    Reading the technical specifications, there seems to be a lot more than a mild workover going on to extract such power and torque out of these little units, and the reviews have been extremely favourable. Surely siginificant testing (accepting it can’t reflect real life precisely) will also have taken place?

    My comment was that the scenario comparison of a bus (presumably) doing hundreds of thousands of constant ‘start-stop’ miles versus an average mileage Fiesta or Focus is perhaps a little unfair.

  11. @9 John G,

    You can buy recylcled chip fat biodiesel from a pump- just not in mainstream garages. Usually you have to go to some corner of an industrial estate. There are a few people who do the rounds collecting from fast food places, etc, then process it into biodiesel.

    Of course, not only do they tend to be ‘off the beaten track’ but they may not be in when you call round to fill up.

    And of course if everybody bought recycled chip fat biodiesel there would not be enough to go round (at least in England- Scotland maybe!).

  12. The problem with the Which report is it ignores the higher resale value of diesel and other benefits such as better towing for caravans etc. ANY high mileage ex fleet car will have potential high costs whether petrol OR diesel. I have an audi a2 with 115k miles i bought with 28k miles and hasn’t cost anything beyond servicing and cambelt change. We bought a SEAT Toledo 2.0TDi last year with 100k on the clock and FDSH and still runs like a dream 13k miles later. DMF’s are also fitted to petrol cars and no one yet knows how the small turbo’d petrol engines will cope when 5 years old with 100k miles on the clock….. Also the small Fiat engine simply doesn’t deliver anywhere near the claimed economy in real world use. As for particulates, do not think only diesels are responsible, people do not seem to realise petrol also roduces much finer particulates which are potentially more hazardous to health. When someone proves to me there is a small light petrol engined car that will match the real world day-to-day 60+ mpg of my A2 then i will look at it.

  13. @12, Adrian888,

    The Audi A2 diesel is also an interesting driver’s car- in some ways not that well developed (much like my then A4), the ESP is over-intrusive, but the car has tremendous character thanks to a bubbly 3 cylinder diesel (sounds a bit like a Scania V8 in miniature) delivering astonishing accelleration (up until the rev limiter cuts in unexpectedly).

    The A2 was a car before its time- it would surely have benefitted from the DSG gearbox more than any other VAG-based car.

  14. I agree to a point of this recent study, back in the early 90s we had 88 Fiesta 1.6D and 87 1.6 petrol Orion, In town there was a huge mpg difference between them, (Fiesta 60+, Orion 28 ish) but on the Motorway it wasnt as much as you would think, (Fiesta 48ish, Orion 43ish if memory serves me well).

    This was probably due to the low gearing of the Fiesta 24ish? per 1000rpm (it wouldnt pull much more) against the orions 28?, So a Diesel still made sense but really depended on your driving needs, The Orion was a much more comfortable car than the Fizzbomb but as I recall to have bought new the price’s were similar to each other except you got a small amount of luxury in the GL spec Orion against the almost poverty spec Fiesta. (though ours was the last of the run out mk2 model Festival edition, which had the XR2/Ghia type dash). However am sure that Ford Dealers had plentiful Orions awaiting a buyer, so plenty of discounts….whilst possibly they had to order in Diesel Fiesta’s with the “take it or leave it price” approach.

    Over the next 20 odd years and staying loyal to Diesel, with Fords (very economical), Peugeots, Citroens (little better than Petrol equivalent but quite reliable), and a few VWs and have never had an issue with the Engine faults, (although we had a Citroen ZX that had a habit of eating Glow Plugs but thats another story), whilst many Friends/people I have worked with have had major problems with Petrol cars Coil Packs, ECUs, various sensors and I still hear of Engines Expiring early in life.

    However I hate to bang on again about our Golf mk6 Stupid Motion but it really is a load of Horse Poo, granted the over long gearing is wasted in the Hilly North East but we still dont have the benefit of going down hill on the other side! 42ish in town and 48ish on Motorway’s and has been in and out of Dealers trying to put it right but it still runs like a bag of sh”te, Our 11 yr old mk4 is still running Gracefully which gets more mpg too and other than service items is still using all of its original components including its Exhaust.

