Nearly 750,000 cars failed their MOT due to emissions defects in the six months following revisions to MOT rules in May 2018. This trend suggests the failure rate is set to reach 1.5 million for the full year doubling the amount of emissions related failures.

The recent changes to the MOT are the most comprehensive changes to the test targeting air quality. Industry experts at Glass’s expect these changes to take more diesel cars and vans beyond economical repair. Jonathan Brown, celebrating 30 years as a Car Editor at Glass’s said, “The latest revision in MOT rules is not the biggest change since the MOT began back in 1960 when the test only affected cars over 10 years of age. However, these changes that aim to improve air quality, will impact older diesels significantly with failure rates likely to increase.”

Specifically, the following changes are having an effect:

• Stricter limits for emissions from diesel cars fitted with diesel particulate filters (DPF)
• Evidence that a DPF has been tampered with will result in a failure
• If smoke of any colour can be seen coming from the exhaust of a car fitted with a DPF, it will fail

Under the new legislation, owners can drive vehicles away from MOT stations that have a major defect as long as the MOT is still valid and the car is roadworthy. This is on the proviso of carrying out repairs immediately. However, owners cannot drive cars with dangerous faults until the problem is fixed. Examples of dangerous faults include missing brake discs, dangerous wheels or leaking hydraulic fluid that affects brake functionality.

Today, diesel vans are four and a half times more likely to fail the new emission element of the MOT. With demand for local deliveries increasing with the rise of internet shopping, there are self-employed drivers with older, higher mileage diesel vans suffering from a lack of maintenance, either due to time or budget constraints. These vans will become the MOT failures of tomorrow.

The MOT changes are having a noticeable impact on dealer buying habits. A vehicle offered at auction, with a long MOT compared to a similar model with little or no MOT affects price considerably, especially as the vehicle age increases.  With ever-tighter regulations, these effects will continue to have negative influence on values on these older vehicles.