The point being made is that when a fault occurs, the newer common rail diesels can easily cost upwards of £1000 - partly because of component complexity [eg. dual mass flywheels], partly because there aren't yet the people to properly diagnose/repair.
I'm just starting on my third common rail diesel, and I did think twice before buying it.
My previous two (a BMW 330d and a Mondeo 130 TDCi) did good service but did hit engine reliability issues - the BMW was an EGR valve and an injector, the Mondeo an injector and the turbo. Prior to these I had petrol cars with no problems at all.
My overall feelings are that diesels are still reliable, but if/when a breakdown occurs you can be talking serious money. in some cases enough to scrap a 6-8 year old car!
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I do acknowledge the cost of repair argument but what I would like to know is what is the relative risk. Are we talking about 50% of diesels failing or 5% or 1% or what? And how does this compare with the equivalent petrol models?
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The amount of common rail and particulate filter problems /expense posted on here were certainly enough to put me off buying a CR,much as I would have liked one.It would be interesting to see the statistics though.
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Saving £5-£10 / week burning diesel appeals - however if there is a bill of £1000+ for injectors, turbos and DMF then I think a economical petrol has merits.
I have a diesel and get about 40mpg on a decent run, my DiL has a new Honda Civic - average over 40 and can get 45-47 on a long run - it is 2 years old and has been consistent in the mpg..
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There is no commercial gain in releasing car reliability stats, least of all from car makers. Extended warranty companies only seem to give relative repair costs on older vehicles. We will never see accurate breakdown figure from the recovery people either, they have too much to lose with their commercial links to car manufacturers.
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. Extended warranty companies only seem to give relative repair costs on older vehicles. Wewill never see accurate breakdown figure from the recovery people either.
I had a friend with a Mondeo - a few months out of warranty buty with a extended warranty through insurance - they did not cover injectors - BIG DOSE of REDEX put the lights out and he traded it in!
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Yes, and the stats can't take account of how a car is driven: even a full service hostory only tells half the tale. Look at the current Volvo S60 thread, where DP's has clearly been looked after by its previous owner, and PE's hasn't.
The only constant is the one mentioned by Marlot - when a diesel does go wrong it'll probably be more expensive to repair. It also seems that modern diesels are more complex than older ones: the ancient Perkins Prima would rattle on for years and take all manner of abuse, while the Maestro or Montego crumbled visibly around it.
I don't hang about, but try to drive with reasonable 'car sympathy' and (touching wood) I've had 40 years of reliable cars, including seven Renaults in a row. OK, I've been lucky, and there are plenty of good drivers who have been less fortunate, but I think it makes a difference.
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I've driven probably 250,000 miles in various diesels, the vast majority of which being the older non common rail type, and never had an engine related problem with any of them, if you exclude failed glow plugs. The cars include a VW Golf mk2 1.6D, Peugeot 306 D-Turbo (XUD), a Polo 1.9D CL, two Focus TDDi's, a Megane 1.5 dCi 106, a mk2 Mondeo 1.8TD and our current family chariot, a 2004 Grand Scenic 1.9dCi, currently on 52k and still punchy, smooth and with near zero oil consumption.
Admittedly, the mileage on the common rails has only been about 30k of the total covered, but the only trouble has been glowplug failures. The Fords stand out as being the most impressive having literally been completely troublefree in the engine department in over 150,000 miles covered between them.
I agree with Avant, a lot hinges on maintenance and driving style. I've always made a point on the turbo engines of driving sympathetically until warmed up, and allowing a minute or two of gentle running or idling before switching off, for example. Regular level checks, servicing religiously to schedule (or sooner), and with particular attention to fuel system maintenance such as frequent filter draining and replacement.
That said, I am aware that one fault on the Scenic could cost more than the maintenance bills on the rest put together, but I'm a natural optimist ;-)
Cheers
DP
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it would seem to me that cars in the past 10 years have become considerably more reliable than they were of old (petrol and diesel)...and...for daily running costs reasons many people have swapped from petrol to diesel more recently
however, you can't really equate the reliability of diesels versus your past petrol car reliability, if my above assertion is correct....because they've all become more reliable, so if you'd stayed with petrol they'd have been more reliable as well
I can't answer the poster, but a good friend has just had an £800 diesel fuel pump bill on his 5 yr old Transit which was an eye waterer...and makes me think a bit with our long distance car being a 2.0 turbo diesel that is just out of warranty
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Three words spring to mind, party, warranty and third.
