• April 19, 2024

  • Abby Nuttall

  • Articles

Breaking It Down: The Age Your Car is Most Likely to Fail Its MOT

Regular MOTs and services are essential for any driver to make sure their car meets safety regulations and continues to run as it should. But are drivers running some vehicles into the ground more than others?

At Wessex Fleet, we’ve used data from the DVSA conducted through an FOI request to determine what age your car is most likely to fail its MOT, as well as the brand with the least fails and fuel type that is most likely to pass.

20-Year-Old Cars are Most Likely to Fail Their MOT 

Our data shows that 20-year-old vehicles on UK roads have the highest MOT fail rate averaging 37.36%. This may be a figure you’d expect with a vehicle of this age, but our figures show there are even older vehicles that have a higher pass rate.

In comparison, 50-year-old cars featured in our data have a low MOT fail rate of just 17%.

21-year-old cars were the next most likely to fail their MOT, followed by 19-year-old cars. It seems that around this age drivers may need to consider a new vehicle based on the wear and tear of the vehicle. As you’d expect, it was the one-year-old vehicles that were most likely to pass their MOT.

wessex fleet cars most likely to fail mot

50-Year-Old Cars are Less Likely to Fail Their MOTs than Vehicles 30 Years Younger

When we think of a car failing an MOT, we associate this with an older vehicle that may have been on the road for many years and requires higher levels of maintenance. But is this necessarily the truth?

The older the car doesn’t necessarily mean it’s more likely to fail its MOT, in contrast to what many of us might believe. Whilst younger cars — aged from one to five — tend to have a lesser fail percentage rate, this is also true of some of the oldest vehicles revealed in our data.

For example, cars from 40-50 years of age tend to have a lower percentage fail rate than newer cars, aged around 15-20 years. Whilst both vehicle age ranges are classed as ‘old’, there is a distinct difference between the two.

The older the car, the more likely they are to be classed as vintage. Collectors could keep these vehicles and are likely worked on by those who enjoy keeping these types of classic cars.

Cars that are aged 15-20 years are less likely to be considered classic and have most likely been used for a long period and may well be coming to the end of their life span. This would explain the high MOT failure rate of 20-year-old cars at 37.36%.

Fuel Type Analysis: Which Type of Car Tops the MOT Fail Rate?

To better understand which type of vehicle has the highest MOT failure rate, it’s essential to consider fuel type. With electric and hybrid cars becoming more popular, comparing all fuel options is crucial.

With a failure rate of 30.24%, diesel-fueled cars came out on top, closely followed by petrol cars at 28.19%. Whilst there is very little in terms of percentage between the two fuel types, it’s important to note that diesel cars tend to be preferred by those driving longer distances.

Regular, long journeys are more likely to result in increased wear and tear on the car, which could impact the MOT fail rate. Diesel cars can sometimes require special maintenance compared to petrol cars, which may also have an impact on the results of a vehicle’s MOT.

All-electric and hybrid vehicles have a lower MOT fail rate of 15%. This could be due to the fact there are currently fewer of them on the road and the vehicles that are on theroads are newer in comparison to diesel and petrol options.

Average MOT fails by engine type

Fuel Type



Failure Rate













Hybrid Electric (Clean)




Electric Diesel




BMW Models Had the Lowest Percentage of Failures of Popular Manufacturers

Despite having the fourth most MOT tests taken place last year, BMW has the lowest percentage of MOT fails at 21.67%.

Similarly, brands such as Mercedes have a high pass rate — like BMW — which could be because more drivers are buying new models, which means they are less likely to fail. The average age of all BMWs tested was 12 years old, but with the luxury aesthetic of these two brands, drivers could be more likely to keep their cars in pristine condition.

Businesses Could Be Losing Nearly £4k on Older Fleets

From the evidence above, it’s safe to say that older cars that aren’t classed as vintage could be costing drivers money. This is a factor businesses should think about, especially if they need a fleet of vehicles to run smoothly.

From Wessex’s calculations, if you have a 10-car fleet, you could be losing £3,932 per year on MOTs and repairs based on older cars.

