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I suspect they are actually pretty reliable and the failure rate is low. The snag is that if you're unlucky and yours is one of the few that goes wrong then you're soon into four-figure sums. Even on something as mundane as a Ford I reckon the pump is around £800-900 from a dealer. Couple that with a dearth of technicians who can genuinely diagnose faults and its not a recipe for restfull sleep. I know I don't want to own one - even though I have a mate who's done all the Bosch training courses and bought himself a load of kit for diagnosis (he also has about 30 years experience as an independent).
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Like most electronic things these days if they do not go wrong in the first six months they will prpbably go on forever. ( well nearly). People said the same about fuel injection for petrol vehicles not all that long ago. Do we hear a great deal about that now?
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There is an order of magnitude difference in complexity between CRD and petrol injection. For a start most petrol injection systems work on pressure of 20-60psi. CRD's are up at 24,000psi+ !!!
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These pressures are way over anything that is used in aircraft SFAIK. In an aircraft hydraulic system you can make piping, overall, smaller if you use higher pressures. When I quit flying a typical hydraulic system pressure was 3000 psi and the very latest aircraft had 4000 psi. You can see that 24k to 30k psi is something really new and we don't have aircraft engineers dealing with them, just diagnostices and VERY expensive parts. After all they are being made to aircraft tolerances and more, and the price reflects this.
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Absolutely incredible pressures. As this technology is relatively new could we expect to see reliability increasing over the next few years?
I used to love my old xud diesel, but stories of very expensive failures on CRDs made me go petrol on my last purchase. Maybe i will go back to diesel in the future.
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Trying to compare common rail diesel to Aircraft hydraulic systems is separating things further than chalk or cheese.
Diesel fuelling systems, have relatively few connections, very short pipe runs, and apart from the pump nothing in the way of moving parts. (I suppose you could class the injectors as moving at a pinch)
An aircraft (commercial) hydraulic system on the other hand, has hundreds of metres of piping, diverters, accumulators, actuators, rams, and more junction and unions than you can shake a stick at.
But in the long run, Get used to it. You want a diesel you get a common rail cos that?s all that?s going to be available.
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TourVanMan TM < Ex RF >
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I was trying to draw a comparison rather make a direct statement. The point I was trying to make is that we have (probably) more common rail diesels around than there are aircraft hydraulic systems. The cars are running at 6 times the newest a/c system pressures, we don't have airlline style or standard of servicing so it isn't surprising that the car systems are a bit troublesome and very expensive to fix. I totally agree that the aircraft system is way bigger, thousands of moving parts and plenty of potential for trouble. I was just drawing attention to the huge pressures and high technology now seen in some cars.
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To give a comparison, .357" magnum pistol cartridges develop chamber pressures of 24,000 psi when fired, this is a measure of what common-rail design and materials have to stand up to, and why bits are not cheap.
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Aprilla, i think you may be confusing the TDDi pump with the TDCi pump. IIRC, the old mechanical distributor pumps were about £800, due to thier complexity, I think the new common rail pump is only about £200.
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I would be extremely surprised if any common rail pump was £200!!!
Add a zero on the end and that wouldn't be unusual for some.
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well my shower pump with a 1 bar pressure cost 200 quid.
You dont get 3000 bar pump for 200 quid.
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TourVanMan TM < Ex RF >
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My partner has a 1999 SAAB 9-3 Tdi and when it 'died' the other day a new SAAB pump was £1800, a refurb from them was £1500 and I got her original one rebuilt in Swansea for £900 with a 1 year warranty. That certainly wasn't a common rail pump - just very expensive!
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I have done 108,000 in my TDCi, even if it needed an extra £1500 spent on it now over and above what 2.0 petrol would require I would still be a grand better off accounting for running costs.
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I have done 108,000 in my TDCi, even if it needed an extra £1500 spent on it now over and above what 2.0 petrol would require I would still be a grand better off accounting for running costs.
Yes, for the majority of owners they make that kind of economic sense. But what about the guy who had a major failure at 3.5 years old and 40k miles! It is a bit of gamble - much more so than with a petrol car.
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At that annual mileage a diesel doesn't make economic sense anyway. I'll grant you the pump failure thing makes it a lot worse, but...
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Aprilla, i think you may be confusing the TDDi pump with the TDCi pump. IIRC, the old mechanical distributor pumps were about £800, due to thier complexity, I think the new common rail pump is only about £200.
Don't think so! Not from Ford anyway!
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When the cambelt went on my 1.8D Fiesta (1996 vintage - no CR then!) there was a possibility the distributor pump could have been damaged. A replacement back in 1998 was £600. Fortunately it was OK.
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I have absolute respect for Aprilia.
I am an Engineering Manager at a Power Generation company and have been a Mechanical Engineer for over 25 years.
