Independents react to suggestion on new methods of MOT DPF detection

GW readers speak out on gov's suggestion that it may introduce new methods of testing DPF removal

Independents react to suggestion on new methods of MOT DPF detection

The Department for Transport (DfT) last week confirmed to GW that it is developing “alternative methods of detecting the presence of particulate filters” for possible use in the MOT.

The ongoing research could see new methods of testing diesel particulate filter (DPF) removal introduced as early as May 2017 when changes to the MOT are to be made as part of a revised Roadworthiness Directive.

The confirmation prompted a mixed reaction among independent garages, with many putting the effectiveness of DPF technology into question.

Commenting on GW, Aled said: “In my opinion DPFs are parts designed to appease politicians, they’re not designed to truly achieve the policy maker’s objectives.

“It’s more a case of let’s be seen to be green rather than actually being green.

“Where do DPF’s mostly regenerate?

‘Hypocritical’

“When exhaust temps are up which is typically on A roads, B roads or motorways which means they’re regenerating in the countryside.

“They’re stopping pollution in the cities and dumping it in the countryside, to me that’s just hypocritical.”

A number of garages showed an understanding for motorists facing large DPF replacement bills and the additional costs for associated vehicle faults.

John said: “I understand why they are doing these tests but when a replacement DPF costs £2000 plus, can you really fault people for removing them?

“If the cost of the filter was £100-£300 a time then less people would have them removed and the government would not have this problem.”

For many motorists DPF deletion seems a logical solution, as Simon explains: “We remove and delete the DPF for customers when they come to us after spending in some cases over £1000 on fixing and replacing.

“We are not going to die because a very, very small percentage of DPF’s have been and will be removed”

Support for new methods

Others showed support for new methods of detecting DPF removal, agreeing with concerns that the current visual check is inadequate.

Stuart Duff said: “A welded DPF doesn’t necessarily mean the core has been removed and that’s problem with a visual check.

“Current welding practices can make an almost seamless and perfect weld.

“So some improved inspection, testing clarification is required.”

The law

It is an offence, under the Road Vehicles Regulations, to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet.

Potential penalties are £1,000 for a car and £2,500 for a van.

The DfT told GW: “The legislation makes the owner or user of the vehicle primarily responsible for its condition.

“Whether the person who had removed the DPF, or had offered to remove it, had also committed an offence would be a matter for the courts to decide.”

Have your say in the debate. Do you support calls for a DPF removal crackdown? How many cars have you failed during a test due to removal? Share your experiences and any concerns in the comments below.

18 Comments

  1. I refer to this comment, “When exhaust temps are up which is typically on A roads, B roads or motorways which means they’re regenerating in the countryside.”
    This is typical of the mis-understanding of how a DPF actually works, it’s a common misconception that they collect soot and dispense it while regenerating, when actually what happens is it’s burned and transformed during a catalytic effect into CO2 and H2O. The residue of regeneration namely ash stays within the dpf itself.
    If all Garage’s understood the prociples they may be more inclined to rectify the cause of a blocked dpf and keep the vehicle legal rather than take the “easy” option of removal.

    “They’re stopping pollution in the cities and dumping it in the countryside, to me that’s just hypocritical.”

    Reply
    • Well said Gary, training and equipment to diagnose and repair rather than dispose. What these people do not mention is the knock on effect when a car is sold on to another consumer unaware a vital component has been removed. When the vehicle starts to develop issues (as they always seem to forget about the OXY cat after removing the EGR and DPF) unless the original tuner can be found to reverse the software, the control unit requires replacing along with the DPF, In my mind removing the DPF effectively renders the car fit for scrap, whereas repaired correctly will continue to run perfectly well.

      Reply
      • I couldn’t agree more with this!

        While I have and do offer a DPF delete this is purely for the modified (off road use) performance aspect.

        I do not recommend the removal of a DPF due to failure! And the amount of inquires I get about it it unreal!

        I’ve had to replace very few DPFs due to failure but in every case there has been another component at fault! And now the systems are becoming more complex with atomisers.

        Independents need more guidance on this, and I think there should also be penalties for companies that remove them.

        Reply
  2. I refer to this comment, “When exhaust temps are up which is typically on A roads, B roads or motorways which means they’re regenerating in the countryside.”
    This is typical of the mis-understanding of how a DPF actually works, it’s a common misconception that they collect soot and dispense it while regenerating, when actually what happens is it’s burned and transformed during a catalytic effect into CO2 and H2O. The residue of regeneration namely ash stays within the dpf itself.
    If all Garage’s understood the prociples they may be more inclined to rectify the cause of a blocked dpf and keep the vehicle legal rather than take the “easy” option of removal.

    “They’re stopping pollution in the cities and dumping it in the countryside, to me that’s just hypocritical.”

