Modern diesel reliablity

[Ferg]

We run a '51' 1.9 JTD and it's been fine. Two belt tensioners, but great on the injection side.

[Monkeylegend]

2002 C Class 220Cdi 160k miles in 2 years with no problems.

2003 E Class 220Cdi 320k miles in 3 1/2 years with no problems.

2007 E Class 220Cdi 205k miles in 3 years with no problems and still running well.

All serviced on schedule at MB main dealer and mostly motorway miles.

Diesels unreliable? Not in my experience.

Look after them and they will look after you.

[Rich_W]

jamieboy said:

flakeypaul said:

Isn't the rule with a DPF just to make sure that you allow the exhaust gas to become hot allowing the particles that have collected in the filter to be burned up or are there other issues?

That's the only issue I've heard of. If it doesn't get hot enough to burn the residue then it can clog and (on Alfas, anyway) the engine goes into a limp-home mode and sometimes stays there until you take it to the dealer for them to do a manual re-gen. I think different systems work in different ways, so that might not be true for all of them.

I'm sure I read that VW were not recommending DPF-equipped cars if you mostly did town driving, which seems to miss the point by quite a long way.

Pretty much. Which on VW's case is odd as the Blue motion cars are DPf equipped. And most of those live in towns/cities.

Can't speak for Alfa, but with VAG stuff. First the DPF light comes on, then the Engine light as well, then the car restricts performance. In an ideal world the customer would take the car for a 30-60min constant speed drive at around 2,500rpm and the car would "Regenerate" the DPF. Essentially it gets the exhaust gas so hot that it burns the soot in the DPF away. However, most customers either have no concept of how to do that or they simply cannot do the long drive. So the normal situation is they go to the dealer when they lose power. Depending on how much soot is in the DPF depends on whether it can be forced to regnerate by a technician and a computer (which incidentally is easier as it gives you the exact figures and we charge hour or 2 for labour to do this) or if its too full. You need a new one. And that's £1500. I predict that in 5-6 years cars will need them replacing anyway.

Great bit of design

[emicen]

Rich_W said:

jamieboy said:

flakeypaul said:

Isn't the rule with a DPF just to make sure that you allow the exhaust gas to become hot allowing the particles that have collected in the filter to be burned up or are there other issues?

That's the only issue I've heard of. If it doesn't get hot enough to burn the residue then it can clog and (on Alfas, anyway) the engine goes into a limp-home mode and sometimes stays there until you take it to the dealer for them to do a manual re-gen. I think different systems work in different ways, so that might not be true for all of them.

I'm sure I read that VW were not recommending DPF-equipped cars if you mostly did town driving, which seems to miss the point by quite a long way.

Pretty much. Which on VW's case is odd as the Blue motion cars are DPf equipped. And most of those live in towns/cities.

Can't speak for Alfa, but with VAG stuff. First the DPF light comes on, then the Engine light as well, then the car restricts performance. In an ideal world the customer would take the car for a 30-60min constant speed drive at around 2,500rpm and the car would "Regenerate" the DPF. Essentially it gets the exhaust gas so hot that it burns the soot in the DPF away. However, most customers either have no concept of how to do that or they simply cannot do the long drive. So the normal situation is they go to the dealer when they lose power. Depending on how much soot is in the DPF depends on whether it can be forced to regnerate by a technician and a computer (which incidentally is easier as it gives you the exact figures and we charge hour or 2 for labour to do this) or if its too full. You need a new one. And that's £1500. I predict that in 5-6 years cars will need them replacing anyway.

Great bit of design

Well, it kind of is actually. You get to fluff your dealer network and people are becoming more and more receptive to taking the hit with big bill if it saves the Polar Bears.

No doubt independants will make a killing out of it too when they have a cheaper replacement or figure out how to declog the old ones so do them on an exchange basis.

[OnTheOverrun]

Rich_W said:

jamieboy said:

flakeypaul said:

Isn't the rule with a DPF just to make sure that you allow the exhaust gas to become hot allowing the particles that have collected in the filter to be burned up or are there other issues?

That's the only issue I've heard of. If it doesn't get hot enough to burn the residue then it can clog and (on Alfas, anyway) the engine goes into a limp-home mode and sometimes stays there until you take it to the dealer for them to do a manual re-gen. I think different systems work in different ways, so that might not be true for all of them.

I'm sure I read that VW were not recommending DPF-equipped cars if you mostly did town driving, which seems to miss the point by quite a long way.

Pretty much. Which on VW's case is odd as the Blue motion cars are DPf equipped. And most of those live in towns/cities.

Can't speak for Alfa, but with VAG stuff. First the DPF light comes on, then the Engine light as well, then the car restricts performance. In an ideal world the customer would take the car for a 30-60min constant speed drive at around 2,500rpm and the car would "Regenerate" the DPF. Essentially it gets the exhaust gas so hot that it burns the soot in the DPF away. However, most customers either have no concept of how to do that or they simply cannot do the long drive. So the normal situation is they go to the dealer when they lose power. Depending on how much soot is in the DPF depends on whether it can be forced to regnerate by a technician and a computer (which incidentally is easier as it gives you the exact figures and we charge hour or 2 for labour to do this) or if its too full. You need a new one. And that's £1500. I predict that in 5-6 years cars will need them replacing anyway.