Number of fleet cars

Average money spend on MOT & Repairs in the UK







To work out the costs listed above, we took the average MOT cost in the UK and added the highest repair costs business fleets may have to pay to maintain their vehicles. We then multiplied this number by the average number of fleet cars to work out how much businesses may be spending to repair older vehicles.

Simon Naylor, Director of Wessex Fleet, added: “With costs increasing, it’s not surprising that many drivers keep their cars for longer periods. For many businesses though, losing nearly £4,000 in repair costs, depending on your fleet size, could be damaging their efforts for efficiency and profitability. For those businesses who could be driving older vehicles, it could be worth investing or leasing to avoid the repair costs older business cars could be generating.”

Tips on How to Keep an Older Car

Whether you have a classic vintage vehicle or a car that’s simply been on the road for a while, here are some tips to help you maintain an old car and reduce the risk of failing an MOT:

Take Care of the Battery

If you have a classic or vintage car, you may not use it all the time — it might be stored in a garage or on your drive. When a car hasn’t been used for a long period, the battery can degrade and become flat. Whilst you could jump-start it, this can do more harm than good, resulting in additional wear and tear to the engine and more intricate mechanisms. 

To prevent your battery from becoming flat, you could use a trickle charger to keep it topped up when you’re not driving. If you don’t want to invest in a trickle charger, simply take your car for a drive once a week to keep the battery in good condition.

Maintain Brakes

It goes without saying your brakes are critically important when it comes to driving. Maintaining your brakes not only means you can drive safely, but it also means you’re less likely to be presented with a hefty maintenance bill at your next MOT or service. Having your brakes inspected regularly means you are aware of any wear that may need to be taken care of, for your peace of mind when driving. 

Regular Fluid Checks

Fluids are quite literally the lifeblood of your vehicle. Keeping them topped up means your vehicle can continue to function smoothly.

Make sure you regularly check your engine oil levels by opening the bonnet and removing the dipstick. Wipe it and redip it. When you remove the dipstick a second time, your oil should be between the minimum and maximum marker. This will help you determine whether it needs to be topped up.

Other fluids to check include the coolant reservoir and the windscreen washer.

Keep Up with a Service Schedule

Make sure you stay up to date with services and MOTs. Ensuring that you have your vehicle checked regularly means you will be able to identify and rectify any issues that might have cropped up. It also means you can keep on top of any maintenance issues as soon as possible — instead of leaving them to tackle all at once.

Generally, your car’s manual, as well as warning lights on the dashboard will tell you how often services are required. It’s best to budget for a smaller service once a year, and a larger service to be carried out every 2-3 years to prolong your vehicle’s lifespan. Make sure to keep any important car documentation from MOTs and services, and your V5 logbook, as this can improve the value of the car if you’re looking to sell.

Drive Carefully

This may seem obvious, but driving safely can benefit your car, as well as you and your passengers. Using your vehicle’s controls with an understanding of how they work is essential. For example, smooth steering and gentle braking means less wear on the car. Changing gear smoothly will also help to maintain the essential elements of the vehicle.

Diesel Cars Can Require Engine Cleaning to Improve Their Efficiency

Driving a diesel engine can be a good choice if driving long distances for personal or business use. However, drivers need to keep on top of cleaning the engine or filters to keep the efficiency of a diesel car running as smoothly as possible. There are many diesel system cleaners on offer, but you can also clean around it with a toothbrush or sponge to remove any debris from it.

This is where business leasing comes in. With a range of new cars, vans, and even buses to choose from, businesses can have access to brand-new cars in a way that suits them.

Choose from business contract hire, finance leases and contract purchases for a fixed monthly price, with varying options at the end of the agreement depending on your preferences. Find vehicles and leasing options suited to your business needs as well as fleet management support at Wessex Fleet.


Wessex Fleet sent an FOI to the DVSA to ask for the number of vehicles that failed their MOT test from 1st January 2023 – 31st December 2023, broken down by the make and model of the car, engine type and age of the vehicle.


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