The real facts about DPFs.

NIMAN

I have found out a few details about these things on this MOTORS forum, since I became interested a couple of years ago after buying my 1st diesel car.

Thing is, I am still slightly confused, as I read that I should be grand with mine as I drive it a good 45 mile round trip 5 days per week.

However I was chatting to a car salesman today and he was actually upfront about DPF problems, saying that they have to tell people about them on their 2nd hand cars, as they can often end up coming back complaining about warning lights/problems. He told me its not long journeys at 60mph that will help, but high revs, advising me to stick it in 3rd and drive it for 5miles with the revs up, and that will burn off the soot.

So what are the facts, because to be honest when I chat to diesel car owners I work with, very very few even know what a DPF is and how much it could cost them. Many of these drivers commute maybe less than 10mile to work, some only a couple of miles.

I'd love to know the real answers to these questions:

1) What is the likelihood of a failure?
2) What are the % fails among each model sold?
3) If a warning light comes on, is that it? Buggered, or will a quick run in 3rd gear for 5mins sort it out?
4) Why is the problems of DPFs not better known? I have read hundreds of car reviews over last few years, and many recommend, for example, getting the 1.6 diesel instead of the 1.8 petrol, but I don't ever remember one single review mentioning a potential costly problem in the future.

So are people being sold a pup? Should car salesmen ask people what sort of driving they are doing before advising what car might be best for them? Should car magazines tell us about a potential costly bill? After all, nearly everyone I know only buy diesels now.

Outkast_IRE

Im not too knowledgeable either on the failure rates etc.

But yes in my opinion plenty of people are being sold cars which ultimately wont suit their usage patterns and can potentially cost them big in the long run.
Alot of these people would be better off with petrol ultimately, and i think you may see a gradual return to people buying petrols as more economical petrol engines come out like Fords 1.0L turbo petrol etc.

Blazer

Stick it in 3rd and drive with the revs up?:eek:
the safest best is to find your nearest motorway, put the foot down around 120kph for about 10 miles or so and you should be sorted.
On my car I notice a burning smell after the dpf has regenerated and it's rumoured that the recycle time for a BMW DPF is engine must be 75c or hotter, revs above 3,000, travelled at least 10 miles at those revs and then will it kick it.
I have seen it kick in when I've pushed it hard around back roads and rapid breaking and accelerating but I won't be too gone on this 3rd gear ****e for 5 miles.

kona

Some trucks recommend 3k revs for 20 mins. Redline being 5k. I doubt a 5 min blast a gear lower on the motorway would do it.

MuppetCheck

Most cars should be fine at about 2k revs for 20 minutes. 3k revs is a bit excessive, especially when most modern diesels sit at around 2k at 120 meaning you need to be in 4th to achieve that.

Failures are going to become more common as the cars age. Some systems are better designed and more tolerant than others. Prices should also drop in the coming years with familiarity.

YbFocus

Just pull the bloody things out, saves all this hassle.

MuppetCheck

YbFocus wrote: »

Just pull the bloody things out, saves all this hassle.

I guarantee in the not too distant future it will be a requirement for the nct that if one was originally fitted in the car it will need to be present and correct unfortunately.

YbFocus

Well if they do that then I've had it
Silly things all they have done is cause hassle since they turned up!

166man

MuppetCheck wrote: »

I guarantee in the not too distant future it will be a requirement for the nct that if one was originally fitted in the car it will need to be present and correct unfortunately.

I'd doubt that and although I can see a dpf becoming a NCT requirement, I'd imagine it will only apply to new cars sold or whatever. It's legal and so easy (relatively) to remove the DPF so they can hardly show up in a few years and say you should have one... Not feasible IMO..

Marcusm

166man wrote: »

I'd doubt that and although I can see a dpf becoming a NCT requirement, I'd imagine it will only apply to new cars sold or whatever. It's legal and so easy (relatively) to remove the DPF so they can hardly show up in a few years and say you should have one... Not feasible IMO..

Not that hard in reality; since 2011 all new cars have had to meet Euro V emissions standards which, for diesels, basically means having a DPF fitted. Adding a particulates emissions test for post 2011 cars or for cars which had them fitted as standard kit would not be difficult. CO emissions are included in the test already and particulates (basically soot) are a big contributor to asthma.

166man

Marcusm wrote: »

Not that hard in reality; since 2011 all new cars have had to meet Euro V emissions standards which, for diesels, basically means having a DPF fitted. Adding a particulates emissions test for post 2011 cars or for cars which had them fitted as standard kit would not be difficult. CO emissions are included in the test already and particulates (basically soot) are a big contributor to asthma.