Edited by Pugugly on 26/04/2008 at 23:07
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Been running a Skoda Fabia VRS for three years and that has been very reliable. The umoe Duse engine is still available in VAG cars and although a noisy engine is reliable from what I have heard except for DPFs on the top 170 BHP cars. It is the complexity of high pressure injection systems, sophisticalted variable vane turbos, dual mass flywheels and exhaust gas recirculation that means costs can be prohibiive when htings go belly up. I am afraid the old "there's less to go wrong dos not stand up any more".
You still ave oney on Diesels everyday though becasue the price differential is only between 95 Ron and Derv. Most modern petrols run much better on 97 Super Octane and so you are paying the same anyway. Go for a japanese or German Diesel and you should be o.k. My brother in Law works for a Ford dealer. I was going to consider an Focus 2.0 TDCI. A great car but he stated that the engines are prone to problems and cost the earth to fix! Alternatvely if you are not in a hurry seek out a late 80's Mercedes 300D. Indirect Inline injection pump, simple ohc design and beautifully smooth. That at and the 190D 2.5 put and modern Diesel to shame for refinement. Oh I know a bloke who has one wih over 500,000 miles on the clock! (190D 2.5)
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Go for a Japanese or German diesel and you should be O.K.
What; like a Mazda 6 - or a Merc CDi - or a VAG V6 TDi - or a BMW?
You nailed it in the first paragraph; diesels can be [and were] simple and reliable - they just can't be clean too.
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Absolutely right although mazda normally get things pretty much bang on with reliabiliy so I am surpirised if their Diesel is dodgy. After all they made the Rotary reliable! I know a guy who has an A4 2.5 TDI which ran fine until the dealer overtightened the cambelt tensioner at a service and wrecked the engine when the belt snapped! Luckily they forked out. Woudn't touch a Merc CDI as it costs about £600 to change the glowplugs!
P.S sorry for earlier typos I meant of course PUMP DUSE. Must learn to type!
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The Mazda 6 diesel does have just a few niggles..... Prepare to be surprised....
Volume 1
www.honestjohn.co.uk/forum/post/index.htm?t=57098&...3
Volume 2
www.honestjohn.co.uk/forum/post/index.htm?f=4&t=62...7
don#t know what happened there, Screwlose, but I've fixed it
Edited by Pugugly on 26/04/2008 at 23:50
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Thanks for all the replies so far. As usual there are some very interesting personal views being expressed but also as usual, with all due respect, no hard facts have been presented which quantify this assertion that modern diesels are inherently unreliable. In the current absence of any numbers to analyse, here are some trivial ones to be going on with.
As I previously stated further back up the thread. I guesstimate that the effect on my fuel costs over my past 12 years of dieselism is a gain of £20k. Apart from the accursed Renault all my cars have been ultra reliable. As it happens the Espace was leased and therefore under warranty so it didn't cost me anything but my patience.
Leaving my gallic encounter one one side, just suppose for a moment we look at a scenario where over a similar 12 year / 500k miles period that I have 6 more diesel cars. Let's imagine that every other one suffers a catastrophic DMF failure or some such. Let's allow, say, £2000 of extraordinary cost in each instance. Even if fuel were to remain at today's bargain prices I would still be something like £14k in pocket at the end of the 12 years by sticking with diesel and assuming no problems at all with the petrol alternatives. So in other words even if 50% of diesel engined cars suffer a failure of this magnitude during their "lifetime", for a high mileage driver it is still measurably and appreciably cheaper to run a diesel with or without a warranty.
OK so I'm posting drivel to make a point. I don't believe for one moment that the chances of major failure are anything like 50%. Based on my own experience they are in fact, minimal. I accept the fact that it may happen one day but I might also have a substantial win on the lottery. Not for one moment do I deny that some cars have had problems and when they do they are expensive to fix but at the risk of being repetitive, let's see the numbers please.
