Diesels and DPF's

  1. cumbriasteve

    cumbriasteve Moderator Staff Member

    Messages:
    9,382
    Location:
    Cumbria UK
    I understand the basic concept of DPF's but would like to know more.

    I know how the regen system works but does the action fully clean the DPF.

    Or is it slowly clogging over time regardless of regens and one day will simply not burn itself clear enough to eliminate dash lights and limp home mode.

    Do the advertised 'clean your DPF for £99' franchises work or does it just clean it enough to work but sooner or later it's big spends time.
     
  2. RonA

    RonA specialist in repairing sealed for life equipment

    Messages:
    980
    Location:
    Stockton on Tees, UK
    from what I've heard eventually you get to a point where the dpf won't regen & you have to get cleaned by one of those firms or buy a replacement.
    RonA
     
  3. cumbriasteve

    cumbriasteve Moderator Staff Member

    Messages:
    9,382
    Location:
    Cumbria UK
    Yeah I sort of suspected that, can't seem to find much feedback on the clean them firms at the moment.

    Not having any trouble with a DPF just future plans make considering the pitfalls worth thinking about.
     
  4. Justme

    Justme Member

    Messages:
    2,594
    Location:
    Pwllheli Wales
    Drive more, longer faster hotter.

    You then wont have issues.

    Its the short trips that kill them.
     
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  5. Justme

    Justme Member

    Messages:
    2,594
    Location:
    Pwllheli Wales
    We have 3 cars with them.
    Two get longer drives one not so often.
    Only one ever gets a message re needing a clean / limp mode & then only if its not had a long trip recently.
     
  6. Ashley Burton

    Ashley Burton Forum Supporter

    Messages:
    1,687
    Location:
    Northamptonhire
    DPF's can be less of a problem if driven regularly on long enough drives to get them upto operating tenperatures.

    Cleaning is required when a DPF is blocked more than its maximum pressure difference.

    EGR Valves & Turbo performance can have an effect on DPF's.

    Also running low on fuel (normally less than a quarter of a tank) can stop vehicles from regenerating.

    In regards to cleaning some of these treatments don't work. People that offer off car cleaning Services normally have more success.

    Hope that helps
     
  7. cumbriasteve

    cumbriasteve Moderator Staff Member

    Messages:
    9,382
    Location:
    Cumbria UK
    Thanks folks, I only do 5 to 7k a year local with the occasional run out and a couple of long runs a year and have never had a problem or seen a dash light in six years of ownership, it's just at the back of my mind I am pushing my luck though.
     
  8. Migmac

    Migmac Member

    Messages:
    2,564
    Location:
    Kintyre. Scotland
    Ours has been fine, it does lots of short journeys but does get a hammering now and again if i’m using it. Did look into getting rid of the dpf and getting the system remapped. Didn’t do anything about it as I quite fancy another car after the winter. Trying to get one car to do us rather than two
     
  9. cumbriasteve

    cumbriasteve Moderator Staff Member

    Messages:
    9,382
    Location:
    Cumbria UK
    I thought that was an instant MOT fail now?

    Am fairly sure I understood it that if the vehicle was supplied from new with a DPF it had be in place regardless if it passed the emission tests.
     
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  10. tom 748 Member

    Messages:
    63
    Location:
    scotland
    removing is a mot fail
     
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  11. Ashley Burton

    Ashley Burton Forum Supporter

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    1,687
    Location:
    Northamptonhire
    I wonder why people remove the internals :whistle:

    If you haven't had a problem in 6 years, Then I wouldn't worry yourself too much
     
  12. aguycalledsteve

    aguycalledsteve Forum Supporter

    Messages:
    253
    Location:
    Mansfield
    Gotta be good at hiding it now too. IIRC any evidence of the DPF being cut and welded will result in a fail.
     
  13. Migmac

    Migmac Member

    Messages:
    2,564
    Location:
    Kintyre. Scotland
    It is a fail, but if the Mot garage can’t see it due to under body guards maybe it would pass, espicially if the car has been remapped in some way
     
  14. Migmac

    Migmac Member

    Messages:
    2,564
    Location:
    Kintyre. Scotland
    Think it was the sinspeed web page I looked at
     
  15. pondy

    pondy Member

    Messages:
    1,201
    Location:
    chedburgh, suffolk. uk
    Overtime the efficiency of the dpf with go down hill with every regeneration it does. Every time it burns the particulate matter off it then creates a layer of Ash which over time fills the filter. Cleaning companies offer a service to clean the Ash etc out or you can be naughty and stick a pressure washer through the reverse end of it
     
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  16. Ashley Burton

    Ashley Burton Forum Supporter

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    1,687
    Location:
    Northamptonhire
    Had one on a sprinter where someone had run a drill through. Not even had to cut or weld it
     
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  17. doubleboost

    doubleboost Forum Supporter

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    2,237
    Location:
    North Easr England
     
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  18. reb78 Member

    Messages:
    315
    Herts UK
    Diesels really the wrong engine for this sort of driving IMO. Better off getting a petrol next time. On short journeys, a diesels economy isnt significantly better than a petrol, its on the long journeys they pay off and then the DPF can get hot and regen as it should.
     
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  19. carbon

    carbon Member

    Messages:
    832
    Location:
    S. Glos. U.K
    I have a vw T5 with dpf and never had the dash light on but system does regen fairly regularly usually after a reasonable trip on the motorway. Can usually tell with that as lots of heat when outside and smells like a wood fire from inside also doesn’t drive the same in traffic as usual, slightly lower rpm’s and hesitates a little when accelerating
     
  20. anto44

    anto44 Member

    Messages:
    829
    Location:
    ireland
    The dpf is basically a filter that catches the soot produced by the engine, when the filter starts to get full the ecu will watch for a set of conditions to be met to start a regeneration process. These conditions are coolant, oil, exaust temps etc. All the conditions have to be met to start a regeneration, these include vehicle speed and throttle position (having cruise control on increases chances of a regeneration) and these are the 2 that cause the most problems with cars used for short stop/start joirneys.
    DPFs are actually incredibly reliable units, a huge number of failures are actually miss-diagnosis, there's a lot of mechanics out there who don't understand how they work. A common one I see is DPFs diagnosed as gone when it's actually a pressure sensor thats gone and people go remove the DPF because they've been quoted over 2k to fix when actually a 60 quid sensor was all it needed.
    The fact you're only doing 5 to 7k a year isn't something I'd be concerned about, it's more the type of driving conditions it will be used in for that 5 to 7k that's what will dictate how well a DPF car will serve your needs.
     
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