I was more referring to how they introduce this for people who have had their's removed etc. I do see them becoming a requirement alright but not that if the car came with one it should be present.

Ronnie Beck

They need heat from your exhaust to regenerate. Your exhaust is hottest not neccesaily at high rpm but under load or during hard acceleration. DPF were origanally fitted to large vehicles such as trucks which were constantly under load so produced high exhaust gas temperatures. For example if you going downhill at 120 with your foot feathering the accelerator your egt's are relatively low. A WOT your EGT's will remain fairly constant right through the rev band.

The only thing that increases with RPM is the rate of flow of air through the exhaust system. I don't know how significant that is to regeneration. I also don't know whether for DPF's the hotter the EGT the better or if it has an optimum burn off temperature...

Ronnie Beck

good video on exhaust systems

http://www.youtube.com/watch?v=fNO-oUHmKXU

DanielGibbons

Ronnie Beck wrote: »

good video on exhaust systems

http://www.youtube.com/watch?v=fNO-oUHmKXU

Very good, cheers for sharing

MuppetCheck

166man wrote: »

I'd doubt that and although I can see a dpf becoming a NCT requirement, I'd imagine it will only apply to new cars sold or whatever. It's legal and so easy (relatively) to remove the DPF so they can hardly show up in a few years and say you should have one... Not feasible IMO..

It's completely feasible. They are required to meet Euro V and Euro VI regulations and this requirement has already been introduced in the UK.

166man

MuppetCheck wrote: »

It's completely feasible. They are required to meet Euro V and Euro VI regulations and this requirement has already been introduced in the UK.

So anyone who had a DPF in their car and got rid of it for whatever reason - cost, annoyance etc will now have to pay to get one put back on their car to pass an NCT? I can't see that going down well tbh...

MuppetCheck

Who knows what they decide on the start date, I'd imagine it will be from when they became compulsory if they were to do it. All I'm saying is it may not be the ideal solution it's made out to be so worth keeping that in mind before removal.

Elessar

Just get it removed. It won't be a problem with the nct. When the uk mot "introduced" this it was just a visual inspection of the exhaust system. Loads of reports of people passing without problems with removed dpfs. No emissions tests for diesels. You'll be fine.



Exactly what I'm planning when I get my new diesel car this week (well, after the warranty is up). I only do very low mileage. But I love the torque of the diesel. Will bring it for a good spin once every week or two til then.

Marcusm

166man wrote: »

I was more referring to how they introduce this for people who have had their's removed etc. I do see them becoming a requirement alright but not that if the car came with one it should be present.

But can't you see that what you're suggesting would be a bit silly; "we require these to be fitted to cars but you can remove it if you want". Certainly the history of those type of features on cars, whether they be seatbelts, rear seat belts, passenger side mirrors etc is that if they came as standard kit, sooner or later a rule is introduced to require that they not be tampered with. Surely you can see that if it's decided that it is necessary to have one on the car so that it meets the requirements to be sold means that at some stage it's quite likely that the ongoing road worthiness test would incorporate a means to ensure that it remained present?

A comparator might be to say that we have a right to establish that you are a competent driver before you get a licence but we (the state) has no right to reassess or enforce compliance with road safety rules later.

Anan1

166man wrote: »

So anyone who had a DPF in their car and got rid of it for whatever reason - cost, annoyance etc will now have to pay to get one put back on their car to pass an NCT? I can't see that going down well tbh...

Just like with cats.

Michael8000

I'm in the market for a second hand diesel car and as usual mileage is a concern but after reading this am I maybe looking at it the wrong way? I'm looking at 2007 models. Would a mileage of 50k miles be too low for an approximately 6 year old car? About 8,500 miles per year? Or am I interpreting this incorrectly?

listermint

Michael8000 wrote: »

I'm in the market for a second hand diesel car and as usual mileage is a concern but after reading this am I maybe looking at it the wrong way? I'm looking at 2007 models. Would a mileage of 50k miles be too low for an approximately 6 year old car? About 8,500 miles per year? Or am I interpreting this incorrectly?

8,500 Miles per year. Dont buy a diesel!!

Michael8000

listermint wrote: »

8,500 Miles per year. Dont buy a diesel!!

Sorry maybe I wasn't clear. I'm doing 20k miles a year. I meant the diesel car I've seen was doing an average of 8,500 miles a year.

listermint

Michael8000 wrote: »

Sorry maybe I wasn't clear. I'm doing 20k miles a year. I meant the diesel car I've seen was doing an average of 8,500 miles a year.

got ya, does it have a DPF not all models had them in 2007.

bring it to a reputable dealer for inspection. but yes to answer your question the mileage is very little for a DPF but that does not account for how the previous owner drove it when they did have it out.