Great bit of design

Big problem here on the Isle of Wight. I had a previous runabout for local stuff and carrying the dog which rarely went onto the mainland. DPF played up every month. Sold it for a Fiat Doblo with the Fiat/Alfa/Vauxhall 1910cc diesel engine but with the 105bhp output with a fixed rather than variable turbo and no DPF. Three years later, never had a problem and has never returned less than 51mpg. Diesel turbos are great until you try to get too much specific output from them and then they get more and more fragile IMHO.

[leginlb]

So, having read this thread with interest, is the general agreement that earlier 'modern' diesels, e.g. VAG 110 / 115 tdi's, PSA 90 tdi's (306 D Turbo for instance) are best for DIYers, sheds, snotter use and the up to date stuff (PD, HDi, TDCi etc)only suitable for 'company' car use or those with deep pockets?

The reason i ask is I'm in the market for a cheap Diesel and have been looking at Passats with the PD engine, from what I've read on here that engine is a bit of a 'mare? Am I better off with the earlier generation?

[Jasandjules]

leginlb said:

So, having read this thread with interest, is the general agreement that earlier 'modern' diesels, e.g. VAG 110 / 115 tdi's, PSA 90 tdi's (306 D Turbo for instance) are best for DIYers, sheds, snotter use and the up to date stuff (PD, HDi, TDCi etc)only suitable for 'company' car use or those with deep pockets?

The reason i ask is I'm in the market for a cheap Diesel and have been looking at Passats with the PD engine, from what I've read on here that engine is a bit of a 'mare? Am I better off with the earlier generation?

Have an older Passat with a PD115 engine - I got her at 60k and she now has 130k, and I've had very few problems at all, though the alternator went a month or three ago. One of the little boxes went a couple of years ago (air flow) and it was less than £100 to fit.

[HellDiver]

Nothing wrong with PD engines, just avoid the 150hp 1.9, the later 1.9PD with the DPF, and the early 140hp 2.0TDI PD as they suffer porous heads.

The 130PD is considered the best of the bunch. Just use the correct oil (505.01), and make sure the belts are done in time, and you'll have an engine that will long outlast the car.

[csampo]

I had an VAG 1.0 130PD and it was excellent. A bit gruff, but it was quite muscular and never gave any trouble.

[Ayahuasca]

Submerged my Toyota Prado diesel (3 litre turbo) in a river the other day, water up to (but just under) the air intake, so basically completely submerged with engine off for about two hours.

Got it out of river, water poured out of exhaust and everywhere else, started at first attempt and ran sweetly, drove it home. Try doing that with a petrol engine!

[OnTheOverrun]

Ayahuasca said:

Submerged my Toyota Prado diesel (3 litre turbo) in a river the other day, water up to (but just under) the air intake, so basically completely submerged with engine off for about two hours.

Got it out of river, water poured out of exhaust and everywhere else, started at first attempt and ran sweetly, drove it home. Try doing that with a petrol engine!

I hate to break it to you, but a couple of hours submerged is more likely to do long term damage to a modern diesel than a petrol. If even a drop of water has entered the fuel system you could be looking at fuel pump, injectors etc, etc. A petrol will conk out, but once dried out it is less likely to be damaged long term. I've usually off-roaded with Rover V8's which are decent in water with a proper snorkel, sealed dizzy and plug-top carrots but when they do conk, a quick pull of the plugs and spin on the starter to empty the cylinders and a quick drain of the SU's and you're on your way with just enough time to brew up!

PS - I hope I'm being pessimistic and your motor is fine!

[mybrainhurts]

TheCarpetCleaner said:

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.

If an injector's gone, the engine switches to limp mode, with the power turned down.

I've done 265,000 in one. Bought at 6 months old, 6000 miles.

Injectors cost more than £300 at a dealer, but an independent's reconditioned is £200.

I had one go at about 198,000 and a second one at 263,000.

The independent who diagnosed the first one said the other three were also about to fail. They've done another 66,000 without failure, bar one. So, beware of dishonest independents.

Clutch, at nearly 200,000 was £750 from a transmission specialist.

[Ayahuasca]

OnTheOverrun said:

Ayahuasca said:

Submerged my Toyota Prado diesel (3 litre turbo) in a river the other day, water up to (but just under) the air intake, so basically completely submerged with engine off for about two hours.

Got it out of river, water poured out of exhaust and everywhere else, started at first attempt and ran sweetly, drove it home. Try doing that with a petrol engine!

