Diesels, the potential hidden cost

Stallingrad

It's increasingly well documented that modern diesels carry with them certain issues that may well offset any tax and mpg gains that are currently the key appeal.

So for the uninitiated here some of the main issues you should be mindful of before choosing diesel. Bear in mind you may or may not be affected by any of these problems depending on what kind of driving you do, how gentle you are with you car, the make and model, etc.

DPF problems:
A diesel particulate filter (or DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine
Failure of fuel injectors or turbochargers resulting in contamination of the filter with raw diesel or engine oil can also necessitate cleaning.
Vehicles driven exclusively at low speeds in urban traffic can require periodic trips at higher speeds to clean out the DPF.
If the driver ignores the warning light and waits too long to operate the vehicle above 40 miles per hour, the DPF may not regenerate properly, and continued operation past that point may spoil the DPF completely so it must be replaced.
A failed DPF can cost you at least €500 before fitting with prices rocketing from there.
Car dealers very rarely will warn you of the consequences of short journeys and low speeds, be warned.

EGR
The EGR valve helps your car more efficiently burn fuel by recirculating a portion of your exhaust and running it through the combustion process again.
This decreases you car's noxious emissions by prohibiting the formation of some harmful gases.
When the EGR valve goes bad, it must be cleaned or replaced.
It is not uncommon for EGR valves to get completely gummed up after a few years with carbon deposits which results in poor running.

DMF
A dual mass flywheel is designed to help smooth out the torque produced by petrol and diesel engines, providing less vibration and easier gear changes.
The greater torque of diesel engines stresses the DMF to greater extent than a petrol engine, as a result DPF failures are more prevalent in diesel engines.
DMF's are much more expensive to replace than a standard flywheel and clutch.
Some DMF's can be replaced with a cheaper single mass flywheel, but this option is dependent on model and not a very common practice.
If your DMF goes you could be looking at around €1000 from an Indy or up to €2000+ from a main dealer.
Failures have been noted at anything form 40,000 miles upward, to get 100,000 out of a DMF is good going but not unheard of.
Based on the above you could keep in mind that it could be costing you €200-€400 a year to cover any future DMF failures.

So do your homework, Google this stuff. Petrol engines are getting cleaner and more efficient and in many cases may be a better and cheaper option depending on your usage.

The intention here is not to scaremonger, but forewarned is forearmed.

Bigcheeze

Not another evil diesel thread. For what it's worth the only mechanical problem I've had in a 6 year old petrol passat is the EGR needing to be replaced after about 50,000 miles.

bladespin

Been done a few times already, the problem isn't with the cars, more the people who buy them and don't use them as intended.

mickdw

Certainly, failures of the items listed are at a level now on so many diesels that they need to be factored in much the same as basic service costs as they will happen.
I figure if buying a used diesel and you intend to do 25k miles + per year, you could budget for one of the above failures each year.

mickdw

bladespin wrote: »

Been done a few times already, the problem isn't with the cars, more the people who buy them and don't use them as intended.

Thats bull crap when talking about DMF.

bladespin

mickdw wrote: »

I figure if buying a used diesel and you intend to do 25k miles + per year, you could budget for one of the above failures each year.

I'd be amazed by that, been driving diesels for the past decade plus at over 40k miles per year and haven't had any of the above.

bladespin

mickdw wrote: »

Thats bull crap when talking about DMF.

How many DMF failures have you had?

Henry Ford III

EGR's and DMF's are not unique to diesels.

dgt

Apart from an EGR I don't have any of those or any major electrical nonsense on the 406, hence why I picked it

dgt

Henry Ford III wrote: »

EGR's and DMF's are not unique to diesels.

Both of which are in my Alfa 166, petrol

BostonB

Henry Ford III wrote: »

EGR's and DMF's are not unique to diesels.

