Stricter MOT tests for diesels

From 20 May, MOT test are changing and diesel vehicles will receive a major fault if there is evidence that the diesel particulate filter has been tampered with or if coloured smoke comes from the exhaust

Rather than simply passing or failing an MoT, from 20 May new MOT tests will categorise defects as either ‘minor’, ‘major’ and ’dangerous’, depending on the type of problem and how serious it is. Major and dangerous faults will result in an automatic fail.

‘Advisories’ can also be given out, which will be items that the driver will need to monitor.

The new MOT test includes the introduction of stricter checkes for cars with a diesel particulate filter (DPF), which captures and stores exhaust soot to reduce particulate emissions from diesel cars.

Previously the MOT only required a visual inspection of the DPF. But the new rules will require a much greater assessment. If smoke of any colour is seen coming from the exhaust, this will mean the vehicle will be given a ‘major’ fault and will fail the test.

If there is evidence to suggest that the diesel particulate filer (DPF) has been tampered with, the vehicle will also fail the MOT.

The new test requirements are the result of an EU directive imposing better emissions testing and stricter vehicle checks.

Why are DPFs so important?

Diesels produce particulate matter that can cause respiratory problems. In fact, it is estimated that 40,000 people die early because of health issues that arise from bad air quality – with diesel vehicle emissions being a significant cause of the pollutants.

Since 2009, modern diesel cars have to be fitted with a Diesel Particulate Filter to prevent soot passing into the environment.

The filters have to be ‘emptied’ to keep them in good working order, and this typically happens by itself when the car reaches high speeds for prolonged periods of time, when the exhaust temperature is high enough. The collected soot is burnt off in a process known as ‘regeneration’.

Many cars also have ’active regeneration’ which is triggered when the vehicle can not achieve regeneration by itself because high speeds are not achieved. This is when engine control software senses if the filter is getting blocked and injects extra fuel into the engine to raise the exhaust temperature to trigger regeneration.

A warning light will come up if the filter is blocked, but it can normally be remedied if the vehicle is driven for 10 minutes at speeds over 40mph.
Under the Road Vehicles (Construction and Use) Regulations, using a vehicle which has had its DPF removed is an offence and can incur a fine of up to £1,000 for a car or £2,500 for a light goods vehicle.

According to the DVSA, around 1,800 drivers have been found to be using a vehicle without a DPF since 2014.
Frank Kelly, professor of environmental health at Kings College, London, commented on the detrimental health impact caused by diesel vehicles not having a DPF.

He told the BBC: ”If a DPF is removed, it takes the work being done to restrict emissions back 30 years.

“A car with a DPF removed has a particulate count 20 times higher than one with it.”

Other changes to MOT

Additional items will be checked during the new-style MOT. Tyres will be looked at to check if they are obviously underinflated, brake fluid will be looked at to make sure it hasn’t been contaminated, and fluid leaks will be assessed to see if they pose an environmental risk.

What’s more, brakes will be checked to see if there are pads or discs missing and the warning lights will be examined.

Daytime running lights will be checked on vehicles first used from 1 March 2018.

Reversing lights and headlight washers will also be checked.

The design of the MOT certificate will change, so that defects are listed under the new categories.

Drivers with vehicles with defects deemed to be dangerous that continue to drive their vehicles will risk a £2,500 fine and penalty points on their licence.

Vehicles over 40 years old
Cars, vans, motorcycles and other light passenger vehicles will not need to have an MOT if they’re over 40 years old and have not been substantially changed.

At the moment, only vehicles first built before 1960 are exempt from needing an MOT. When the rules change on 20 May 2018, vehicles won’t need an MOT from the 40th anniversary of when they were registered. Drivers can check the date their vehicle was registered online at the gov.uk website.

The first MOT

In January this year, the government decided not to increase the period before a car’s first MOT to four years – keeping it to three years due to safety concerns.

The Department for Transport put out a consultation on the matter. Reasons for the possible change included the money it could save drivers, and also the fact that vehicles are a lot safer than when they were when the MOT was first introduced in 1960.

Most of those that responded to the consultation on the matter were against the proposals on safety grounds, arguing that the savings to motorists were outweighed by the risk to road users and the test often highlights upcoming issues affecting the vehicle. A public survey for DfT by Populus also showed fewer than half of people were in favour of the change.

The MOT test originally only required vehicles to undergo a first check after 10 years. It was changed in 1967 to three years.