    Manufacturers have for me reached a point (pre DPF) then gone backwards with so much to go wrong it makes little sense buying a Diesel unless you keep trading it in every three/four yrs, or as they say “if you cant beat your previous effort, then make it worse but proclaim it to be superior, then fix all the wrongs and so you can then hype up the Fixed version” Any bets the Mk7 Golf will be Vastly better than the old mk6….

    As for the old rule that Diesel is worth more than Petrol …OK this is just one Manufacturer but VW Dealers are full of 1.6TDi’s which are cheaper than the Petrol Equivalent and anything Bluemotion is almost unsalable.

  15. My personal oppinion is that diesel is good for tractors or vans, not for cars. I was always of the oppinion that diesels are not saving costs machines and finding silly cars like the XJ diesel (or big MB, BMW or audies) big exsecutive cars made for people that can afford to pay the petrol for that expensive cars, a nonsense for me.
    in my personal oppinion a diesel with auto gearbox maybe takes you from point a to b but is not driveing and enjoying your veichle.

  16. I think diesel autos do make sense. Manual gearboxes are great for cross-country work on A and B roads, but if your journey involves city driving at one or both ends of your commute to work, and with sufficient distance in between, then you will get the benefits both of better fuel efficiency from the diesel, and relief from constant gear changing and clutch balancing in dense urban traffic, where there is no pleasure in changing your own gears.

    Further, modern diesels with their torquey engines suit the character of automatic gearboxes very well.

    If I were an urban taxi driver, I don’t think I’d want any other combination than a diesel engine and an auto box.

  17. My experience is of a Fiat Croma 150 which perhaps combines the worst of Fiat and especially GM. Under warranty it required a new alternator and egr. Out of warranty all four springs have been replaced. At four years old another alternator and egr. My mileage is now only 7k per year so the particulate filter has been regenned twice. Basically a car that should be nicely run in and that has been meticulously serviced and should run another five years easily is in fact a pain in the butt and highlights the worst of car manufacturer’s cynical approach to reliability of components

  18. @Francisbrett – In your humble opinion is there any vehiclefrom any manufacturer thats safe to buy! So far youve trashed Transit Vans, Merc Vans, any sort of Diesel car and now the Ford Ecoboost, an engine thats only been on sale since April!

  19. …..I would like to add that I (personally) prefer driving a powerful Diesel engined car over a similarly powerful petrol engined car now – once you get used to the torque, petrol feels a bit gutless, and I don’t like driving a car on the red-line all the time to get the performance……incidentally, how come BMW offer Diesel cars that now often out-perform their petrol counterparts……..

  20. @18 most cars are shit,some i tolerate,its my job motor vehicle engineer,so you get that way,whether the ecoboost has been on sale since april matters not,it is already on patch2 update.

  21. I use a highish mileage Pug 406 hdi estate for carting my gear about It replaced a 405 on which the driveshaft went. It plays the part of work van very well, and doubles up splendidly as a
    family motor on weekends. If I could find a petrol equivalent that gives me the combination of torque and mpg I might consider it, but at this time I will be sticking to pug diesels.

  22. Ooh! this also let me back in as Gaz rather than thegravestoneman, I don’t think I will ever understand the machinations of this site.

  23. @19, Simon Hodgetts,

    BMW diesels outperform their petrol equivalents becase they are not actually equivalent. Much like those of many of their competitors.

    Diesels are almost always turbocharged, twin turboed, and now with the diesel M5, triple turboed.

    Nothing wrong with that of course, turbocharging a diesel makes a lot of sense.