Isn't DMF failure not more likely on a diesel due to the torque?

reilig

Doing 40 to 50 k miles per year on a diesel for the last 8 years and have not had to replace, repair of even clean any of the above.

delynet

The EGR one is an interesting one for me. Have an 02 A4 with close on 200,000 miles (bought with 54,000). About 60,000 miles ago I had problems when trying to accelerate, no power. Eventually power would kick in and a load or black smoke\soot would come out the exhaust

Changed the EGR valve and all was fine for about two weeks and it started again. Mechanic disconnected it and its been that way for 2 years, passed two NCT's in the process.

cadaliac

reilig wrote: »

Doing 40 to 50 k miles per year on a diesel for the last 8 years and have not had to replace, repair of even clean any of the above.

What do you drive? Do service regularly and/or change your car often? That is big mileage.

BostonB

Do diesel and petrol EGR have the same problems?

whippet

Stallingrad wrote: »

Car dealers very rarely will warn you of the consequences of short journeys and low speeds, be warned.

When I bought my superb combi the Skoda dealer actually gave me a full A4 Sheet explaining the DPF with illustrations of the warning lights and before giving me the keys asked me to sign the form to indicate that I understood what he was talking about.

I'm 37k miles on after 16 months of owner ship and no issues at all.

mullingar

whippet wrote: »

I'm 37k miles on after 16 months of owner ship and no issues at all.

37k in 16 months? You wont have any problems of DPF blockages as you are driving as intended.

Its the folks who do 10k/year, mostly city driving, that it will bite as they are not doing enough motorway runs for the DPF to regenerate

MuppetCheck

reilig wrote: »

Doing 40 to 50 k miles per year on a diesel for the last 8 years and have not had to replace, repair of even clean any of the above.

Many of these parts are not applicable to older diesels. If it is the same car it could be possible that you do not have some of these.

If it is a newer car it is very probably that you wont have many issues with a diesel. Your mileage implies longer distance driving which is ideal for a diesel engine. I am in a similar situation to you and I drive a mile to the motorway and spend the next hour on it followed by fast flowing national roads. There is little use of the clutch, the exhaust system bolt-ons are working in optimum conditions. I dont expect many problems in the future.

Blazer

whippet wrote: »

When I bought my superb combi the Skoda dealer actually gave me a full A4 Sheet explaining the DPF with illustrations of the warning lights and before giving me the keys asked me to sign the form to indicate that I understood what he was talking about.

I'm 37k miles on after 16 months of owner ship and no issues at all.

fair play to him...he's definitely in the minority.

mickdw

bladespin wrote: »

How many DMF failures have you had?

I dont drive a diesel so DMF is unlikely to fail in mine however, brothers 05 octavia failed 60k miles. Other brothers passat failed at 22k and 70k having bought it new. Sisters vectra failed at 35k. Only other diesel car in the family is another diesel passat. This has not yet failed at 50k miles.

Leonard Hofstadter

Henry Ford III wrote: »

EGR's and DMF's are not unique to diesels.

DMF failure is unique to diesels though:)! As you correctly say, lots of petrol engined cars have DMFs, but because petrol engines are so much smoother running than diesels, the DMF is under far less stress in a petrol engined car, therefore it is far less likely to fail.

Where To

Have 157000 miles on a superb. Cleaned EGR at 100000 miles and put in solid flywheel at 110000.

Dont see any hidden costs in that.

jsd1004

Where To wrote: »

Have 157000 miles on a superb. Cleaned EGR at 100000 miles and put in solid flywheel at 110000.

Dont see any hidden costs in that.

DMF's are fitted for a reason. Solid flywheels can cause other problems as they allow vibration to pass through other components such as crankshaft and gearbox. A friend has a 08 A4 with 85kmiles which has eaten its swirl flaps egr and fan in the last year. Total bill of about 4k of which Audi paid 700. Service intervals of 18k certainly contribute to this.

jprboy

jsd1004 wrote: »

DMF's are fitted for a reason. Solid flywheels can cause other problems as they allow vibration to pass through other components such as crankshaft and gearbox. A friend has a 08 A4 with 85kmiles which has eaten its swirl flaps egr and fan in the last year. Total bill of about 4k of which Audi paid 700. Service intervals of 18k certainly contribute to this.