For instance my friends mother has a focus with a DPF and she drives like miss daisy and does less than 6000 Miles annually. The car was completely inappropriate for her day to day. So he borrows it for the long haul trips and gets it up to tempreture every now and again. alas thats no guarantee of long life for the DPF but its the best they can do given the situation short of selling it (which would be a better choice)

Michael8000

listermint wrote: »

got ya, does it have a DPF not all models had them in 2007.

bring it to a reputable dealer for inspection. but yes to answer your question the mileage is very little for a DPF but that does not account for how the previous owner drove it when they did have it out.

For instance my friends mother has a focus with a DPF and she drives like miss daisy and does less than 6000 Miles annually. The car was completely inappropriate for her day to day. So he borrows it for the long haul trips and gets it up to tempreture every now and again. alas thats no guarantee of long life for the DPF but its the best they can do given the situation short of selling it (which would be a better choice)

It's a 520D. Would they have a DPF?

Anan1

Michael8000 wrote: »

It's a 520D. Would they have a DPF?

Have a look at the exhaust pipe, if it's angled downwards then it's the 163bhp model and doesn't have a DPF.

Michael8000

Anan1 wrote: »

Have a look at the exhaust pipe, if it's angled downwards then it's the 163bhp model and doesn't have a DPF.

Yes it would be the 163bhp model I would be after anyway for various reasons.

C Eng

Michael8000 wrote: »

Yes it would be the 163bhp model I would be after anyway for various reasons.

163 bhp does have a DPF

mullingar

MuppetCheck wrote: »

I guarantee in the not too distant future it will be a requirement for the nct that if one was originally fitted in the car it will need to be present and correct unfortunately.

Marcusm wrote: »

Not that hard in reality; since 2011 all new cars have had to meet Euro V emissions standards which, for diesels, basically means having a DPF fitted. Adding a particulates emissions test for post 2011 cars or for cars which had them fitted as standard kit would not be difficult. CO emissions are included in the test already and particulates (basically soot) are a big contributor to asthma.

Just like Petrol cars, I reckon that the future NCT test on diesels will only check exhaust content , not on what components are in the car, eg the DPF, (which is just a glorified soot filter, and does nothing for the harmful NOx content)

With a petrol, as most know, they have the CO and HC tests which fail if any of the emission control devices, eg the Cat or O2 sensor are on their way out.

For diesels, they will reduce the soot test from IMO an excessively high pass rate of 3.0 to maybe 0.5, or lower. The wifes 1.6 Focus has the DPF removed and Mr. NCT reported back a soot level of just 0.1, thats 1/30th the fail level.

The NCT may bring in NOx testing, or not, but either way a DPF will not affect the CO or NOx values

Anan1

C Eng wrote: »

163 bhp does have a DPF

I'm almost 100% certain that it doesn't.

C Eng

Anan1 wrote: »

I'm almost 100% certain that it doesn't.

Well it does

Anan1

C Eng wrote: »

Well it does

Any chance of a link?

Max Power1

C Eng wrote: »

Well it does

Wow you have convinced me 100% with that argument. FACHT!

C Eng

Max Power1 wrote: »

Wow you have convinced me 100% with that argument. FACHT!

Well done for your valuable input. Now what do you want Pictures?

Anan1

My understanding is that the DPF was available as an option on the 163bhp M47, and was standard on the 177bhp N47. The M47 without DPF is recognizable by the tailpipe being angled down towards the road.

C Eng wrote: »

Well done for your valuable input. Now what do you want Pictures?

A link to a source backing up your contention would be good.

Max Power1

C Eng wrote: »

Well done for your valauble input. Now what do you want Pictures?

A link
To back up your to date invalid statement

mullingar

Anan1 wrote: »

Have a look at the exhaust pipe, if it's angled downwards then it's the 163bhp model and doesn't have a DPF.

Michael8000 wrote: »

Yes it would be the 163bhp model I would be after anyway for various reasons.

C Eng wrote: »

163 bhp does have a DPF

Anan1 wrote: »

I'm almost 100% certain that it doesn't.

C Eng wrote: »

Well it does

Max Power1 wrote: »

Wow you have convinced me 100% with that argument. FACHT!

C Eng wrote: »

Well done for your valuable input. Now what do you want Pictures?

It does, and you can buy them off ebay for every 2.0 version, the 150hp, 163 AND 177hp

http://www.ebay.co.uk/itm/BMW-5-Series-520d-Replacement-Diesel-Particulate-Filter-DPF-New-/310597641061?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Cars+Type%3A520d&hash=item48510fe365

and a quick google pulls up these links:



Edit:

Further googling shows that some early 320D's with 163hp had no DPF and later ones did, all 177hp have DPF.

milltown

The IMO is strong in this thread.

renofan

The only input I can add is that because of DPFs I stick to petrol cars

Anan1

mullingar wrote: »

Edit:

Further googling shows that some early 320D's with 163hp had no DPF and later ones did, all 177hp have DPF.

