Do All Recent Diesels Have Potential Partic. Filt. Problems?

Whitespirit66

Whitespirit66

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Someone in the pub was telling me that their Jag needs £900 of work for a new particulate filter and associated components. I've also heard about big problems with filters on other recent diesels unless you take them for a blast on the motorway every week to clear them out.

My Scudo van is 10 years old and due for replacement. Are recent vans (and cars) all fitted with part. filters that need special attention or the potential to run up big bills when they go wrong? Are some makes/models worse than others?

It seems that running a diesel can often save on fuel, but you pay on higher purchase price, higher servicing costs, higher spares prices (friends derv Astra recently needed a £600 fuel pump - no used units available) and now expensive filters. Looking like, unless you do very high miles, petrol versions may be a better bet. Probably impossible with vans though.
 
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The cost of maintaining a diesel is can be an issue if you don't do many miles as they generally cost more and can be less reliable. If yours is driven fairly hard at least sometimes you shouldn't have to much DPF trouble, unfortunately I believe they all have DPFs now.

Second cars and those only used for shopping and school runs would be better petrol but if you are doing a fair mileage the diesel could save you money.

I run common rail diesels of the PSA Hdi variety and I must say mine have been very reliable, both have covered around 200,000 miles and are still going well but they don't have DPFs as they were an early engine.

Mine cost very little to repair as I get most parts from the scrap yard or ebay but if you have to pay for your repairs and you are buying new it needs some thinking about.

My cars are over 10 years old and you can buy them for peanuts so if you do get a serious problem you can throw them away and buy another one.

Peter
 
The DPF is just a fine filter, that clogs up with soot if it can't get hot enough.
If this is the case, it has to regenerate - in other words, made to get so hot that the soot burns away (back into the atmosphere).
The VAG group program their cars to stick at 3000 rpm to do just this, but in serious cases the DPF has to be replaced.
In other words, give your car a regular, fast run!
Unfortunately, diesels are being left behind on the reliability stakes, and the manufacturers have some catching up to do.
John :)
 
IIRC Jaguars - of the rebodied Ford Mondeo variety - use a special fluid to help clear the DPF that needs topping up ocasionally.
My VAG with a DPF is of the take it for a blast variety.

Word is in the new MOT test the tester is required to check for a DPF if the car is supposed to have one as standard and fail it if it doesnt.
Of course nothing to stop the unscrupulous from replacing their DPF with a hollow shell and claiming the extra soot out the exhaust is from a regen on the way to the test centre ;)
 
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Thanks for all your replies. My 10 year old Scudo doesn't have a DPF. These filters do appear to be a problem, but I suppose necessary because of all the people now driving Diesels.

Think I might wait a while before replacing the Scudo, but I inevitably I will end up with a DPF equipped van.

Interesting to see that VAG engines run at a min of 3000 rpm. I would have thouht this a bit strange, as surely this increases pollution and reduces MPG.

All getting too complex. Anyone got a Moggy 1000 van for sale?
 
I've had quite a bit to do with these. They became common when the "Euro 5" type approval emissions requirements came into force. The trouble is, different manufacturers fitted them at different times (some doing so ahead of the legislation) so it's hard to give an exact date. Generally anything registered from the start of 2010 is almost certain to have one, and anything registered before 2007, is pretty unlikely to have one. That's only a rough rule of thumb though.

It's certainly true that they need to "regenerate" periodically. Different manufacturers have different strategies but all of them need to get the filter stinking hot for it to work. That's best done with the engine running weak (typically sustained light load conditions) so actually booting them along the motorway might make things worse. You really want to be doing 50-70 on the level, on a light throttle opening. Hard acceleration will actually PRODUCE soot (which is pretty counter-productive during a regen)!

my last 5 company cars have had DPFs - none of them has given me a moment's bother, but I do 25,000 miles a year and much of it is motorway. I certainly wouldn't recommend a diesel to someone who wasn't going to do at least one 20+ mile run per month at relatively constant speed.

They don't just store the soot and then dump it back into the atmosphere. Soot is formed when there's incomplete combustion (really rich mixture). If you get sufficiently little fuel, it burns more completely (which his why diesels (healthy ones at any rate!) don't smoke in normal constant-speed running. The DPF just holds on to the soot and then gets hot enough to completely burn it (so instead of forming particles of visible carbon (soot) the carbon is combined with fuel / air (and one some vehicles, magic chemicals) so that it forms compounds rather than soot particles).

It's illegal to remove a DPF (though plenty of people do!) but DFT and VOSA (or DVSA as they're called today!) are working towards developing MOT test procedures to try an spot that.
 
My 07 Civic doesn't have a DPF (from OEM). Iinm OEM (uk) civics never had them fitted as standard until 9th gen was released,

Honda has solved the "clogged DPF" issue by attaching the DPF to the exhaust manifold where the exhaust gases are naturally hottest (apart from inside the cylinder immediately after detonation !!)

So... Buy a Honda !!

lol

Unless Honda have been granted a worldwide patent on that like their "Magic Seats" I can't see it being long before other manufacturers implement similar ideas.