I can honestly say that i read virtually all of Aprilia's posts and have yet to find fault in anything he says.
I therefore have a very simple question for you Aprilia.
If you were in the market for a new mass produced family saloon; ie Mondeo, C5, Vectra, Mazda 6, Laguna, Accord Primera, Avensis etc. .....what would be your first choice? (and why would you chose it?)
cheers
Trev
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He definitely wouldn't have the C5 or Laguna...
My guess is the Avensis.
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There's currently a Xantia HDi on ebay that's covered more than a quarter of a million miles.....so they can last! My feeling is that the biggest killer of CR injection systems is mis-fuelling.
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RichardW
Is it illogical? It must be Citroen....
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I suspect the Japanese (and Honda in particular) would not have developed common rail diesels if there were inherent reliability issues. Japanese R&D and QA processes border on the obsessive (I work for a Japanese IT hardware company and I've seen it first hand).
I would put good money on anything with a Honda badge covering 200,000 miles with only trivial faults if properly looked after and serviced, and I wouldn't expect the CDTi range to be any different.
Cheers
DP
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There are only a few supplilers of CR Diesel systems (Delphi, Denso, Bosch) and most vehicles will use one of these systems, with some modification for the particular application. Denso are possibly the leaders - having introduced CR for big Hino truck engines. The recent Denso systems run at about 1800bar (27000psi) and use piezo injectors which are more precise than the solenoid type - Denso have a big factory in Hungary which supplies European assembly plants. I'm not certain who Honda use, but I would think it would be Denso. The Delphi and Bosch systems look very similar to me - so maybe Delphi license some of the technology from Bosch?
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Not sure they have much choice. With the ever tightening emmision regulations and efficiency requirements, it would appear that common rail or individual pumped injectors (VAG PD) are the only ways to control the combustion process with sufficient accuracy. Common rail is also gradually appearing in other diesel applications such as trains.
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Correct me if I am wrong, but doesn't the Mondeo 2.0 TDCI use a Delphi system whilst the stablemate X Type 2.0 diesel use Denso due to issues with the Mondeo system?
BTW, Passat Tdi pump was £500 reconditioned and about £1k for a new one if my memory serves me right. Don't Toyota exclusively use Denso for there diesel range?
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Denso was once part of the Toyota company, hence the close links.
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Correct me if I am wrong, but doesn't the Mondeo 2.0 TDCI use a Delphi system whilst the stablemate X Type 2.0 diesel use Denso due to issues with the Mondeo system?
No, they use the same system, the system in both was revised to meet Euro IV.
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Correct me if I am wrong, but doesn't the Mondeo 2.0 TDCI use a Delphi system whilst the stablemate X Type 2.0 diesel use Denso due to issues with the Mondeo system?
Yes, this is true. I don't know a great deal about these systems, but my friend who repairs them reckons that Denso is the best and far more reliable than Delphi. Delphi systems are cheaper but appear to be less reliable - they are used on a wide variety of vehicles, inc. some Far Eastern marques such as Kia and Hyundai. He's had to repair a number of Kia and Hyundai CRD Diesels (e.g. the Sedona and 4x4's) at around 50-60k miles with faulty pumps and injectors, not to mention Fords. Its always hard to know if they've been misfuelled, but on the other hand he tells me he's hardly ever had to lay a spanner on a Denso system.
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I therefore have a very simple question for you Aprilia. If you were in the market for a new mass produced family saloon; ie Mondeo, C5, Vectra, Mazda 6, Laguna, Accord Primera, Avensis etc. .....what would be your first choice? (and why would you chose it?) cheers Trev
I don't think any of these cars would be a let-down. They all have good handling, road-holding, brakes etc and good comfort and safety features. I would have concerns about the reliability of the French cars (reliability is a 'zero'th order' requirement for me). Ditto the Vectra - although it is one of the quietest and best long-distance motorway cruisers IMHO. The Mondeo is a good car, but I have some reservations about its long-term robustness (I have seen a few with poor paintwork and even rust!). Primera, Toytota, Accord and Mazda6 would all do the job - it then comes down to styling and price. If price were not a major issue then probably the Honda.
The family car I personally WOULD buy is not on your list though. Its the Subaru Legacy. The reasons... top drawer engineering, fit and finish; rugged and reliable mechanical parts, super handling, 5-star safety (inc. US NHTSA 'gold award' for front and side impact), not overpriced- not only that but non-turbo Subarus are actually reasonably spacious under the bonnet and due to the flat-four layout any minor repair work (sensor replacement etc) is relatively simply (if you have a pit or ramps). Downsides to Subaru ownership are higher than average fuel consumption and rather expensive parts (and hence also insurance). Automatic versions are not all that great due to the rather jolty Suby EAT 'boxes - so stick with a manual.
