Modern diesel engines - are they worth it??

gyppo

Just wondering what peoples views are on this.

Practically all of the current diesel engined cars available today offer superb fuel ecomony and performance. However, they also can cost a very significant amount of money when things go wrong, and one bill could wipe out any savings in fuel accrued over its ownership.

Things that are costly that immediately come to mind are
Common rail fuel pumps
Injectors
DM flywheel
Particulate filters

These going wallop are all fine and dandy if its a newish car covered by warranty - a sore dose though if its your own car you have owned for a few years and you're on your own.

How many people have pondered on going back to a less complex petrol engined car after owning a diesel?

Plug

I'd never buy a diesel for that reason. Now Ford's new petrol eco boast engines have some of these things on them, direct injection, turbo's etc. I can see them being a disaster.

ottostreet

I'm reluctant to go for anything that isn't N/A petrol these days.

Nice & simple is best. Hopefully the obsession with economy and 'greenness' will pass eventually.

iphone4g

ottostreet wrote: »

Hopefully the obsession with economy and 'greenness' will pass eventually.

Like that's going to happen,It's only going to get worse.

johnos1984

Plug wrote: »

I'd never buy a diesel for that reason. Now Ford's new petrol eco boast engines have some of these things on them, direct injection, turbo's etc. I can see them being a disaster.

They also have a DMF

I think we will just have to hope that as time goes by this technology becomes more reliable

vectra

johnos1984 wrote: »

They also have a DMF

I think we will just have to hope that as time goes by this technology becomes more reliable

Whats the story with DMF ?
Why do they go and is there a driving pattern to help avoid this pitfall?

johnos1984

vectra wrote: »

Whats the story with DMF ?
Why do they go and is there a driving pattern to help avoid this pitfall?

No idea why they fail

I think its a mix of poor design and torgue wearing them out

The one we have is on a 1.6l 2007 Mondeo so its not given any problems

M cebee

agree -based on my experience

these things are very temperamental and cost a fortune if the computer can even diagmose problem correctly

i had a van with 14k miles (out of warranty)-main dealer wanted 2k for injectors

after i traded it they told me it was a loose wire:(

Jimmy Garlic

Old skool diesel engines were infinitely more reliable, toyotas 2.0 indirect injection TD springs to mind, nothing really goes wrong with them. Some modern diesels are an expensive nightmare to own.

iphone4g

johnos1984 wrote: »

No idea why they fail

I think its a mix of poor design and torgue wearing them out

The one we have is on a 1.6l 2007 Mondeo so its not given any problems

The reason a lot of them fail is people driving diesel cars the same way they drove their petrol engined cars,ie high revs (not needed with diesel)and being very rough on gear down changes .

It's the application of the torque that is the problem(bad driving)

bonzodog2

johnos1984 wrote: »

They also have a DMF

I think we will just have to hope that as time goes by this technology becomes more reliable

Why does a petrol engine need a DMF ?

johnos1984

bonzodog2 wrote: »

Why does a petrol engine need a DMF ?

No idea but lots of them nowadays do

They fail on cars driven very sedately too so I doubt the driving style has much to do with it really in many cases, inherent design (or conception if you like) failure me thinks, many folk don't drive the ass off their car, don't use engine braking and don't rev a car hard. They won't fail as much on petrol cars as there is less vibration.

I Was VB

Jimmy Garlic wrote: »

Old skool diesel engines were infinitely more reliable, toyotas 2.0 indirect injection TD springs to mind, nothing really goes wrong with them. Some modern diesels are an expensive nightmare to own.

Have to agree, brought my 1994 Corona 2.0Diesel down to Galway for the weekend went down and back on the same tank, not to shabby for a car with 406K Klms!

mickdw

ottostreet wrote: »

I'm reluctant to go for anything that isn't N/A petrol these days.

Arent the bog standard bmw 320i pretty troublesome too with crazily expensive repairs required in many cases.

Ive had 2 turbo petrol audis now, one bought with 100k on clock and another bought new in 2008 and they have been faultless as far as engine/running goes.

kermitpwee

I Was VB wrote: »

Have to agree, brought my 1994 Corona 2.0Diesel down to Galway for the weekend went down and back on the same tank, not to shabby for a car with 406K Klms!

I'm a fan of carina's but that was only about 260 miles or so. how are the diesels compared to the 1.6 mpg wise?

-Corkie-

I Was VB wrote: »

Have to agree, brought my 1994 Corona 2.0Diesel down to Galway for the weekend went down and back on the same tank, not to shabby for a car with 406K Klms!

