I am considering buying a modern diesel, particualrly either Toyota avensis, honda accord or Mazda6, and was wondering what the position was with these newer-style diesels when they start to get past their first flush of youth, and the mileage racks up, and they have to get through the emiisions test on the MOT.
My father used to have an old-style diesel (Citroen XM 2.5TD) and I always remember him getting rather twitchy near MOT time, putting in injector cleaner, and thrashing it down the bypass before the test to clean it up.
The older diesels used to be either worn/clogged injectors and/or diesel pump calibration that caused excess emssions/smoke, or possibly blocked filters.
This wasn't necessarily huge amounts of money to put right.........
With these newer diesels what can cause failure,and what is needed/cost to rectify - do the injectors clog as easily (Are they more expensive to replace ?) , and is the timing done by the injection system now ?
What else can be a problem ?
The toyota D4D engine seems to be particularly refined from what I hear (they are certainly quiet driving past) , does it have any quirks, and how to people rate its longevity and general perfromance/economy/reliability ?
Edited by Dynamic Dave on 23/10/2007 at 13:37
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As well as the injectors & emissions there are other worries
Dual mass flywheels and clutches have a habit of costing a lot £1200 is not unknown for the pair to be replaced - both are needed at the same time or rather should be done at the same time.
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Friend who works for Toyota currently has an 07 Lexus IS220 with the same D-4D engine as the Avensis, and has had problems with the injectors. According to him, diesels are low-priority for Toyota/Lexus because only Europe buys them, and the UK takes half of them, apparently.
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With these newer diesels what can cause failure and what is needed/cost to rectify - do the injectors clog as easily (Are they more expensive to replace ?) and is the timing done by the injection system now ?
Modern diesel fuel systems (excluding those on the VW group TDI units) now work on a similar principle to petrol fuel injection systems.
Fuel is pressurised by a pump and circulated through a fuel rail, to which the fuel injectors are attached. The injectors open and close independently of each other, and under full ECU control. Yes, these engines are like a petrol equivalent in that they are electronically controlled and that the DIY mechanic can now do virtually nothing with them when they go wrong.
The principle differences are the pressures involved which can exceed 20,000 psi on a modern system, and the fact that most diesels inject their fuel in several small pulses on each cycle to reduce combustion noise. On an engine spinning at 4500 RPM, this means each injector can open and close several times and deliver a precisely metered amount of fuel every 1/37th of a second. It doesn't take a mechanical genius to work out the level of precision engineering required to achieve this, or to achieve a fuel rail pressure of 20,000 psi in the first place. Fuelling is in fact so precise now, that each injector comes with a code describing its flow characteristics which is programmed into the ECU to tell it how long to hold the injector open to achieve the desired fuel quantity.
And that's the rub with common rail. Technology gets cheaper, but technology isn't the key to a reliable common rail fuel system - high quality, precision engineering is. And that cannot be achieved on the cheap. A couple of quid unit cost on a modern car is a very serious amount of money, and there will always be pressure to keep these costs to a bare minimum.
That said, and despite the well documented issues, I am still of the firm belief that the majority of common rail diesels rack up six figure mileages with no more cost or drama than a petrol equivalent. The thing is, when they do go, the bills are so astronomical that people shout very loudly. And understandably so.
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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"The toyota D4D engine seems to be particularly refined from what I hear (they are certainly quiet driving past) , does it have any quirks, and how to people rate its longevity and general perfromance/economy/reliability ? "
I have a Yaris diesel. No quirks good/good/good/no problems.
I looked at several with 40 to 125k miles before I bought to see how they aged. All had FSH and drove rather like a new one.. Lots for sale with over 100k - a good sign.
Easy to maintain: the handbook has a DIY section..powerful (after 1600rpm) , 57-60mpg and much quieter imo than a diesel Fiesta and smoother.
After an Audi TDI , much much more refined...
madf
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thanks for the info so far lads.
as the system is so precisely engineered, then presumably regular fuel-filter and oil changes must be crucial, and of course using decent fuel.
Does anyone know whatt he "signs" are or what to look for when viewing a secondhand car to ensure that you are not buying one someone is trying to offload as a big bill is looming ?
I have seen an 53 Avensis D4D T-spirit with 60,000 miles at my local peugout dealer. I asked why they had a toyota, the dealer said the woman had bought it for school run but found it too big and had P-ex it with them for a 207 as she wanted somethig smaller. It does havea "cargiant" sticker on the back, which made me suspicious, - was it bought from them, and subsequently they found there is actually something iffy about it and they have offloaded it by p-exing it ??
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First check the service history. Must be Toyota, right stamps, dates, mileages.