Without the evidence to the contrary you could be drawn to the conclusion that this is yet another example of the British propensity to love wallowing in and spreading bad news when in fact the reality is something quite different.
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shoespy
As already said; nobody's going to reveal the true facts. [Look at the Mazda and Ford dealers' attitudes of blank denial.]
My own guess is, over a 3 yr period, that 5-10% of CR diesels will suffer a serious fault [over £1000] and far less than 1% of petrols.
However; given the appalling consumption figures of the latest diesels and the cost of maintaining their power-sapping emissions gear; the price differential of the fuel; the extra capital cost and the increased maintenance costs - petrol is now cheaper overall.
I'll stick with my [old-tech] diesels though - I just like 'em.
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Think the general consensus here is that you should be o.k but there is awful lot MORE to go wrong and it is a lot more sophisticated stuff and hence costly should you be unlucky If you are lucky fine and touch wood I, like you have been but Screwloose above makes a valid point. If you want statistics write to the AA or RAC if you are a member or, best of all when you take your car in and if your mechanics have brain, ask their advice.
You pay your money and you take choice.
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Speaking personally, and i've run diesels since about '83 or so, can't exactly remember.
I never had a problem with diesels i've bought, including the couple i've bought with engine problems cheaply which were simplish to repair/overhaul, but as already said these were very old school diesels and as such were built for reliability and fuel consumption not performance. (Granada 2.5 peugeot lump completely worn out at 80k through non servicing, mk1 golf holed piston, both easy repairs and years of service after)
Couple of observations though.
The best diesels i've owned have all been well serviced throughout their lives, none of this 20 thou miles rubbish.
Whilst in my care the cars have been driven hard, only way to make the old type go, but always allowed to warm up before thrashing and allowed to cool if turbo'd.
Whether my own experience is common i know not.
The stories we hear of failures with the common rail motors has put me off buying used cr diesels as i don't want someone else's neglected or misfuelled or generally abused rubbish.
In fact almost every engine failure i've known about has been with owners i know do not service their vehicles adequately or treat them with care, someone in my own family bless em comes under this banner and always has fuel system problems on their diesels, and can't see the connection.
I'm not terribly convinced by all this hype about how fantastic modern oils are compared to twenty years ago, similar to hearing a politician speak, the makers tend to tell you what you want to hear. I wonder for example if there's any relation to the apparent short life of x trail turbo's and some starship mileage oil change intervals.
I've always been under the impression that oil has to work very hard in a diesel.
All my own observations, and i wonder if someone who looks after their vehicles would be able to run supposedly troublesome cars for years with no probs whatsoever.
You seem to have had good fortune with your diesels Shoespy, i'd hazard a guess you have treated those vehicles well though.
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You may be right GB. I do try to drive with an amount of mechanical empathy without sparing the horses. Like you I don't ask too much of the engine until it is up to temperature. Personal rule is no more than 3000 rpm until up to temp, and I always allow it a minute or so to "warm down" before switching off. My cars also always get serviced on time as per manufacturers schedule albeit by a local garage. I am also careful never to dump or slip the clutch and use first only to get the wheels turning and save the harder acceleration for second upwards. Maybe it helps.
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Agree with everything in your above post GB
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Interestingly enough petrols are starting to get more complacted as well - probably the most complicated engine on the market at the moment is not a diesel, but a petrol - the VW 1.4 TSi with turbo and supercharger....
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>Look at the Mazda and Ford dealers' attitudes of blank denial>
Is it any wonder considering the lucrative warranty work they can coin in to make up for the narrow margins on new car sales?
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We have had this debate before.
It's all about Delphi systems which are marginal.
Guess who uses Delphi?
Ford.
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>>the lucrative warranty work they can coin in
Not really.
Warranty work is not lucrative for dealers. First, the hourly rate that the manufacturer pays the dealer for warranty work is nowhere near the hourly rate paid by customers. Second, each warranty job is followed up by a more torough evaluation and coding work by the dealer to enable them to make the claim - this can take some time to find and enter the correct codes. Third, there's a reasonable risk that the warranty work will be rejected, either the whole job, or a proportion of it during a warranty audit, which manufacturers like to spring onto dealers.
