Top Reasons Your Car Might Fail its MOT This Winter

With winter now fully upon us, we’ve teamed up with our headline partners, MOTORS to find out what the most common failures are on an MOT in winter.

While some cars will pass without any issues, for others it’s a different story with MOT fails often resulting in drivers forking out hundreds of pounds in repair costs. To help you look after your vehicles during the worst of the weather conditions, MOTORS have taken a deep dive into Department for Transport data to unearth the most common reasons cars fail winter MOTs.

MOTORS in-depth analysis of more than 20.2 million car MOT tests across winter 2020 and winter 2021, reveals that:

• On average there are 2 million failed MOT tests each winter
• 1 in 5 (20%) vehicles fail their MOT during the winter months
• Tyre tread depth is the most common reason cars fail their MOT 

The most common reasons you car might fail its MOT in winter

MOTORS research reveals that while it’s important to remember a vehicle can fail an MOT for multiple reasons, it’s clear that your tyres, brakes and suspension should be carefully looked after if you want to avoid issues in your next test.

The cost of failed MOTs

Having crunched the numbers MOTORS found there were a total of 20.2 million winter MOT tests across 2020 and 2021, with 1 in 5 (20%) vehicles failing their annual car safety test.

With an average of 2 million failed MOTs each winter, and the most recent research putting the average cost of a failed test at £326.85, Brits will fork out a staggering £653.7 million for failed tests this winter.

To help shine a light on the areas of a car that drivers should prioritise looking after, and help you try and avoid an unwelcome winter bill, we’ve teamed up with MOTORS to share some top tips on how to avoid just a few of the most common MOT failures.

Tyre Tread Depth

The most common reason cars fail an MOT is because of a lack of tread depth – accounting for 36.47% of failures. Good tyre depth is essential for maintaining grip on the road and allowing your car to brake successfully. A lack of tyre tread depth increases your chances of having an accident, especially in the wintertime when icy or wet roads already make braking more difficult. 

The minimum legal requirement for tread depth in the UK is 1.6 millimetres, although we advise you to replace your tyres well before, at 3 millimetres; any less and your stopping distance when braking will start to increase. Testing your car’s tread depth is imperative not least if you’ve bought a used car. To do this, take a 20p coin and run it along the tread groove. If the outer band of the coin disappears you’re good to go, but if you can still see the outer band, it’s time to replace your tyres. 

On top of keeping an eye on tread depth, you must also ensure your tyres are correctly inflated and that you limit heavy braking, acceleration and sharp steering.

Tyre Faults

Several different issues fell under tyre faults, the second highest reason for MOT failures. Among them were seriously damaged tyres, visible or damaged tyre cords, a tyre not being fitted correctly and a tyre fouling another part of the vehicle. 

Taking care of your tyres is pretty straightforward though. It is recommended that you change them every 20,000 miles or every 10 years (whichever comes first), and you should regularly check them for visible damage. Look out for cracks or cords which are a telltale sign you need to replace your tyre. 

Brake discs and pads

The third and fourth most common reasons were brake discs and pads. These essential components are vital to your car’s braking system and having issues with either or both could significantly affect your ability to stop. 

In the winter, colder temperatures and excessive braking can overwhelm your braking system. To help reduce the risk of issues with your discs and pads we suggest keeping your car in a sheltered area, such as a garage if you have one. Try not to ‘ride on the brakes’ i.e. keeping your foot on the brake for long periods of time. Instead, select a higher gear to control speed and utilise your hand brake and engine braking when coming to a stop.

Coil Springs

As part of your vehicle’s suspension, coil springs absorb the impact from potholes, bumps and rough terrain. The cold weather in winter can affect the steel in the springs making them brittle and more likely to break when impacted by harder, tougher and gritted roads. It’s therefore unsurprising to see them contribute to more than 1 in 7 (16.4%) cars failing their MOT across the winter months. 

To help minimise damage to your coil springs, try to avoid potholes where possible and ensure you wash under your car to remove salt from gritted roads which can erode the springs.

For more tips on everything from buying your next car, to driving tips and info on the latest car tech and EV’s make sure you head over MOTORS Advice Hub for more expert advice and insights.