We have a Feb 07 build 320d in the family (so a late 163bhp) and that has no DPF. It was an option.

jemmyboy

The light came on for my DPF during the week. Drive an Audi A3 1.9 TDI. Going to get it taken out coz the car has gone into limp mode :-(. They are a nuisance of a thing!

TheBazman

I've an 07 e60 and had my first dpf warning at 230k kms. After a few temporary fixes it turns out that the car needs to be above a certain temp to regenerate the dpf which mine wasn't achieving. We replaced the thermostats and problem solved.

Capri86

Thanks for posting that video. Very informative.

I've had no problems as of yet with the DPF on my s40. I reckon I only do around 12k a year which everyone says is not enough for a diesel, but it's 90% motorway miles. I'm hoping it'd enough for regeneration to occur

Anan1

Capri86 wrote: »

I reckon I only do around 12k a year which everyone says is not enough for a diesel, but it's 90% motorway miles. I'm hoping it'd enough for regeneration to occur

I can't see how the annual mileage could matter, as long as the conditions for regen are being met.

Capri86

Anan1 wrote: »

I can't see how the annual mileage could matter, as long as the conditions for regen are being met.

That's exactly it. But a common response to lower mileage on boards is don't buy a diesel.

I'm not saying I won't have dpf issues though. It's very hard to know

sofitalliah

Capri86 wrote: »

That's exactly it. But a common response to lower mileage on boards is don't buy a diesel.

I'm not saying I won't have dpf issues though. It's very hard to know

Agreed its nanny style driving that clogs them up too and the same rule goes for the DMF.

Anan1

sofitalliah wrote: »

Agreed its nanny style driving that clogs them up too and the same rule goes for the DMF.

To be fair, I'd imagine that even short runs driving like Senna wouldn't work either.

Capri86

What I think is a huge factor in all this is the annoyance of having an instantaneous fuel consumption read out in the dash. People are obsessed with keeping consumption down and their driving has changed dramatically because of this by keeping revs as low as possible at all times. Wish my car didn't have that read out..

Bpmull

My focus 1.6tdci doesn't have a dpf so that's no harm although I mainly do long trips and little town driving anyway. My mother has her 1.6tdi octavia a few months of 2 years and has had no difficulty with it about 50k km on It I think I've heard it generate it once that's it. IMO a major problem which causes dpf failure is so many people buy diesels and just barely drive them changing every 2k rpm trying to save diesel. Diesels need to be driven on hard up through the gears every so often. I couldn't see my mothers car causing any dpf problems anytime soon. My uncle has 150k km on an original dpf in his car never had an issue with it.
The only situation I can see where a dpf would cause trouble is if the car was only doing town driving but then why someone would buy a diesel to only drive around town on short trips is beyond me.

Ronnie Beck

Capri86 wrote: »

... but it's 90% motorway miles. I'm hoping it'd enough for regeneration to occur

You could do 1000 miles a year and it would make no odds. DPFs don't block up if the car is sitting in the garage. It's short slow journeys that diesels hate. Even my van which has no DPF or Cat will be in bad humour if it's sitting in traffic for a few days. As said in the video if it's not burning fuel efficiently you get alot more soot build up.

I think some BMWs use the shot of diesel down the exhaust to clear the DPF located further down the exhaust- probably triggered on a pressure differential whereas the VAG tdi's and other BMW's have the DPF very close to the manifold so it's up to yourself to create high EGT's for it like this -



Be worth knowing what type of system you have on your own car

Ronnie Beck

Bpmull wrote: »

My focus 1.6tdci doesn't have a dpf so that's no harm although I mainly do long trips and little town driving anyway. My mother has her 1.6tdi octavia a few months of 2 years and has had no difficulty with it about 50k km on It I think I've heard it generate it once that's it. IMO a major problem which causes dpf failure is so many people buy diesels and just barely drive them changing every 2k rpm trying to save diesel. Diesels need to be driven on hard up through the gears every so often. I couldn't see my mothers car causing any dpf problems anytime soon. My uncle has 150k km on an original dpf in his car never had an issue with it.
The only situation I can see where a dpf would cause trouble is if the car was only doing town driving but then why someone would buy a diesel to only drive around town on short trips is beyond me.

Elderly folk beside me have a 2012 1.5dci Nissan for going to the shop. I wouldn't say it hits 2krpm. The salesman who sold them that should be shot. They probably paid a heap extra for it too.