  24. I will only talk about my S-Types experience, and it is 2002 V6 manual Sport VS 2007 V6 twin turbo DIESEL auto XS. The old girl returns 28.8mpg the newer 36.7, not a great difference, and these poor results(esp. diesel) are due to very short journeys day in day out. That’s what the trip computers say, the A settings were from day one, I use B every time I fill up. However, the diesel graced me with high 40’s mpg on the “maiden” voyage from Stratford to Glasgow, something the petrol is unable to achieve, I got 32mpg last summer, going to France to see my mum. I don’t know if an auto V6 petrol would give me such good returns, and vice versa, would a manual diesel give me more mpg, I think that the auto goes down a ratio too often, but then again, some momentum(RPM) has to be maintained to keep going due to the inherent turbo charged engines nature. I find the diesel less sure footed, quite nose heavy, but then again, the petrol had new dampers fitted before I bought it, the power and torque delivery of the diesel is fairly brutal, short lived (1500-4400 rpm vs 1500-6750 in the petrol!!) hence I prefer the petrol built up. Then again, manual VS auto I have more fun in the old girl than the new one. It’s my first diesel in 21 years, there isn’t much difference inside when noise is concerned, I couldn’t say the same on my new Corsa viva in 1991(that’s Nova for Continental Europe) although the 1L was very rough on these cars. My job will change soon, the diesel might come more popular as I will have 40 miles a day commute, in the meantime, if you don’t pile up miles, petrol is best, no need to take the car on M’way for no reason but clean the pdf, as it has restricted the performance, I have to do this every other week, rendering the mpg advantage to nil, add up 5-8p more per litre and paying at least £1000 more than the V6petrol equivalent, diesel doesn’t make sense financially unless you’re a rep doing m’way miles at your company’s expense… Lesson learnt, but the 2007 version has a much nicer a*se than the 2002!

  25. My Berlingo 1.6 HDi outperforms my wife’s 1.6 petrol in performance and economy, even having done twice the mileage.

    I could never run the petrol for business, I’d be potless 2 weeks into the month. I get variable mpg from the HDi, but I can safely say that an average of 50 mpg, even in town driving, is achieved fairly consistently. As for performance, I agree with a comment above about a petrol equivalent being gutless, as I can oevrtake fairly comfortably from 40 mph in 5th gear in the van, impossible in the car.

    The fuel price is an issue, fair enough, and I do know someone who told me he gets 19 mpg from his SAAB diesel. In saying that, most people seem compelled to wring the nuts off their diesel cars so those sort of figures are no surprise. If you treat them right & service them on the intervals then you will get what you want from them.

  26. @24 Chris Baglin

    “…with the diesel M5…”

    Please tell me they haven’t made a diesel M5. Please…

    Is nothing sacred?

    edit: just Googled it and yep, it’s a reality. I don’t care how much torque it has (and it certainly has a lot), a diesel M5 is just wrong on every level.

  27. if it sells, bmw won’t have any shame, watch out for a RR diesel. Next will be Bugatti Diesel, or will they do Bentley this “courtesy” first? Nothing’s sacred Steve.

  28. One thing to note is that this is UK specific. In Europe you will see a bigger advantage in cost as diesle is cheaper. Maintenance on a Diesel is generally more expensive though.

  29. @27, Steve Bailey,

    I think a diesel M5 Tourer would probably make an excellent Police traffic car- with the weight of equipment the torque will be very useful, plus better economy when cruising, it will probably be faster in ‘real world’ driving than the petrol M5.

    Hope Jaguar can up the ante…

  30. Ford TDCIs: great when they work but eye wateringly expensive when the injectors go, which is a shame.

  31. It’s the future maintenance cost of the turboed small eco engines tht Which should look at next. Thses are never going to last the course.

  32. my classic sd1 v8 makes sense now glad i kept it, dirt cheap parts always reliable!! my old 300 tdi disco is a bit slow on take off but is pretty economical and torquey!! what more could i want? best of both worlds…

  33. I’ve just checked the calander to check the year. Typical Which?, “discovering something the world already knows. All modern engines have lots of hidden nasties. for me, unless it is a city car I’d always buy a diesel -so much nicer to drive. It’s not just about economy anyway.

    I’ve driven turbo diesels for 20 years now and am always amazed how gutless the equivalent petrol is. now petrols have gone smaller with turbos etc, what’s the difference to a turbo diesel? Perhaps the knockers should get one of those cars that say they’re poweeed by fairy dust!