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You are possibly correct to have concerns about the reliabilty of the French cars Aprilia. I currently own the C5! However its not been at all bad; there were a few recalls during the first 6 months of ownership, but since then its settled down nicely and ive done 42,000 trouble free miles.
Interesting to hear your views on the Subaru. In fact i looked at one just 2 weeks ago as it was at the top of my list of cars to try ,but ruled it out on the comfort score due to the 45% aspect ratio tyres. Youre right about the standard of engineering though; its superb.
Good to hear your views on the Mondeo too. One thing my Citroen will not do is rust. Look at all the 12 year old Xantias that are still cruising around. Not a blemish to be seen on their paintwork.
Drove the Honda 2.2 diesel last weekend. Had leather seats ....looked just like plastic. Well made plastic though!
Might have to take a chance and go for another C5 HDI
Cheers
Trev
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Aprilia,
Thanks for your answer to happytorque's question, which I found interesting.
If I might ask a supplementary, since this thread is supposed to be about CR diesels, . . .
If you were going to buy a Honda Accord, would you go for the diesel, or one of the petrol engines - and why?
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Regardless of marque it's currently diesel every time for me. I do 20,000 miles a year, but even if it was less I still prefer the driving characteristics of a diesel. They do cost more to buy, but I notice my trips to the fuel station more than I notice a few extra quid on a loan every month. I currently get mid 40s average mpg without having to consider my driving style, with a petrol of equivalent performance it would be 30 if I drove very carefully, but mid 20s would be more realistic.
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Perhaps we should wait for the long-promised Subaru diesel - I think this would clinch it for me. (Due next year, I believe?)
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Personally I would only buy a Diesel on economic grounds - i.e. work out the 'break even' mileage point where it is cheaper to run a Diesel and then add 10%, say, and if I'm doing more than that annual mileage then go for the Diesel. I can see the point of buying a Diesel if you only do a low annual mileage - I actually prefer a petrol engine. I did a couple 100's miles in a new Vectra 1.9CDTi with auto the other day. At 60mph it was ticking over at 1500rpm in top - so an incredible long-distance cruiser. However in urban driving there was a pronounced throttle 'lag' when pullling away from rest and so I really didn't enjoy driving it that much. I like smooth and revvy petrol engines like the Hondas, Mitsubishi & Nissan V6's etc. The Suby's rev well too.
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Thanks Aprilia
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I only do 9K a year and still have a diesel. I find driving a petrol quite tiring now, since you have to use the gears more. In my diesel I just push the loud pedal more.
Of course if you really enjoying your motoring to the exent that reving an engine quite hard and changing gear is your idea of fun, then a petrol is probably a better option. But I just like to get in and drive.
I am yet to be convinced that there is going to be some kind of problem a few years down the road with all these CR diesels. Cars have been getting progressively more complex for years now, I am sure the same arguments were aired when cars went onto fuel injection instead of carbs, ABS became more common etc. etc.
CR technology has been around for a while now (8 years maybe??) I am sure any significant problems would have reared their ugly head by now.
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.I am yet to be convinced that there is going to be some kind of problem a few years down the road with all these CR diesels. Cars have been getting progressively more complex for years now, I am sure the same arguments were aired when cars went onto fuel injection instead of carbs, ABS became more common etc. etc.
Well, I'm old enough to have been around when the first wave of mass-produced petrol fuel injection cars hit the market (I'm thinking K-, KE-, L-, LH- as opposed to D-Jetronic). Anyway, when we had to start fixing those all we needed was some basic technical information, a decent digital muitimeter and a pressure gauge reading up to 100psi. To get really clever all you needed was a 'scope to monitor sensors and injection pulse width etc. Even if we did something wrong there was little chance of killing anything. When closed-loop emission control came in (lambda sensors) all it needed was a little more understanding of the system and latterly, of course, some form of scan tool.
CR Diesels, as has been oft repeated, are of a different order of magnitude in complexity. The overwhelming majority of garages don't have the equipment to do even the most basic checks. The correct equipment is expensive and, I suspect, unlikely to drop much in price. Moreover relatively few technicians even understand the operation of CR, let alone have the ability to diagnose and rectify faults. Remember, complex injectors like the latest Denso's could be injecting a dozen individually timed pulses down to 0.1ms on each cycle for each cylinder! I'm sure that this is why so many faulty CR cars end up with a new pump and injectiors at £2k+ no one knows what else to do...BTW - these are not cars to play about on if you don't know what you're doing - its possible to inadvertantly hold an injector open and put loads of fuel into a cylinder - then bang!