I hate to break it to you, but a couple of hours submerged is more likely to do long term damage to a modern diesel than a petrol. If even a drop of water has entered the fuel system you could be looking at fuel pump, injectors etc, etc. A petrol will conk out, but once dried out it is less likely to be damaged long term. I've usually off-roaded with Rover V8's which are decent in water with a proper snorkel, sealed dizzy and plug-top carrots but when they do conk, a quick pull of the plugs and spin on the starter to empty the cylinders and a quick drain of the SU's and you're on your way with just enough time to brew up!

PS - I hope I'm being pessimistic and your motor is fine!

So far, so good (it was about three weeks ago)!

There was a LOAD of water in the fuel system a few months ago (garage sold me a tankful of contaminated diesel) but there is a 'water in fuel' warning light and you just pump it out of the separator.

[bodhi]

We've had about 12 BMW's in the family now and the only one that's given us an eye-watering bill was our 1999 320d. It had the original 137bhp engine, but at around 120k decided it wanted to grenade its' turbo and a couple of injectors. I believe the total bill came to around 3.5k.

So when it came to sourcing my own BMW I went for a 328i. I don't really do enough miles to justify a diesesal, and apart from the VANOS there is a hell of a lot less to go wrong under the bonnet.

[Fire99]

It's all about balance IMO. Diesel's have become far more technical (with the potential for expensive repairs) since the demand for more HP and cleaner emissions.
Plus, if I remember correctly, they inherently have relatively low CO2 output compared to an equivalent petrol engine. With the world's Governments obsession with CO2 then we have huge development in diesel technology.

Peronally I think most modern diesels are great day-to-day engines for normal cars. They're smooth, lots of torque for the dual carriageway and pretty impressive MPG if you aren't heavy with your right foot.

However, if I was paying with my own money, i'd be very concerned with buying a mid+ mileage second hand modern diesel. I'm not saying they're all guaranteed to cost big bills but the risk is great enough to seriously consider the possibility when laying out your own cash.

[mat205125]

Monkeylegend said:

2002 C Class 220Cdi 160k miles in 2 years with no problems.

2003 E Class 220Cdi 320k miles in 3 1/2 years with no problems.

2007 E Class 220Cdi 205k miles in 3 years with no problems and still running well.

All serviced on schedule at MB main dealer and mostly motorway miles.

Diesels unreliable? Not in my experience.

Look after them and they will look after you.

I think that this best sums up the position with diesel cars.

In the past a diesel engine built up a reputation for being bullet proof, and capable of relatively galactic mileage whilst the contemporary petrol motor's life was limited to 100k max typically. They built a reputation that they could take anything, and suffered all manner of neglect and abuse, and came back fighting.

A modern diesel is still capable of delivering reliable economy over amazing mileages as Monkeylegend proves above, however it is far more important to stick to the correct service schedule to maximise the car's lifespan, and avoid unforseen large bills.

On a personal note, I have driven, enjoyed, and been amazed by the economy of the large six pot BMW diesels in the past when managers had them, however also recall a number of these cars having a good deal of warranty work undertaken relating to turbos and injection systems. I've also got a friend who has had to through no end of cash at his 150bhp MK4 Golf TDi over the course of the time that he has owned it ..... For me, the return in the savings at the pump cannot offset the scary proposition of a looming catestrophic kick in the wallet that an out of warrenty modern TDi could give.

[HellDiver]

mat205125 said:

A modern diesel is still capable of delivering reliable economy over amazing mileages as Monkeylegend proves above, however it is far more important to stick to the correct service schedule to maximise the car's lifespan, and avoid unforseen large bills.

Sweeping statement. Some modern diesels fail regularly due to inherant faults in the emission controls.

[mat205125]

HellDiver said:

mat205125 said:

A modern diesel is still capable of delivering reliable economy over amazing mileages as Monkeylegend proves above, however it is far more important to stick to the correct service schedule to maximise the car's lifespan, and avoid unforseen large bills.

Sweeping statement. Some modern diesels fail regularly due to inherant faults in the emission controls.

This thread is full of statements that could be described as sweeping, and points of view based on different experiences by different people.

Not a single person has managed to report an independent, unbiased, statistical analysis of the probability of failure of parts of, or entire, modern diesel and petrol engines.

I repeat, however, that I wouldn't want to put my own money into an unwarrentired car.

[HellDiver]

mat205125 said:

Not a single person has managed to report an independent, unbiased, statistical analysis of the probability of failure of parts of, or entire, modern diesel and petrol engines.

I suggest you go and look at any Astra or Vectra forum and check out the thousands of threads about failed inlet manifolds on the Z19DTH engine.

Or go to any Ford forum and check out the injector failures on the 2.2TDCI.

How about Merc ceasing production of their latest CDI engine for months upon months due to injector faults?

There are plenty of modern diesels with faults that regularly occur no matter if they're serviced or not.

Edited by HellDiver on Tuesday 1st June 09:21

[The Wookie]

havoc said:

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.

Eh???

You'd expect an engine with different fuel, different method of ignition and completely different cylinder head design to behave in the same way just because the injector is in the cylinder?