In short, dealers are much happier doing servicing work for cash paying customers.
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>>none of this 20 thou miles rubbish
If this really were true, then engines would be failing with great regularity. The technical side of this forum would be full of people asking about re-bores, crank grinds and new pistons. This isn't the case, therefore, the 20,000 mile oil changes are appropriate for most vehicles where this is specified.
I would not be surprised to find that most cars reach the scrapyard without their engines having ever been opened up for anything other than routine servicing.
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I would not be surprised to find that most cars reach the scrapyard without their engines having ever been opened up for anything other than routine servicing.
Nail squarely on the head of my point NC.
Maybe the statistics I am asking for are not yet in the public domain but if this is the case, I call upon anyone who knows how to ferret them out to please do so.
So far, all we hear is the automotive equivalent of " I, and someone I once heard of, bought a bad apple from that supermarket."............ "Therefore, if you buy apples from them, they are more than likely to be bad." Sounds like a bit of an over reaction when you put it like that doesn't it?
Perhaps I should ask the Mods to change the thread title to " Diesel reliability - the facts" if it's not too late?
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I honestly think the only way this will be settled is if there's a website dedicating to taking records of problems people have had with their cars, and have some simple way to verify the matter. Get other car forums to make the site a sticky and encourage those who are involved to fill in a quick 5 minute form on the matter.
Whilst there are people in the industry who clearly have solid experience in the industry, a bigger sample would really help show who's particularly weak and who's particularly reliable, and may even encourage manufacturers to somehow improve on these matters?
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To be fair to the manufacturers they have improved reliabilty beyond all recognition, as anyone who has owned/driven a 60s or 70s car will tell you... even more impressive as cars have got so much more complcated than they were with all the add-ons such as ABS, airbags, engine management, etc, not to mention all the "luxury" electrical items.
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I think that although there are many factors which skew the type of people who will post on a site like this, the posts in technical do give us a snapshot of what sorts of faults are prevalent - in other words, this site itself is a potential source of the data you seek.
In a purely unscientific way, the feeling I get, based upon the numbers of posts in technical is that CR diesel failure are about as common as catastrophic engine failure itself, but, dual mass flywheel failure in particular is becoming rather more common.
Engine failures are so rare these days. In the late eighties, i the Vauxhall garage where I worked, top end overhauls, valve stem seals, camshafts, fitting GMX engines were all reasonably common tasks. Now, according to my ex-colleague who works there still, these jobs are rare and unusual, and so take much longer to do, because even the dealership mechanics do not have the level of familiarity required to turn the jobs round quickly.
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I wonder if HJ has any record of the fuels used by the "problem" diesels he reports? Or thoughts about the reliability implications of veggie diesel in CR engines?
(I now run my MINI D exclusively on BP Ultimate because it is quieter and more responsive that way, and the few pence more per litre doesn't bother me when I never get LESS than 50 mpg.)
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It seems to me that the `best indicators` are going to be provided by independent Mechanics/Techs such as Screwloose, who have an overarching overview and yet no main dealer/Manufacturer agenda that could impede honesty.
Regards
Edited by oilrag on 27/04/2008 at 12:12
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I know that in the Motoring Which yearly report, when they used to use the 'star rating' for 'faults', 'niggles', 'breakdowns' the diesel versions of popular cars nearly always scored less well than the petrol versions.
I have never seen any hard statistics, but then I supposed manufacturers prefer to keep ALL such data confidential!
I have only anecdotal information - I work with a number of people of commute in diesel cars and they nearly all seem to have had either fuel system or DMF-related problems. IIRC the only guy who hasn't drives a Passat, which seems to be a good one. I don't recall anyone talking about major problems with petrol engines. I think most small-time independents can fix a petrol problem easily and fairly cheaply, whereas with a diesel it seems that even small defects cost big money to fix and there is a dearth of repairers with the right kit and skill set.
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... in the Motoring Which yearly report when they used to use the 'star rating' for 'faults' 'niggles' 'breakdowns' the diesel versions of popular cars nearly always scored less well than the petrol versions. ...