Neighbour had a 84 Corona donkeys ago she was some car.

OP their is no real reason for a DMF to fail the same as the injectors.

shawnee

iphone4g wrote: »

The reason a lot of them fail is people driving diesel cars the same way they drove their petrol engined cars,ie high revs (not needed with diesel)and being very rough on gear down changes .

It's the application of the torque that is the problem(bad driving)

That's seems to me a lot of rubbish, I have driven diesels for the last twenty years and driven most models without encountering engine problems. It is only in the last six or seven years that these engines seem to be creating problems. Water pums /particulate filters/Dmf's etc. Granted the modern diesels are faster but very few of them will go the 300/400k that the merc, peugeot,volkswagen diesels of the 80s and 90s did.
If they are not up to diffferent styles of driving then they are not worth the money.

TheAnswer

I heard (I've no idea how true it is or if it's just the start of a new urban myth) that the "stop/start" feature becoming increasingly common drastically shortens the life of the engine because the oil is not being continuously pumped around. It's probably bullsh1t but makes a mockery of manufacturers trying to squeeze an extra mpg out just to make good headlines if the engine is knackered after 100k km.

iphone4g

shawnee wrote: »

That's seems to me a lot of rubbish, I have driven diesels for the last twenty years and driven most models without encountering engine problems. It is only in the last six or seven years that these engines seem to be creating problems. Water pums /particulate filters/Dmf's etc. Granted the modern diesels are faster but very few of them will go the 300/400k that the merc, peugeot,volkswagen diesels of the 80s and 90s did.
If they are not up to diffferent styles of driving then they are not worth the money.

Thats your opinion ,but tell me when most people switched from petrol to diesel(i think it was in the last 6 or 7 years)

Nonoperational

I don't kno. I think the DMFs have to be susceptible to the very high torque delivered at very low revs, and some aspect of how people drive them. I have seen the same diesel engines have the DMF go at 50k and others still going strong at 150k (alfa/fiat 1.9 jtd). Similar on the vags. Some go early others last long into the 100k mark.

Petrols do seem to last longer for sure. A lot of Vags have turbo petrols with no DMF problems. They're a frustrating technology.

Plug

johnos1984 wrote: »

No idea why they fail

I think its a mix of poor design and torgue wearing them out

The one we have is on a 1.6l 2007 Mondeo so its not given any problems

They don't have one afaik. I've done a few clutches on them and never came by one. Its hardly an option?

johnos1984

Plug wrote: »

They don't have one afaik. I've done a few clutches on them and never came by one. Its hardly an option?

I doubt it as its an LX new model Mondeo

The clutch was making a funny noise and my mother asked me to take it to the garage to have it checked. The mechanic told me it was a fitted with a DMF and that the noise was just a trait. As it was all ok other than that I was happy enough to leave it

Now when I say noise I could barely hear it but it was irritating the mother who is deaf

johndaman66

iphone4g wrote: »

Thats your opinion ,but tell me when most people switched from petrol to diesel(i think it was in the last 6 or 7 years)

Doesn't necessairly mean quality and longevity didn't take a downturn in and around the same time frame either though. A damn lot of people were buying houses at the same time and even borrowing to the hilt to buy second houses and apparently it was a great thing to be doing at the time many would have you believe. The sheeple are not always right.

Leonard Hofstadter

Plug wrote: »

I'd never buy a diesel for that reason. Now Ford's new petrol eco boast engines have some of these things on them, direct injection, turbo's etc. I can see them being a disaster.

Turbo engines have been around for donkeys years in both petrol and diesel engines, and even with Irish maintenance failure is quite low.

Some engines have problems with them but that is down to bad design rather than turbos being problematic in the way Dual Mass Flywheels are just works of the devil.

Some very high specific output turbos can give trouble, but most don't.

What would concern me far more than a turbo being bolted onto an engine is direct injection in petrol engines.

Direct injection petrol engines do not like being driven sedately around town for too long - otherwise they will suffer from carbon build up. That said, there are products that can decoke engines in a matter of minutes, so it really shouldn't be a major worry.

DMFs work perfectly well with petrol engines - BMW petrol engines have had DMFs for at least the last 15 years and I have never heard of DMF failure with a petrol engined BMW (I have heard of lots of other things failing on modern BMW's, but DMFs on their petrols is not one of those things!).

I think the problem with DMFs is they are designed to smoothen out the vibrations of an engine, and diesel engines are nothing like as smooth running as their petrol engined counterparts, diesel engines put DMFs under far greater strain than petrol engines do.