Modern diesel reliablity

Modern diesel reliablity

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Discussion

phil_cardiff

Original Poster:

5,395 posts

177 months

Friday 28th May 2010
quotequote all
Parents are thinking of getting a modern common rail diesel. But their mechanic has told them that things like fuel pumps and injectors are super expensive and can fail due to the high pressures that theu work under.

Of course, any component of an engine can fail but are these modern diesels unreliable compared to petrol engines or is it all talk?

Thudd

3,100 posts

176 months

Friday 28th May 2010
quotequote all
Mate with a Mondeo TDCI keeps getting big bills. £500-1000 region. Injectors/inductors, EGR valve. <70,000 miles. Just out of warranty when it went pop.

thinfourth2

32,414 posts

173 months

Friday 28th May 2010
quotequote all
Wouldn't touch a modern turbo diesel with a barge pole unless doing silly milage.

Guy at work has a zafria just out of warranty that has blocked its particulate filter and is looking at a £1400 bill. and it was loads of hassle during the warranty period

soad

30,993 posts

145 months

Friday 28th May 2010
quotequote all
thinfourth2 said:
Guy at work has a zafira just out of warranty that has blocked its particulate filter and is looking at a £1400 bill. and it was loads of hassle during the warranty period
yikes How much?! That's crazy.

Dr G

14,201 posts

211 months

Friday 28th May 2010
quotequote all
Only if I was doing big miles, they are inherently more troublesome than petrol engines.

alephnull

347 posts

144 months

Friday 28th May 2010
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I would be surprised if modern diesels would be significantly more trouble. All modern manufacturers apply Taguchi design principles, so an engine block will be designed to have a failure rate of 0.001% over 10 years for 22 bar (if diesel) or 14 bar(if petrol) (note those figures are just examples). Basically, the designed failure rate should be the same regardless of the peak cylinder pressure or common rail fuel pressure.

HOWEVER, diesels are more likely to have turbos. Secondly, diesel components may cost more as they would be rated to deal with higher loads associated with CI.

Tyre Smoke

18,335 posts

230 months

Friday 28th May 2010
quotequote all
If modern diesels were so crap at reliability, why do all us taxi drivers use them?

I have a fleet of 407 2.0L diesels and they all have well over 100k trouble free miles on them - stop start town work as well as motorways. They all do circa 1500 miles a week and the oldest (55 plate) has 190k miles on it.

10 Pence Short

32,880 posts

186 months

Friday 28th May 2010
quotequote all
Tyre Smoke said:
If modern diesels were so crap at reliability, why do all us taxi drivers use them?

I have a fleet of 407 2.0L diesels and they all have well over 100k trouble free miles on them - stop start town work as well as motorways. They all do circa 1500 miles a week and the oldest (55 plate) has 190k miles on it.
I bet they're serviced properly. Unlike rather a lot of modern diesels, especially when they get into private hands.

Parrot of Doom

23,075 posts

203 months

Friday 28th May 2010
quotequote all
The only thing that matters is, are they doing enough miles per year?

If they're not, get a petrol.

Tyre Smoke

18,335 posts

230 months

Friday 28th May 2010
quotequote all
10 Pence Short said:
Tyre Smoke said:
If modern diesels were so crap at reliability, why do all us taxi drivers use them?

I have a fleet of 407 2.0L diesels and they all have well over 100k trouble free miles on them - stop start town work as well as motorways. They all do circa 1500 miles a week and the oldest (55 plate) has 190k miles on it.
I bet they're serviced properly. Unlike rather a lot of modern diesels, especially when they get into private hands.
Yes, they are. I agree, most people get a diesel and forget to look after them properly.

TheCarpetCleaner

7,294 posts

171 months

Friday 28th May 2010
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My mondeo TDCI, which I had from 8,000 miles at 1.5 years old, through to 130,000 at 5 years old, had no problems whatsoever during its working life, however towards teh end I had

Random misfire - Was told by diesel specialist it "might" be a misfiring injector. 1 injector = £200 recon or £300 new. May need all four replacing.

Clutch was starting to rattle = new clutch and Dual mass flywheel. Average quote based on 8 garages - £1000

So to suddenly get two simpleish problems on other cars that would cost £2.5k to get the whole lot done possible, thats quite harsh.

Modern diesels are great, until they have a mechanical fault.

edo

16,699 posts

234 months

Friday 28th May 2010
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Dr G said:
they are inherently more troublesome than petrol engines.


Swwwwwooooooooooooooooooosh (the noise of a sweeping statement)....


