MoT changes on DPFs from this month

Posted on February 21st, 2014 by Rob Marshall

dpfUnderstandably, with so many motorists desiring enhanced fuel economy, reliability and performance, hundreds of businesses around the UK have sprung up that remove diesel particulate filters (DPF), which are located within the exhaust system. The downside is that the levels of toxic exhaust emissions will increase but many owners see this as a ‘price’ worth paying, especially as those people outside of the vehicle are the ones that bear the social cost of breathing in poorer quality air. This is proven, to some extent, by the problems that the City of London is facing, complying with clean air emissions standards, especially in relation to particulates and nitrogen dioxide, both of which are emitted primarily by diesel-powered road transport.

However, most cars that are equipped with DPFs could not have been sold in the UK, when new, without them. While removing particulate filters has always contravened Regulation 61A of the Road Vehicles (Construction and Use) Regulations 1986 and European Directive 2010/48/EU, the lack of awareness and enforcement has allowed DPF removal to flourish. One of the reasons is that the MoT Test’s diesel emissions test is so basic, that a modern car does not need a DPF to pass it. This has fooled many car owners and DPF removal companies into thinking that the modification is legal.

Yet, from this month, a new rule comes into force at MoT Test time, which is intended to fail cars that have received the modification. Unfortunately, because an MoT Tester is not permitted to dismantle anything, the test can only be a visual check. Therefore, despite the government’s good intentions, it is feasible to cheat the ruling, by an unscrupulous individual removing the exhaust system, smashing out the DPF’s core and refitting the original empty casing. From beneath the car, the MoT Tester would never know that the work had been done and, therefore, would award the car with a pass

Should this tempt you to have the procedure done to your car, my advice is, don’t do it. Although the recent MoT Test implementation can be thwarted, you are breaking the 1988 Road Traffic Act, which states that a vehicle should not be modified in a way that would make it unroadworthy. Yet, checks for a filter’s presence are not impossible and you could still be found out. An inspection, carried out either through the car’s diagnostic computer, or by using a camera probe, inserted into the DPF canister, are possible ways for an insurance assessor to tell. We have heard of some insurance companies stating that they would refuse a claim and one even refused to issue a quotation, were a DPF removal declared before the MoT Test change.

If your car is suffering from DPF problems, you can make savings. The first option is to replace the DPF with one sourced from an aftermarket supplier and these parts have to satisfy the same performance and longevity tests as the dealer-supplied part. Opting for this route could save you up to 70% on the parts costs. The alternative is to have your original DPF cleaned chemically and several businesses have established a nationwide mail-order cleaning service. Yet, if you find that your motoring consists of mainly short stop-start journeys, a modern diesel will be unsuitable for your needs and you ought to consider a trade-in for a petrol model instead.