Diesel drivers in the UK could face costly repair bills because thousands are driving illegal cars

An investigation in the UK has found that thousands of drivers are illegally driving modified cars without diesel exhaust filters.

Because diesel filters process large amounts of particulate matter from the diesel exhaust, the filters can easily become clogged and likely break.

If you have to replace a broken filter on your vehicle, it can cost up to £1000 (€1,135) so to avoid the cost some drivers have opted to have the filter removed altogether.

The procedure to remove the diesel filter from the vehicle is legal and costs only a few hundred pounds, but driving the modified vehicle is actually illegal. That means that any vehicle found with a modified filter will be subject to a fine of £1,000 for a car or £2,500 for a van.

So far, eighteen hundred diesel cars in the UK have been found by the DVSA (Driver Vehicle Standards Agency) to be on the road without the legally required diesel particulate filters.

Scientists have discovered that pollution produced by the diesel particulate matter in the fumes can be damaging to the heart and lungs as well as unborn children in the womb. These noxious fumes have been linked by the World Health Organisation to 38,000 premature deaths every year around the world.

The diesel exhaust filter works by capturing and trapping soot that is part of the exhaust fumes created by diesel fuel. The filter cannot remove the soot itself so it has to burn the soot into harmless ash by using heat from the engine of the car. This process of heating the soot can only happen at very high temperatures such as prolonged motorway driving.

With many cars now using Stop-start nowadays, it means that urban driving does not allow the engine to heat up for a long period causes a diesel particulate filter to clog up with soot, making it likely to break.

Some garages are cutting a small window into the outside of the filter, removing the internal filter and then welding the window shut. This procedure can give the visual impression that the filter is intact, when in fact, it is not. MOTs currently only require a visual test of the outside of the DPF (Diesel Particulate Filter) to see if the filter is functional. Current emission tests are also unreliable for detecting the presence of the filter.

The DVSA in the UK plans to introduce changes to their emission tests that will improve detection of tampered filters. These tests are not scheduled to be rolled out until May 2018. The Chief Executive of the DVSA, Gareth Llewellyn said:

“Vehicles found to have tampered with or missing DPF filters will fail their MOT... DVSA continues to pursue such offences and will take action against any MOT garages found to be conducting illegal modifications.”

Jonathon Grigg, Professor of Paediatric Respiratory and Environmental Medicine at Queen Mary University of London, said the emissions given off by unfiltered diesel engines are "are not taken seriously enough".

"By removing the DPF you are taking a toxic vehicle and making it even more toxic. When you breathe in diesel emissions a lot of what goes into your lungs is soot.

"Some of that soot will continue to stay in your lungs even after you breathe out multiple times.

"Living in an urban area you only take in a small amount of these particles everyday, but what we are learning is that over the course of a lifetime that these effects accumulate."

long-term risks associated with diesel emissions exposure include increased risk of cardiac and respiratory diseases such as asthma as well as slightly higher chance of getting lung cancer.

Author

Justin Kavanagh
Justin Kavanagh is a recognised leader in automotive intelligence and vehicle data supply to the entire motor industry. He has almost 20 years experience in building systems from the ground up. As the Managing Director of Vehicle Management System, he understands the need and importance of trustworthy and reliable vehicle history and advice to both the trade and the public.
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