As for regen.. just drop a cog for 5mins.
 
Avocet said:
I've had quite a bit to do with these. They became common when the "Euro 5" type approval emissions requirements came into force. The trouble is, different manufacturers fitted them at different times (some doing so ahead of the legislation) so it's hard to give an exact date. Generally anything registered from the start of 2010 is almost certain to have one, and anything registered before 2007, is pretty unlikely to have one. That's only a rough rule of thumb though.

It's certainly true that they need to "regenerate" periodically. Different manufacturers have different strategies but all of them need to get the filter stinking hot for it to work. That's best done with the engine running weak (typically sustained light load conditions) so actually booting them along the motorway might make things worse. You really want to be doing 50-70 on the level, on a light throttle opening. Hard acceleration will actually PRODUCE soot (which is pretty counter-productive during a regen)!

my last 5 company cars have had DPFs - none of them has given me a moment's bother, but I do 25,000 miles a year and much of it is motorway. I certainly wouldn't recommend a diesel to someone who wasn't going to do at least one 20+ mile run per month at relatively constant speed.

They don't just store the soot and then dump it back into the atmosphere. Soot is formed when there's incomplete combustion (really rich mixture). If you get sufficiently little fuel, it burns more completely (which his why diesels (healthy ones at any rate!) don't smoke in normal constant-speed running. The DPF just holds on to the soot and then gets hot enough to completely burn it (so instead of forming particles of visible carbon (soot) the carbon is combined with fuel / air (and one some vehicles, magic chemicals) so that it forms compounds rather than soot particles).

It's illegal to remove a DPF (though plenty of people do!) but DFT and VOSA (or DVSA as they're called today!) are working towards developing MOT test procedures to try an spot that.
Click to expand...

Excellent post!
John :)
 
Ta! :D I don't work directly manufacturing mass-produced cars, but we convert a lot of them (wheelchair-access) and they're the worst sort of vehicle to have as a diesel. We regularly see them back from their Motability lease having done 4 or 5000 miles a year. 2 years ago we were about 95% diesel, 5% petrol, now we're nearer 30% petrol. We also sell some as taxis and (despite the near-constant urban use) they rarely seem to have DPF problems.
 
http://www.dieselcarmagazine.co.uk/features/euro-6-understanding-the-new-regulations/

Quote.
...almost all of the Mazda line-up already meet the Euro 6 emissions regulations, with all Mazda3, Mazda6 and CX-5 models already meeting the tougher standards. And Mazda engineers have been extremely clever in achieving them without the need for expensive aftertreatment systems. Thanks to a low compression ratio, the 2.2-litre diesel engine doesn’t require either lean NOx traps or selective catalyst reduction...

...Exhaust Gas Recirculation (EGR) is a key player in reducing NOx emissions, and is based on replacing some of the air in the intake gases with recycled exhaust gas, mostly carbon dioxide. These gases replace some of the nitrogen that comprises 80 per cent of air, thus reducing the amount of nitrogen available to be oxidised to NOx during combustion. Engine conditions that cut NOx emissions tend to increase particulate emissions, and vice-versa, which further adds to the difficulties. NOx reduction at source, without any need for further exhaust processing to reduce NOx, has in some engines been achieved by clever engineering of EGR systems, whilst Mazda has reduced the compression ratio of its new SkyActiv engines (to just 14:1) to reduce combustion temperatures and, along with EGR and variable exhaust valve lift, are meeting Euro 6 limits without any further treatments...

So many different models, versions, engines, attributes etc. No one car seems to embody all the best features... Could be manufacturing is so adept at designing, building and supplying new models to the showroom, they are leaving behind the R&D necessary to ensure a reliable product.

Or do they percieve us, the customer (WTF is that ?) as not caring, just desiring 'bling' ?

-0-
 
My 2010 Peugeot Partner Tepee doesn't have a DPF, but that seems to depend on the engine fitted. Mine's the 1.6.
I'm pretty sure that later ones all do have them fitted.
Petrol next time for me.
 
If you are prepared to run an older car with the Hdi 8 valve engine, these are almost indestructable but were only available in most cars up until 2004. I have a 406 and a C5 both with 200k miles plus and both mostly original including clutch and DMF . They don't have a DPF.

Peter
 
I have found BMW's to be great up until 100k, then problems start, the most reliable DPF'ed cars on our fleet have been Hyundai, probably due to their regen criteria being low, they can regenerate at speeds of 15 mph or greater, I think BMW's & most other German cars need speeds over 40mph to do so.
 
It's not so much road speed that's needed as the right engine conditions. They need a weak mixture and LIGHT load so that they're running weak (and therefore hot) and they mustn't drop down to tickover (or close to it) or there isn't a sufficient flow of hot gas to keep the process going. Most of them will regenerate at a constant 1500 RPM or above and relatively small throttle openings. A constant 50 along an A road (if you can find one where you CAN do a constant speed for 15 minutes or so) ought to be enough. Accelerating hard is where diesels make the most soot - so that's actually counter-productive when it's trying to get rid of the soot during it's regen!
 
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