Although that could have been - at least partly - because diesel drivers drive higher mileages, so more opportunity for things to go wrong.
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Point taken NC, but doesn't oil do other things other than protect bores from wear, especially diesels where the fuel itself is a fine lubricant for bores etc.
I'm thinking more of the extremely small bore oilways involved especially with turbo's, of which there are a number of regular failures reported, also hear periodically of timing chain guides and other such parts wearing out with catastrophic failures.
I'd be surprised if anyone making enquiries on our technical forum about overhauling their worn out engines would be leaving their oil changes to these astronomical mileages. I'd be more inclined to think that people who do the bare minimum to their vehicles come into to the use and dispose category, and i can't see them dismantling an engine and getting rebores etc if they can't be bothered to change the relatively cheap oil. They've probably disposed of the vehicle long before that, after the second or third turbo failure or the original cambelt snapping long before serious engine wear could result.
Vast majority of new vehicle private buyers are going to replace within 100k anyway, hence the often heard suggestion on this forum, its not worth looking after/rustproofing/servicing etc as i'm going to sell it soon anyway, i'm not criticising that viewpoint, but there are some of us that prefer to look after our things better than that.
By the way, you come from old haulage background, at work when i'm loading alongside several other transporters all at approx 800rpm with the pto's running, you wouldn't believe the stink of burning oil that some of these very modern trucks make, and i believe most of this premature wear is down to ridiculously high service intervals, not that it matters of course because most of them will be at the docks by 5 years old being exported to another thirld world country, damage already done.
Disposable world, not for me.
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I asked my brother in law about the ratio of cars that come into his garage with major engine problems and failure and he said that almost all of them, say 98% are Diesels. According to him the Petrols are far more reliable. I wanted a Focus 2.0 TDCI as previously mentioned,he said avoid like the plague. My sister traded up her mark1 Focus and tried a 1.6 TDCI and loved it but he partner refused to let her have the Diesel "I've got to work on the thing when it goes bang" so she got a 1.8 petrol: far simpler no turbo, no high pressure pump, no fuel rail.
No one can provide statistics that I am aware of but if you want the lowdown on engine reliability and comparisons talk to a technician. They are the best source of information. I bought my car with the TDI 130 Pump Duse engine in it and it has been fine. i bought that on he back of a recommedation from by brother in law who said the best Diesel Ford fitted was this motor in the Galaxy as i dn't want a people carrier bought the Skoda. Yes it's complicated as the injectors are run off individual plunge pumps for each cylinder and strain can high. You have to use a special oil but I know these engines can do mega miles if looked after. Another good source of advice as to modern Diesels is to go and have a word with the guys at your local TAXI RANK: they have seen it all.
Edited by Mattbod on 27/04/2008 at 14:14
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If things were as bad as you indicate, Matt, it would be all over the Press, as its isn't I'll take these rumours of mega problems with diesels for exactly what they are, rumours....
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I bet HJ wishes people would stop sending him e-mails of the rumoured problems they have with their diesels - especially as they are only rumours.
Also I wonder if the jazz would continually be the most reliable car in the UK if it had a diesel engine - just a thought !
Edited by Pendlebury on 27/04/2008 at 20:40
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I don't think anyone is denying the reality of there being issues. All I am trying to get at with this thread is to gain some understanding of the size of the problem.
I only stumbled upon this website about a year ago and if anyone had previously tried to convince me, for example, that Ford diesels had reliability issues I would frankly have laughed in their face. My views prior to reading some of the tales of woe on here were entirely subjective and based upon my own experience or that of people I happen to know. On that basis I was simply not aware of the existence of DMFs for example, never mind their vagaries. My experience, it would now seem, is one of astonishingly charmed luck if the collective view of some forum members is to be taken as fact.
I was simply wondering if anyone could quantify any of this. It would seem not, but thanks to all respondents anyway.
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"Another good source of advice as to modern Diesels is to go and have a word with the guys at your local TAXI RANK: they have seen it all. "
Exactly - so why are the vast majority (?) running diesels if they are so unreliable?
Where are all the questions on the Technical part of this site about "unreliable diesels"?
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