Look at engine. Any signs of shiny new bits? (If yes , suggests troubles in past).
Check coolant colour... should be red on Toyatos iirc. No sign of oil/sludge.
Check engine oil... up to mark, not sludged. Take off filler cap. Any white deposits? (condensation or coolant in oil?)
Signs of rusty water on engine/radiator?
Oil filter should have been changed so should be Toyota and not extrenally very very dirty. If it is may have not been changed.
Start engine from cold. Do all warniong lights come on when you switch on? And go off when engine starts. Check oil pressure light goes out immediately.
Any tapping sounds? Does turbo whine?
If you are not sure, get an AA.RAC inspection.
madf
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SS
You can't take the risk of buying a modern diesel second-hand unless you know it's history.
Tens of thousands are mis-fuelled every year - that's death to a common-rail, anything from £2500 upwards to fix and a prime cause of off-loading.
It's become the norm for diesel faults not to be fixed anymore. A high proportion of the cars that I diagnose are never fixed; the finance is just rolled over to the next one and the horrendously expensive fault becomes SEP.
Yes; 90+% of these cars grind up and down the roads all day with no problems; the percentage that are traded-in with latent problems is very, very, different.
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There's about 5 million common rail diesel engines on the UK roads, so if 100,000 of then are misfuelled each year then that's 2% of them, so if I buy one at three tears old then I've got a 94% chance of it not having been misfuelled. realistically the chances are better than that, if a misfuelling in the first couple of years has caused damage then it's already likely to have been repaired, so I'm left with a 2% chance of a very big bill. That's a risk I'm prepared to take for the benefit of not suffering the bulk of the depreciation and the benefits of a tdci engine for my 30k miles PA.
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I read often, only post occasionally
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Mountains out of molehills springs to mind........
I've run a 1.9TDi PD for the past 6 years, sailed through its MOT the past 3 years - 82K on the clock at the last one.
Any car can be unreliable and fail its MOT, diesel or petrol - just that some like to knock diesels and spreading rumours about "supposed" weaknesses is their latest wheeze. And any well maintained car will pass its MOT, whether its petrol or diesel, if you're buying used check its history.
Ask yourself, "if modern diesels' record was as bad as some make it out do you think that people would continue to buy them?"
Answer - No they wouldn't - but sales of diesels are increasing, new and used, so there's your answer.......
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>>horrendously expensive fault becomes SEP
I see we appear to share a taste in authors Screwloose.
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b308 - I think the VW PD engines seem to be more proven to be reliable - my Golf has 114K on the clock (04reg Golf 150), and doesn't seem to have any major problems.
I'm not saying that some aren't unreliable - just that there are a lot out there with mega miles on. I remember a Passat taxi, probably a Y/51 reg (this is about 4 years ago) with 300K on it...
Perhaps the OP might consider a VW PD engine, whether it be via VW, Skoda, Audi or Seat?
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Sorry, it just seemed like scaremongering to me! All can engines have faults, and modern ones will ineevitably cost a lot to repair, though they are much more reliable (remember being pleased if you got to 30k without the thing breaking down? Bring back the 60s cars!!) - though it'll be interesting how reliability fares with the increased use of turbos in small petrol engines!
(btw I was recently in Brighton and Bournemouth and it seems a large percentage of their taxis are diesel Octavias, with most on 300k+ I shouldn't wonder!)
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Yes, there are lots of Skoda Octavia TDIs but also round these parts there are a lot of Mondeo TDCi taxis. I was in an 04 plater a couple of weeks ago showing 210,000 miles on it but the driver was a miserable get and I didn't feel like asking him if it had any problems. Seemed to run alright, although he was in full on cabbie fuel save mode.
I regularly go to the Netherlands on business, and virtually every taxi out there is an E class Mercedes either in 270 CDi or 320 CDi guise. Most of these have 200,000-400,000 km on them and still drive beautifully. According to the drivers I've spoken to, they're reliable as clockwork.
The 320's go like stink as well. Proper, back in the seat grunt. Lovely!
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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My dad has run all his driving school cars to in excess of 100,000 miles which takes about 3 years - currently he's on his second Fiesta 1.4TDCi. To my knowledge he has never suffered an engine/CR system/injector etc problem. Years ago he used to have glow plugs replaced, but even that is now no longer required.
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Surrey_Scientist
I run an XM 2.5, and they are notoriously smoky, even with all the precautions!
Anything else must be an improvement!
r
r
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a very nice car. Wish I was brave enough to run one!
JH
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a very nice car. Wish I was brave enough to run one! JH
It's wonderful! And not as scary as some make out. Plus there is plenty of support on the 'net
I'm glad that I took the plunge three years ago!