So are shorter service intervals to be recommended?

Leonard Hofstadter

jprboy wrote: »

So are shorter service intervals to be recommended?

Yes, anything more than 20,000 km on the same oil is madness, even if it is approved by the manufacturer. The only reason this is done is because most cars that size are company cars, so long service intervals enable the manufacturers to claim that the car is 'cheaper' to run for the fleets, all it's doing really is pushing the problems down the line to when the cars are out of warranty.

bladespin

mickdw wrote: »

I dont drive a diesel so DMF is unlikely to fail in mine however, brothers 05 octavia failed 60k miles. Other brothers passat failed at 22k and 70k having bought it new. Sisters vectra failed at 35k. Only other diesel car in the family is another diesel passat. This has not yet failed at 50k miles.

Wow, I'd be asking VAG for new cars TBH, no idea about the Astra, we have 5 passats at well over 100k (miles each) without a failure, a golf on over 180k (kms) still going strong.

Historically for me the only real issues I've experienced is clutch failure on a Trooper (180k miles so can't complain - flywheel was changed as a precaution), 60k miles in a Landcruiser, no issues, 30k miles+ in a Mondeo (injectors failed but it was an issue on that model - risk taken, bad choice), 40k miles in an Alfa without issue. The Golf still runs like a good un.

jsd1004

bladespin wrote: »

Wow, I'd be asking VAG for new cars TBH, no idea about the Astra, we have 5 passats at well over 100k (miles each) without a failure, a golf on over 180k (kms) still going strong.

Historically for me the only real issues I've experienced is clutch failure on a Trooper (180k miles so can't complain - flywheel was changed as a precaution), 60k miles in a Landcruiser, no issues, 30k miles+ in a Mondeo (injectors failed but it was an issue on that model - risk taken, bad choice), 40k miles in an Alfa without issue. The Golf still runs like a good un.

As my dad used to say to me about electric windows...'just another thing to go wrong' All the technology in cars these days is great and enhances safety, driver comfort and performance. However if any of these systems go wrong they are going to need to be fixed and more than likely its going to be expensive. All cars including petrols are getting hideously complex and are going to be very difficult to keep maintained as they age. New tri-turbo engines,supercharging and turbocharging together, high pressure injectors,dmfs, egrs and all sorts of sensors airbags and complex ecus to keep emissions down and performance up. There may be hope for the electric car yet.

bladespin

jsd1004 wrote: »

There may be hope for the electric car yet.

Hmmm, wonder how much an electrical engineer charges per hour, remember these aren't for the local indy, you'll need a password to open the bonnet.

ofcork

I assume dealers as in the post above will have to explain the DPF to people,even the new avensis is advertised as having a dpf.

Sobanek

We (as the family) own a 2006 v50 diesel, 2 litre. Only thing that went is the EGR valve. All the rest is ok. 125k kms today.

vectra

mullingar wrote: »

37k in 16 months? You wont have any problems of DPF blockages as you are driving as intended.

Its the folks who do 10k/year, mostly city driving, that it will bite as they are not doing enough motorway runs for the DPF to regenerate

25k kms on my one after almost 2 years.
Majority of it stop start.

How many CR VAG engines have you come across with failed DPF's ?

JJJJNR

244,000km on my 05 2.0 TDi no big bills, gets a dash of diptane every fill and an oil+filters change every 10,000km, gearbox oil every 100,000km etc still getting great mileage out of it and very happy.

Suffers from a lumpy idle when cold since I bought it with 30k on and hasn't got any worse or better so just live with it.

Bpmull

captainspeed wrote: »

Yes, anything more than 20,000 km on the same oil is madness, even if it is approved by the manufacturer. The only reason this is done is because most cars that size are company cars, so long service intervals enable the manufacturers to claim that the car is 'cheaper' to run for the fleets, all it's doing really is pushing the problems down the line to when the cars are out of warranty.