Back to the top

188 posts

138 months

Friday 28th May 2010
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I have no figures to back my opinion up but just from reading web forums , friends,family etc ,modern dervs are more or less as reliable than they were 10 years ago but when they do let go it's a large bill so it's publicised. They also need specialist attention when this happens , pre common rail / PD stuff was generally simple and robust rather than complex and robust . Fixed with a lump hammer rather than OBDII diagnostics if ghat makes sense .....

sonarbell

226 posts

136 months

Friday 28th May 2010
quotequote all
In the past 10 years Ive done half a million miles. All Vehicles serviced every 20k as per Vauxhall spec. All Vehicles reliable apart from :
1 off Alternator. (Warranty Item) 1st Astra Van
1 off Indicator Relay. 2nd Astra Van
1 off Dual Mass Flywheel. (Warranty. Common problem.) Vectra SRI CDTI (150BHP).

Oh and the regular failure of those crappy Philips Headlamp bulbs !!

All vehicles required no oil between service intervals and proved totally reliable.


flakeypaul

436 posts

159 months

Friday 28th May 2010
quotequote all
Tyre Smoke said:
10 Pence Short said:
Tyre Smoke said:
If modern diesels were so crap at reliability, why do all us taxi drivers use them?

I have a fleet of 407 2.0L diesels and they all have well over 100k trouble free miles on them - stop start town work as well as motorways. They all do circa 1500 miles a week and the oldest (55 plate) has 190k miles on it.
I bet they're serviced properly. Unlike rather a lot of modern diesels, especially when they get into private hands.
Yes, they are. I agree, most people get a diesel and forget to look after them properly.
In what way would you look after a diesel properly aside from sticking to the service schedule? I only ask as I'm about to buy my first 'modern' diesel and hope it will last! (I've previously owned a Pug 306 DTurbo but that engine was made of volcanic rock).

Tyre Smoke

18,335 posts

230 months

Friday 28th May 2010
quotequote all
Being taxis, I tend to use good quality oil and filters and reduce the service period from 20k to 15k.

To be honest, preventative rather than reactive maintenance is the answer. If a ball joint has play in it, but would be considered 'acceptable' in normal use, I replace it.

TheCarpetCleaner

7,294 posts

171 months

Friday 28th May 2010
quotequote all
Gaz. said:
Tyre Smoke said:
10 Pence Short said:
Tyre Smoke said:
If modern diesels were so crap at reliability, why do all us taxi drivers use them?

I have a fleet of 407 2.0L diesels and they all have well over 100k trouble free miles on them - stop start town work as well as motorways. They all do circa 1500 miles a week and the oldest (55 plate) has 190k miles on it.
I bet they're serviced properly. Unlike rather a lot of modern diesels, especially when they get into private hands.
Yes, they are. I agree, most people get a diesel and forget to look after them properly.
Both yourself and TheCarpetCleaner make valid but opposing points, do you follow the manufacturers specified maintenance schedule or do you improve on it? smile
Main dealer for first year at recommended intervals, then self serviced every 8000 miles using genuine ford parts in my case.

Fuel filter drained and cleared as per schedule.


Starfighter

3,874 posts

147 months

Friday 28th May 2010
quotequote all
Modern common rail systems and EUIs are much more reliable than the old pump and pipe systems. The materials and machining technology is much better and tolerances have to be held much tighter to have a chance of hitting the pressures involved. The increased pressures are there to give better atomisation and combustion control during the injection cycle / cycles. It's technology, don't be afread of it.

flakeypaul

436 posts

159 months

Friday 28th May 2010
quotequote all
Starfighter said:
Modern common rail systems and EUIs are much more reliable than the old pump and pipe systems. The materials and machining technology is much better and tolerances have to be held much tighter to have a chance of hitting the pressures involved. The increased pressures are there to give better atomisation and combustion control during the injection cycle / cycles. It's technology, don't be afread of it.
^^^^^^^^^^ more comments like this please ^^^^^^^^^^

Can you please now tell me that Renaults don't break, ever. Especially the diesels wink

havoc

26,205 posts

204 months

Friday 28th May 2010
quotequote all
flakeypaul said:
Can you please now tell me that Renaults don't break, ever. Especially the diesels wink
hehe

A modern CR TDi is a fair bit more complex than an n/a petrol, and the components are under more pressure and more stress. So I'd be very surprised if they last as long, or are as reliable. Finally, direct injection has been seen on the VAG FSi engines to coke-up the inlet tract and the back of valves a lot quicker. I'd expect the same in a diesel.

But the comment above about maintenance is also very important - and as someone said on a different thread, a lot of people now treat cars like white goods.

Personally I wouldn't get a modern TDi unless:-
- I did very big mileage; and
- I got a decent a/market warranty to cover the big stuff
...but they're still the best answer for 20k+ mileages.