Back on topic - common rail diesels and an old-style lump with a history of smoking are not comparable. Even my XM scrapes through the MOT at 2.85 - ish (Limit = 3.00).
The XM's predecessor,a Peugeot 405 1.9 estate, when to 251K, and the emissions seemed to improve every year!
r
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Dual Mass flywheels were mentionned by someone as sometimes needing repalcement and being expensive - I've not come across these.
What are they/how do they work, what goes wrong with them, and what are the symptoms of a problem ?
Is there a "test" or anything specific to look for when test-driving the car to determine possible future onset of problems with this component ??
As regards mis-fuelling I was told by someone that people often have the car drained down etc. and seems to run OK, but if petrol has got into the pump, as damage occurs to pump innards because of lack of lubrication from the petrol, bits of fine swarf break off the inside of hte pump and slowly lodge inside injectotrs
Result - car drives fine after draining down but after possibly quite along time the injectors slowly clog up, and the pump continues to chew itself to pieces chucking off bits of swarf.
So theres a huge bill possibly 1000s of miles after the misfuelling, giving time to p-ex it on ??
Is this correct ?
are these new CR diesel pumps engine driven lke the old diesels or electrically operated ? Or does it depend on the negine ?
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Here's a recent thread that discussed the problems that dual mass flywheels can cause, and some info about why they are fitted.
www.honestjohn.co.uk/forum/post/index.htm?t=56785&...f
First signs of failure can include starter motor failure - the metal shavings from the failing DMF jam up the mechanism, and rattling and squeaking noises as the engine shakes when you either start the engine or stop it.
Mis-fuelling can damage the high pressure diesel pumps, as can contamination. After the event, this can be very difficult to prove one way or the other.
I think it's fair advice to suggest to any Ford owner that they take a sample of fuel and have it independantly analysed when trying to obtain warranty work on Ford TDCI engines.
I would have no hesitation in running an older diesel (in fact, I do!), and I would happily run a VAG group PD engine if I was sure it had used the correct oil, but, I would not buy a common rail diesel - I prefer to sleep at night rather than worry!. I'm sure that in a few year's time, these problems will have been ironed out, but, the purchase of a new common rail fuel system is not a fun way to spend money IMO.
Number_Cruncher
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I currently own a 2006 Mondeo diesel which has only covered 20000 miles. The car has not really run properly since about 5000 miles. Its been poor at starting and suffered intermittent misfires and flat spots, in some instances putting me at danger from other road users.
My Ford dealer (from whom I purchased the car brand new) seems to be totally confounded by the technology of the car and has now resorted to the position that I am responsible for the car's problems because I have used bad diesel. They are not suggesting that the fuel currently in the tank is bad, but that it has had bad fuel through it in the past. It is impossible for me to prove that this is not the case. The dealer is refusing repair under warranty and my only option is to go to court and involve expert witnesses and so forth. As a person with little mechanical knowledge I feel that I would be at a disadvantage (presumably Ford would be able to marshall a small army of experts to back their position).
The irony of my position is that I bought a brand new car to get the security of a full three-year warranty! I would not recommend purchase of a modern diesel until the technological shortcomings have been ironed out.
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I feel for you and for the position that you find yourself in. However, it would be unreasonable to condem every other diesel on the basis of the one you have unfortunately been landed with.
Much has been said about the Ford (Delphi) diesel problems. (Delphi are the Ford subsidiary which supplies the fuel system). Similiarly lengthy comment has been made about Ford's all too common "get out" of faulty fuel and it has been observed of course, that everyone else's diesel engines seem generally to manage perfectly well on high street fuel.
It should be pointed out to Ford - and this might form a part of your "defence", that diesel fuel systems fitted to engines have to be provided with an efficient filtration and water separation system in order that they may function in the real world. Your Delphi equipped vehicle has such eqipment fitted to it, made by Delphi.
We are in the UK with a highly developed and, in my view an excellent - in terms of quality and cleanliness - fuel distribution system. Perhaps you could ask Ford how these vehicles can be operated in Third World countries - their competitors, especially the Japanese seem to manage perfectly well.
659.
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659
I appreciate your comments, however since having my own problems I have been researching what problems other people have been having. In addition to problems with Ford engines there are lots of reports of problems with Peugeot and even Kia diesel engines. In fact if you look at this months Car Mechanics magazine (I was tipped off about this on another forum) you will see an article saying that there have been many problems with Siemens diesel pumps fitted to Peugeot and Kia, and some Kias have failed at as little as 20000 miles, like my Mondeo. The cost of repair on a Kia can be as high as £4000. I am now definitely of the opinion that unless one drives astronomical mileages the risk of having a diesel engine is not worth the candle.
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