We service our skoda Octavia 1.6 tdi every 15k km. as far as I know the book recommends 30k km. all the skoda garages recommend 15k km. so that's when we get it done. I think 30k would be way to long not to change oil even if its long lasting oil.

Bpmull

JJJJNR wrote: »

244,000km on my 05 2.0 TDi no big bills, gets a dash of diptane every fill and an oil+filters change every 10,000km, gearbox oil every 100,000km etc still getting great mileage out of it and very happy.

Suffers from a lumpy idle when cold since I bought it with 30k on and hasn't got any worse or better so just live with it.

My Megane 1.5dci has the same lumpy idle we were told it was to do with injectors. But it doesn't get any worse and you only feel it when the car is idling but you just get us to it. The car is 2004 so it's not worth changing injectors unless they fail.

Gru

Hey guys,

I'm interested in buying a newish car and was looking at something like a Focus diesel, maybe 2009 or newer but I'm unsure if it's worth looking at all. The weekly driving I'd be doing with the car is mainly to work and back which is about 16-17Km each way with longer drives at weekends touring around a bit with the family and take on any of the longer journeys that might crop up.


Would this be enough mileage to avoid blocking up the DPF, based mainly on the monday to friday work routine?

Thanks

Katunga

Stallingrad wrote: »

Failures have been noted at anything form 40,000 miles upward, to get 100,000 out of a DMF is good going but not unheard of.

Thats Bull I no plenty of people to put over 200k miles on a DMF.

sean1141

Gru wrote: »

Would this be enough mileage to avoid blocking up the DPF, based mainly on the monday to friday work routine?

Thanks

A 15 min blast in 4th gear on the motorway once a month sould be enough to clear out the dpf. They just need to be givn the chance to clean out. This most likely wont happen with town drivng

Katunga wrote: »

Thats Bull I no plenty of people to put over 200k miles on a DMF.

Over 100k miles on both my leon and bora without any dmf bother. It was replaced at 160k in m mondeo

September1

bladespin wrote: »

Hmmm, wonder how much an electrical engineer charges per hour, remember these aren't for the local indy, you'll need a password to open the bonnet.

There are significantly less elements and they are much simpler, additionally there is less vibration and heat in the system. Even if you are charged 1000/h it still is cheaper to replace exhaust, EGR, DPF in EV than ICE ;-)

bladespin

September1 wrote: »

There are significantly less elements and they are much simpler, additionally there is less vibration and heat in the system. Even if you are charged 1000/h it still is cheaper to replace exhaust, EGR, DPF in EV than ICE ;-)

I've heard batteries quoted at north of €5k+, AFIK they're quite easy to feck up too as are the inverter and control systems.

Popoutman

captainspeed wrote: »

Yes, anything more than 20,000 km on the same oil is madness, even if it is approved by the manufacturer. The only reason this is done is because most cars that size are company cars, so long service intervals enable the manufacturers to claim that the car is 'cheaper' to run for the fleets, all it's doing really is pushing the problems down the line to when the cars are out of warranty.

The underlined is completely untrue.
If the oil in an engine is manufactured to the manufacturer's requirements (e.g. VW 505.01, 506.01, or 507.00 for the Pumpe Deuse tdi engines), and the oil is replaced at the required interval either by the normal-interval (1 year / 10,000 km) or the extended service interval, then the engine will not have problems. The additives to the oil to ensure that the oil meets the required standard will keep the oil working.

Did you know that there is a conductivity meter in the VAG diesels that measures the dissolved metals in the oil? Did you also know that the ECU can calculate the expected performance of the oil given the use pattern that the engine has seen on that oil? In other words the engine can determine itself when the it's oil is nearing it's useful life. The problems can happen when the driver continues to drive for a few thousand kilometres over the change interval.

Personally, I've had the oil in my 2002 A4 1.9 tdi engine analysed at 24,000 kms since previous change. The onboard indicator was for the change to be done in 2000km time. The analysis came back with a note that the oil while not performing as new was still *well* above the requirements needed for the engine, even accounting for the requirements for the PD cam lobes. I've had the rocker cover off to check the injector wiring loom in the head and there was no appreciable wear on any of the cam lobes - so on my engine at least there isn't a problem with the extended service. It's worth noting though that I was driving 15k-25k per year so I was ending up with an oil change about once a year. Now that my driving requirements have changed, I'm still doing an oilchange once a year, based on time not distance.