    Reply
    • Well said Gary, training and equipment to diagnose and repair rather than dispose. What these people do not mention is the knock on effect when a car is sold on to another consumer unaware a vital component has been removed. When the vehicle starts to develop issues (as they always seem to forget about the OXY cat after removing the EGR and DPF) unless the original tuner can be found to reverse the software, the control unit requires replacing along with the DPF, In my mind removing the DPF effectively renders the car fit for scrap, whereas repaired correctly will continue to run perfectly well.

      Reply
      • I couldn’t agree more with this!

        While I have and do offer a DPF delete this is purely for the modified (off road use) performance aspect.

        I do not recommend the removal of a DPF due to failure! And the amount of inquires I get about it it unreal!

        I’ve had to replace very few DPFs due to failure but in every case there has been another component at fault! And now the systems are becoming more complex with atomisers.

        Independents need more guidance on this, and I think there should also be penalties for companies that remove them.

        Reply
  3. I would like to know if a car has had DPF removed , what the complications in the vehicle running?

    Reply
  4. I would like to know if a car has had DPF removed , what the complications in the vehicle running?

    Reply
  5. If the right questions are asked when selling a vehicle and the customer understands about the driving and regeneration of the DPF then there should be no problems with the DPF we have replaced a few DPF’s all because the DPF was not explained to the customer. It is bafoonery to remove them and whoever does should be penalised.

    Reply
  6. If the right questions are asked when selling a vehicle and the customer understands about the driving and regeneration of the DPF then there should be no problems with the DPF we have replaced a few DPF’s all because the DPF was not explained to the customer. It is bafoonery to remove them and whoever does should be penalised.

    Reply
  7. Hi,my reasons for being against not just DPF’s but EGR valves too is the damage they do to engines by in the case of DPF’s causing so much restriction in exhaust flow so as to hinder both fuel economy and power,dilution of the engine oil and premature turbo failure due to excess diesel being injected during regeneration cycles.I see so any turbo’s failing at little over 100k and DPFs due to this . EGR’s almost completely block inlet tracts and cause swirl valves failure due to the abrasive nature of the carbon and massively reduce performance and fuel economy thereby negating the supposed advantage they have.I have been in the slightly unusual position of knowing cars that were remapped and had DPF’S removed and EGR’S blanked at very low mileage and are running like new at 170k plus with no wear in swirl valves etc and are making as much power as when first remapped .We were all hoodwinked into buying diesels to a degree in the first place by successive governments but in reality there are easy ways to reduce emissions if they really wanted to promote to.Things like HHO injection ,if developed correctly would help far more than the stupid DPF’S and EGR valves etc especially when you realise that the soot given out during regeneration is much finer and more carcinogenic than regular diesel soot.

    Reply
    • I too can back up what you say Peter, I too have been in the same position and can confirm that this is the case. Done correctly it can make such a difference. My own car is on 203,000 miles producing 395bhp and is as clean as a whistle.

      Reply
  8. Hi,my reasons for being against not just DPF’s but EGR valves too is the damage they do to engines by in the case of DPF’s causing so much restriction in exhaust flow so as to hinder both fuel economy and power,dilution of the engine oil and premature turbo failure due to excess diesel being injected during regeneration cycles.I see so any turbo’s failing at little over 100k and DPFs due to this . EGR’s almost completely block inlet tracts and cause swirl valves failure due to the abrasive nature of the carbon and massively reduce performance and fuel economy thereby negating the supposed advantage they have.I have been in the slightly unusual position of knowing cars that were remapped and had DPF’S removed and EGR’S blanked at very low mileage and are running like new at 170k plus with no wear in swirl valves etc and are making as much power as when first remapped .We were all hoodwinked into buying diesels to a degree in the first place by successive governments but in reality there are easy ways to reduce emissions if they really wanted to promote to.Things like HHO injection ,if developed correctly would help far more than the stupid DPF’S and EGR valves etc especially when you realise that the soot given out during regeneration is much finer and more carcinogenic than regular diesel soot.

    Reply
    • I too can back up what you say Peter, I too have been in the same position and can confirm that this is the case. Done correctly it can make such a difference. My own car is on 203,000 miles producing 395bhp and is as clean as a whistle.

      Reply
  9. With new method of engine “Hydrogen Carbon Cleaning” every 15-20.000km, most of the problems with carbon deposits and carbon in exhaust can be solved. Of course, HHO injection is much effective.

    Reply
  10. With new method of engine “Hydrogen Carbon Cleaning” every 15-20.000km, most of the problems with carbon deposits and carbon in exhaust can be solved. Of course, HHO injection is much effective.

    Reply
  11. This is all very well and I can understand both arguments but I’m wondering where the innocent buyer of a car that’s bought a car that’s already had its dpf deleted will stand. After all its illegal and garages not gonna tell us even if they know.

    Reply
  12. This is all very well and I can understand both arguments but I’m wondering where the innocent buyer of a car that’s bought a car that’s already had its dpf deleted will stand. After all its illegal and garages not gonna tell us even if they know.

    Reply

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