Misfuelling is also a mjor problems which (IMHO) makes buying any used CR Diesel a bit of a gamble. Something needs to be done. I don't think we can rely on different filler nozzle designs etc etc - the CR system much protect itself - I would suggest some sort of 'fuel quality monitor' (possibly based on measuring the refractive index of the fuel, or its dielectric properties) to sense 'contaminated fuel' and immediately switch off the pump.
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Aprilia
I couldn't agree more. [And I can remember the points-triggered D-Jetronic! Even owned a CSL back in the '70s.] It's not only the complexity of these systems that taxes the repairers, it's also the massive variation between ostensibly identical cars. Just how many different versions are there of just the HDi in all it's guises? Fifty? A hundred? All with very different equipment and weaknesses to check - the data books are often worse than useless and without reliable data, accurate diagnosis is impossible - even for the few that can.
Idiot-level [and ever-growing] complexity, made of rubbish-quality components, working at the very limit of technology in a hostile environment; does not bode well for long life. High annual mileages don't seem to be a problem; ageing does. The sheer amount of fragile wiring [and associated connectors] essential to keep it all functioning, is proof enough that they're not going to make "old cars;" though the Japanese ones will have a definite advantage in that area. [Once Denso sort that pump issue out.]
Common-fail diesels are simply too much, too soon. With so many components to pay for, the temptation to source them at the lowest cost must be near-irresistible. This may be the root of one of the CR diesel's main problems - irritating, ill-defined niggles that defy any attempt to resolve them due to their tenuous nature and the horrific cost of replacing the doubtful parts. Once most CRs are four years old, one major failure kills them and they get sold "as is." I've even seriously considered the economics of scrapping a 14-month old Mazda 6 Est; it only got repaired by the skin of it's teeth. Although I own a couple of "simple but sophisticated" old diesels, I wouldn't have a CR one as a gift. It'd be like sitting on a ticking bomb and who needs that stress.
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>> I wouldn't have a CR one as a gift. It'd be like sitting on a ticking bomb and who needs that stress.
I really cannot understand that view, my TDCi has done 108k and drives like new, it has saved me a couple of grand over a petrol model so would have to cost a lot to repair for me to be in the red. Yes it could go kaput tomorrow though a failure is far less likely to be terminal than, for instance, a failure on my previous V6 Vectra that had four camshafts and two cambelts with numerous tentioners etc, I was very nervous in that within 10,000 miles of the 60k cambelt change. Likewise a contemporary belt driven Ford has a 100k recomended change interval however I could not drive a car with enthusiasm that had belt that had done much more than 60k without having to have something crossed.
The point is that there is no clear time/distance related impending failure on a chain cam CR diesel however you all drive belt cam petrol and diesel cars without a care.
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However in urban driving there was a pronounced throttle 'lag' when pullling away from rest and so I really didn't enjoy driving it that much. I like smooth and revvy petrol engines like the Hondas, Mitsubishi & Nissan V6's etc. The Suby's rev well too.
The only diesel I've driven that doesn't seem to suffer from this throttle lag is the VAG PD TDI unit. Now I'm not a VW fan particularly but I was blown away by the engine in my father in law's mk IV Golf TDI PD 130. It responds instantly to tiny throttle inputs just like a good petrol engine, and punchy doesn't even begin to do justice to its delivery. That said, you would never call it refined although, being able to pull away from day to day traffic without going much past 2,500 RPM helps a little.
In a sports car, I prefer petrol. However, in family/daily transport I'm starting to prefer diesels. I don't know if its because diesel engines seem to get better and better or petrol engines become more lacklustre with every new piece of emissions legislation or every 100kg extra of kerbweight they are forced to cope with as cars are updated and replaced. In the typical tonne and a half plus family car nowadays, diesels seem to cope a lot better.
But I agree a smooth, sweet petrol engine in a good chassis is still the sweetest driving experience in my opinion.
Cheers
DP
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"Once most CRs are four years old, one major failure kills them"
Yes, that's the nub of it, Screwloose.
I think CR Diesels are a good example of 'ignorance is bliss' - i.e. they are OK to own if you don't anything about them. If, like me, you know a bit (and no-way do I consider myself any sort of expert) then it all gets rather frightening and I just couldn't sleep if I had one on the drive - knowing that a misfire might cost as much to fix as taking a family holiday in Spain.
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Aprilia
What's a "holiday?"
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If you don't know then you're not charging enough ;-)
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Aprilia What's a "holiday?"
A special edition Ibiza?
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I agree with Cheddar. Having put up with cambelt failure on an older Diesel, I spent years worrying about cambelts. Now I buy chain cam diesels. It happens to be CR. Must I worry about that too?! Life's too short. Ignorance is bliss in my opinion. Please don't tell me what else can go wrong!!!!!
Perhaps I should stop reading these pages.............bad for my health...
Splodgeface
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