Removing the removers

Phil Curry looks at the problem of DPF removal

Published:  03 June, 2016

A car cannot pass its MOT without a DPF in place, should it have left the factory with one. This statement is true and has been true since February 2014, yet the MOT is still only a visual check with no parts allowed to be removed for inspection, a loophole that is constantly being exploited by DPF removal companies.

A quick search online and people are talking about DPF removal on forums while websites are still offering the service. One website even asks the question ‘will my car fail the MOT’ and answers with: “From February 2014 the law is changing to include the visual inspection of the diesel particulate filter during inspection. We do not replace the DPF with a straight pipe (which is a fail). We leave the DPF housing intact and remove the internals, not affecting the visual inspection on an MOT test...”<

The website fails to mention that not having a DPF on the car is an MOT failure and if it were to be found that the innards had been removed it could prove costly for the driver. Other sites quote their work to be ‘MOT Friendly’ without informing the customer of the consequences.


According to the DVSA, since the rule came into the MOT in February 2014, around 1,000 cars have been caught without a DPF. It is however estimated that the number on the road is considerably higher due to the fact that removing them is not an illegal practice. With a simple visual check only part of the MOT, the practice of ‘gutting’ means that many cars without the DPF are missed. It is akin to banning bringing certain products from France to the UK via ferry but not ruling out the Eurostar, what would be the point? There needs to be a blanket ban or at least a way of discovering the lack of a filter during the MOT another way.

The DPF is installed for a reason, mainly to help vehicles achieve Euro 5 emissions regulations. However, with a large number of drivers buying diesel vehicles for their good fuel consumption figures and not due to the need to drive long distances, the particulate filter does not get to the required temperature to regenerate, meaning after a period of time it will become clogged and potentially damaged. Alternatives, such as a clean or flush by a garage are not taken into account as some drivers are not aware of the necessity of this treatment. Therefore, the DPF is seen as a burden, which affects vehicle power, performance and reliability, so the long term solution is to remove it.


The main way DPF removers get their business is by targeting motorists through online advertising. As mentioned before, Google listings still feature companies offering the service and some are even hosted under the search provider’s AdWords program. There have also been instances of DPF removal firms using popular websites such as eBay to target motorists.

This has prompted environmental campaign group Friends of the Earth to lodge a complaint to the Advertising Standards Authority. The group points out that the advertising code of practice sets out principles stating that marketing communications should be “legal, decent, honest and truthful”.

It goes on to state that adverts on the removal of diesel particulate filter’ devices from diesel cars are in breach of section 3.3 of the code, which says “marketing communications must not mislead the consumer by omitting material information” – the material information in this case being that your car will be illegal once the procedure has been carried out – and section 4.4 of the code, which states “marketing communications must contain nothing that is likely to condone or encourage violence or anti-social behaviour”. These ‘DPF removal’ adverts, in failing to mention that the service they offer leaves consumers with a law-breaking vehicle, are clearly in breach of this standard.

Friends of the Earth air pollution campaigner, Oliver Hayes comments: “Air pollution is a public health crisis of breath-taking proportions. The dodgy practice of removing pollution filters from cars is not only risking people’s health, but also putting drivers at risk of prosecution for the simple fact that it’s illegal to drive a car with its DPF removed.

“We’re asking the ASA to clamp down on those advertising these dubious practices and help prevent more deadly pollution hitting our children’s lungs. But we’re also calling on the government to make it illegal to remove these pollution filters in the first place. Unless they do, the absurd loophole remains whereby unscrupulous garages can remove a pollution filter but it’s only the driver, once they’ve turned the engine on, who is breaking the law.

Tougher checks 

Another way to clamp down on DPF removal is to make it harder for the driver to get away with it, while also ensuring that any vehicle breaking the law is taken off the road and remedied. This is a view held by Cameron Bryce, Managing Director of DPF Clean Team, who comments: “Anyone who is advocating the illegal removal of DPFs, catalytic converters and silencer units is not only breaking the law but is misleading motorists too. It may seem a cheap and quick option, but it is costing them money in the long run. Not only is it invalidating their insurance, but it often damages other parts of the vehicle too. Removal of these components does not address some of the wider issues that have caused blockage, such as a faulty temperature or pressure sensor, faulty glow plugs or a failed exhaust gas recirculation (EGR) valve.”

In a bid to combat what some see as a failure to detect missing DPFs, the Department for Transport has commissioned research to better detect their removal by measuring the exhaust fumes of a diesel vehicle, with their findings contributing to changes set to be made to the Roadworthiness Act which are scheduled for 2017/18. Industry bodies already believe the answer is to make the emissions test at the MOT apply to diesel vehicles with a more sensitive setting to flush out those without the filter fitted.

Bryce continues: “While it’s good to see the government taking action against DPF removal, what we really need to see is the return of spot checks on the road, greater enforcement and a better system for MOT checks, rather than basic visual inspection. Motorists everywhere need to know there are options such as professional cleaning and aftermarket replacements, which are not only far more cost effective and legal, but can treat all the other issues surrounding DPF blockage that removal often fails to address.”

The solution? 

Speaking to the Guardian newspaper, Roads Minister, Andrew Jones, said: “We are fully committed to improving air quality and the new figures are proof that our common-sense changes to the MOT test are helping get hundreds of polluting vehicles off the road. We continue to tackle harmful vehicle emissions and are investigating ways to use the latest technology to further improve detection methods.”

Two very different paths are being presented here, should drivers be punished for having no DPF, or should the firms that remove them be stopped? Is deterrent a good solution to the problem or should it be cut off at the source?

Police in Spain have already begun clamping down on removal firms, with raids taking place in October 2015 on eight garages offering the service. Meanwhile, firms in the US have been fined for advertising DPF removal. With the rest of the world taking the remover out of the equation, it should be time for the UK government to do likewise.

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