  34. I once had a ZX diesel that used the old XUD engine.
    Reliable, economical, simple (no injectors), ran on biodiesel. Only problem was being non-turbo it was slowwwww.
    It ate glow plugs for a couple of years, until the last mechanic explained that the mechanic previously had neglected to replace the 4th “hidden” plug.

    Also had a ZX estate TurboD XUD for a while. Didn’t own it long enough to get a good sense of reliability, but it had 180k on and drove well enough.

    My last car was a 406 HDi and I wasn’t impressed to be honest. Seemed to only get 40mpg and ate a MAF and exhaust flexi (which required a new cat) probably because the mounts were knackered too.

    Current car is an Accord coupe a 2.0i vtec with an autobox. Very thirsty (25mpg) but very reliable (no £300+ jobs every few months).
    I’ve been put off by modern diesels, the peugeot and Honda forums have a lot of horror stories with DMFs etc., so my next banger might drink from the green pump again.

  35. Never owned a diesel yet so can’t really comment either way. However my brother owns a Jag XF TD which seems good.

    The new Ford Ecoboost 1 litre sounds good on paper with its high power output, but not sure I would trust it for the long term. My preferred choice would be the 1.6 Ecoboost (150ps version)

  36. I’ve heard the XUD was ahead of the game in the 1980s, & certainly up to giving 20+ years of service with the right amount of TLC.

  37. Never liked ’em probably never will’ I bought a 2007 Golf GT Sport diesel. It was noisy, peaky in its power delivery and i won’t have it that any diesel doesn’t smell, they do! Swapped back to a petrol for my current – a 2009 Lancer GS4 saloon and probably won’t change back, indeed the salesman openly said the Lancer diesel with the 140ps VW TDI PD was a ”plastic” engine that caused no end of faults in the Grandis and the Lancer’s which was losing them customers. I believe in Europe the Lancer’s now use Mitsy’s own diesels. I recently tried a 1.0 Ecoboost Focus. New Focus is absolutely nothing to shout about; nasty interior, awful ”sporty” ride, and ugly styling, but the biggest let down was the rave about 1.0 engine. I dread to think what these are going to be like after a few years. For me this new wave of 3 cylinder engines is just all wrong in anything but city cars and superminis. In a Grand C-Max it must just be embarassing.

  38. A chap I know has a new Jaguar XF-R. 5.3 litre V8 Supercharged, 503bhp. It will do 30mpg on a run, but will demolish 50-70 in 1.9 seconds.

    It sounds incredible and, as the owner says himself, it’s worth every penny of a litre of unleaded, and at £65k, why should I worry about MPG?

  39. Ive often said that manufacturers (and the international standards people) need to consider the whole carbon foot print, not just the first 15 minutes of emiissions the car produces when its turned on. electrical appliances the same. they should be made to be durable and reliable first and foremost. then the emmissions should be reasonable, and not compromise reliability. what we are seeing today, is that emmisions are the primary concern, at the great expense of durability and reliability to the point that cars are becoming more disosable too early in their life, hence their overallcarbon foot print, is much worse than they ever were. alex

  40. A friends just out of warrant BMW X5 diesel (owned from new, fully serviced, low mileage) developed a faulty diesel injector (common apparentl) after all the diagnostic and repair work was completed it came to about £1000. Tyres and MOT also due so all in all, almost £2000 to keep the almost as new ludicrously expensive car on the road. Madness!

  41. My old 1.8 Fiesta non-turbo disel (MK3) on the other hand ran and ran, didn;t have a turbo but also no lag, went like a train and did 55mpg whatever I did. Same goes for the old Prima Diesels in the ARG cars. Why did diesels have to all come with Turbo’s and tuned to be sporty, there was nothing wrong with diesels of old and to say they were noisy is forgetting that modern rules now make diesels noisier than their forebearers… Ok, the sound-proofing has come on leaps and bounds but still…

  42. @45 seven stages of fuel injection have made diesels quieter,especially pilot injection.As for the 1.8 d fiesta, it was fine in that car but torpid in an escort,i had a creg MK2 fiesta van with the 1.6D and it was fine>