That 2002 Audi is currently on 302,000kms..

September1

bladespin wrote: »

I've heard batteries quoted at north of €5k+, AFIK they're quite easy to feck up too as are the inverter and control systems.

Batteries are not that easy to break, actually previous generation is now over 10years old and most of batteries lost capacity but did not malfunction. I did not hear about inverters and control systems failures in production cars being much of problem, but please share your sources.

jsd1004

September1 wrote: »

Batteries are not that easy to break, actually previous generation is now over 10years old and most of batteries lost capacity but did not malfunction. I did not hear about inverters and control systems failures in production cars being much of problem, but please share your sources.

Batterys are pretty foolproof, they do lose capacity over time but so does IC. Even at 5k for a battery over a lifetime as a worst case scenario thats pretty cheap considering a DMF and clutch can cost 3k at a dealer.

JJJJNR

Popoutman wrote: »

I've had the rocker cover off to check the injector wiring loom in the head and there was no appreciable wear on any of the cam lobes - so on my engine at least there isn't a problem with the extended service.

How did you do this, or did you get someone to do the work.

bladespin

September1 wrote: »

Batteries are not that easy to break, actually previous generation is now over 10years old and most of batteries lost capacity but did not malfunction. I did not hear about inverters and control systems failures in production cars being much of problem, but please share your sources.

Sources of what, I've used several manufacturer's inverters and they're for the most part quite similar in both function and design.

Control systems are simply eelectronic boards that usually use the same power-source as the machine itself and are therefore vulnerable to surging etc. (I've built and burnt my fair share lol).

Anyone who's had a few mobile phones over the years will understand my comment about batteries, they're basic but efficiency can be affected by not charging in the correct manner, at such a massive price I'd be wary and NO, I'm not slagging off the electric car just pointing out that just like their aspirated counterparts there could be an expensive repair bill hidden in there.

A DMF and clutch for €3k, sounds massively overpriced.

Popoutman

JJJJNR wrote: »

How did you do this, or did you get someone to do the work.

Did it myself.

The reason for opening things up: I had a misfire and down on power. So I attached VAG-Com, saw a misfire code and saw that the injection volume balancing done at idle was lots out and not working properly. I did a bit of research and had a chat with the local VAG dealer and they confirmed that the injector wiring loom can sometimes get broken insulation on very high mileage PD engines, and causes the symptoms I was seeing. The dealer said that the replacement was an engine-out job as the loom comes out at the rear of the head and there isn't enough clearance to get the straight loom into the head. I disagreed After a bit more research and chatting with others that had performed the same repair, I got the replacement loom, stuck it in the oven at about 85 degrees until the loom carrier became pliable. While I was waiting for the loom to bake I took off the rocker cover, and easily enough took the old loom out though it was brittle and the wire insulation was also brittle. Putting the new loom in was interesting as the loom carrier was hot and bendy, and I had a limited time to play with, but it went in first time and without an issue. Reattached everything and the car fired up fine, and no new codes were thrown after the codes from the repair itself were cleared. The single biggest problem was accessing one of the rocker cover bolts near where the inlet manifold passes the rocker cover as my socket sets didn't have hte articulation needed.

When the rocker cover was off, all of the lobes were accessible so I was able to look closely at and feel across the lobe tips for pitting or significant wear but there wasn't any wear - the shiny part was level with the non-contact point. Rocking the car in gear allowed me to see all of the cam lobes.

That was 2 years and 30,000km ago, and no problems since.

Total time under the bonnet was less than two hours, and with the right tools it should be possible to have the rocker cover off and back on within half an hour.

gammygils

Never owned a diesel. But was thinking about it with the rising cost of petrol. Only do about 13-15k a year. I'll stick with petrol

Thanks for the info