  43. Ive been diesel since 1990..
    Two Montego’s (450k in one)
    Three Pugs. The Pugs all reaching the 400k mark.
    The best being a 406 1,9td.
    Now on a 406 hdi which is just ok but suffering at 310k with too many electronics tbh.
    The best to actually drive was a 405 1.9 run out model TD.Cumfy and an excellent chassis. A real pocket rocket.
    Its woth looking before you buy at the cost of MAFS and solid flywheel clutch conversions to save the dreaded DMF probs. (and of course a sympathetic mechanic!)


  44. Glad I sold my Touran TDi at 87,000 miles. Great car, but was just starting to get expensive. With a low-tech car I’m happy getting it fixed at a back street workshop where I know the staff and I don’t feel ripped off. ith a modern, high-tech diesel it feels necessary to go to a main dealer or an independent specialist, who will charge more. The petrol TSi models (and the Ford Ecoboost) will, I fear, also be expensive to fix and have expensive, high-tech things to go wrong.

  45. This article is basically twaddle. Like Auto Express, Which? are desperate for a catchy headline. And like Crimewatch on telly, they love to scare people. Diesel cheaper then petrol? No headline, no scare factor. Petrol cheaper than diesel? Shock horror!!!
    Over the last 21 years, I have done approx’ 168,000 miles in petrol cars, and 170,000 in diesels. My repair costs have been £1850 for petrol engines (chiefly an Astra that threw a rod at 106k), and £285 for diesel engines. Factor in a £3000 saving in fuel, lower insurance and depreciation (all cars bought secondhand), and lower tyre and exhaust costs, and diesel is a winner all round. Plus, they’re quieter on the motorway, and nicer to drive, unless you like the sound of valve bounce. I can’t imagine me buying another petrol engine. BTW tyre wear: my R8 216 got through 175/65×14’s in 10,000 miles; my 218SLDT kept 175/70×14’s going for 20,000, even though it had power steering, which the petrol car didn’t.

  46. Somebody mentioned swaping a DMF for a normal flywheel. Not always possible im afraid. A work mates T5 VW van clutch went, his friendly tame mechanic tried to swap for a solid flywheel, can’t be done:(
    10 to 15 years ago I would agree with most diesel lovers, now I would only buy new and get rid after say 3 years. I would never buy a modern diesel with high miles. I certainly would never ever buy one of the Ford TDCI Badged cars. I have a friend who had a new Mondeo dissaster! My very good friend in the trade advises don’t touch any of them!

  47. “I once had a ZX diesel that used the old XUD engine.
    Reliable, economical, simple (no injectors)”

    It won’t have got anywhere with no injectors. 😉

  48. You have always needed to be a high mileage driver for them to make economic sense. Even so now I’m a low mileage driver I like going six weeks between refuels and I prefer the way they drive.
    I’ve been driving diesels since 1985 and as far as reliability is concerned:
    Escort 1.6 – one frozen fuel filter, two batteries (needed a lot of churning), one injector overhaul in 130,000 miles
    Mercedes 190D and 190D 2.5 – no problems 50,000 miles
    Montego 2.0DSL and 2.0D Taxi spec – no problems 260,000 miles
    Rover 620LD – blocked fuel filter 120,000 miles
    MG ZT – just had a mass air flow meter, 98,000 miles and 8 years

  49. @52 i cant swap my oscillating DMF on my GT TDI golf either,a new one from VW tps £200 and £150 for cluttch and concentric slave,i will do it myself so not too bad. The old mondeo >06 TDCI are bad engines (injector/pump wear)the DV16 2.0l D are not bad really.

  50. I was seriously thinking of buying a second hand merc e320 cdi but having read the horror stories of the c220 and e220 cdi injector failures delphi admit there are faults.the problems are when diesel engines try to perform like petrol cars and wont last. i am now buying a e 320 petrol. 5p a litre cheaper, £2500 cheaper to buy and i do 9000 miles a year and it is only a few miles per gallon dearer to run, insurance the same but tax is a little more expensive, the petrol is more reliable and it is quieter and is cheaper to service and no headaches over rediculus bills!!!!!!

  51. Before I bought my Diesel MG ZT new I calculated I would need to keep the car for 3 years before I recovered the extra purchase cost. 85000 miles later I’m now reaping the benefits. As far as running costs go I have had to replace tyres, change the oil and filters, replace 2 cracked suspension springs and have the under bonnet Bosch fuel pump repaired after it began weeping. Can running a big 135bhp new car get any cheaper than that?

    The car has never broken down or failed to start and I get over 600 miles between fill ups. I am a very satisfied MGR customer.

  52. i think fords new 1,000cc engine will prove to small in a focus size car long term , if you look at fiats 1300cc diesel ,a good powerfull unit that is also put into large cars/vans , they have now made a chage to 1600cc , i think ford will have to up there engine toat least 1200cc , for long turm reliabilaty,,,

  53. The Which report is very unfair. I own an 07 Audi A4 S Line Avant with the VW TDI 140 bhp engine. It covers 300 miles a week commuting with costs of £40 – £45.I Petrol costs would be double that!

    Why would a diesel engine without DPF not outlast a petrol either as it does not rev as highly as petrol?

    I did my homework before buying the Audi and discovered that the TDI BRE engine does not have DPF and does not suffer from the turbo & injector woes of the TDI 170. Also the earlier BLB Engines suffered from broken/noisy oil pump drive chains whereas BRE have gear driven oil pumps. TDI 170 engines are 10 mpg worse than the TDI 140 and have more peaky power delivery rather than the lower end grunt of the 140.
    I have covered about 35K in two years of ownership and have had no major engine or ancillary faults. The car is serviced by myself and a technician friend regularly, particularly oil and filters.
    Simple summary do you homework, don`t steam in and buy a car without thorougly researching first.
    Which? Get a life and stop scaring people into buying reports! We life in the 21st Century now with the internet and owners’ forums! Pick your way through them ignoring the subjective stuff and you will find the truth!

  54. @59 my current everyday user is a BKD engined GT TDI golf 140 with a torque box (170 BHP)135k and rising is sweet as a nut apart from needing a flywheel soon as there is over correction on the rough running cycle on the injectors,i am easily getting 45-50 mpg throughout the range,but my Volvo S60 D5 is peerless-65 MPG,180 BHP manual and has covered in excess of 230k miles.Nothing but nothing can touch this in the real world,As for DPF’s they are not as understood as perhaps they should be,critical is the oil-low ash as specified,im no fan of these things at all but they do what they say on the tin,short city driving cycles without a periodic passive regen will soon cause trouble…….incidently there is a recall campaign by VAG for replacement injectors depending on vin sequence/siemens injectors.Owners should contact thier local dealer for advice.

  55. I do 30,000 miles a year in my 75 CDTi (and previously a 75 CDT).

    Ove the last 12000 miles between the two of them my extraordinary costs over and above servicing have a been 1 clutch and master cylinder, a starter solenoid and some work on the front suspension, all on the CDT. The CDTi has not missed a beat so far. Both averaged 40-48 mpg. Both have towed a 1300kg caravan frequently.

    However I do dread the ownership costs of a truly modern car, petrol or deisel when they get much older than 6 or 7 years

  56. My 2008 Audi avant S line has the BRE engine, same as Tony above but it has a DPF so not all BRE engines are the same. Mine is an Audi A4 S Line TDV, Audi for particulate filter.

  57. It is very true that you can save money on lower fuel consumption with a modern diesel then lose all of it in one bill for a DPF or set of injectors!!

  58. old dieselall the way pug XUD weve 3cars with it in cant fault the 95 pug has no blower and sits at 267000 miles starts first poke smoke emisions 0.32 maintained by thebook may do decoke nex year

1 Trackback / Pingback

  1. Xj40 Running Gear | Wearable Tech Store

Leave a Reply

Your email address will not be published.


This site uses Akismet to reduce spam. Learn how your comment data is processed.