The Most Common MOT Fails

The Most Common MOT Fails

Car MOT fails - Mechanic

Owning a car can be an expensive business, from fuel to tax and insurance it can sometimes feel like the amount of money required to keep your car on the road is ridiculous. However once we get used to the regular payments and keeping up with the finances needed it becomes easier, although in the case of MOT’s this financial security can come crumbling down. 

Anyone who has owned an older car will know the fear. MOT coming up and having that nagging feeling that something severe is hiding under the bonnet, just waiting to be found. Once the problem is identified, who knows how much it would cost to fix? Well luckily there isn’t too much precedent for this, after all if your car were on its last legs you would certainly notice it when driving in most cases!

That doesn’t mean that your car will pass it’s MOT though, and many vehicles have failed over the years on the most innocuous of things. Once failed then not only will this be marked on your vehicle’s record permanently, you’ll also need to shell out more money and find more time to book your car in to fix and re-test the vehicle. 

In this article we will cover the most common MOT fails and how you can avoid them before you book in your next test. If you’re already confident your car is ready, then you can get in touch with your garage sooner rather than later. If you’re based in Kent then an MOT in Tunbridge Wells is likely your best option.


Representing as much as 30% of all MOT fails, not being aware that your bulbs aren’t working is common. The annoying part of this type of MOT failure is that it’s so easy to notice and change prior to testing. 

Many cars will let you know when a bulb has gone out, but get someone to help you by running all the lights on your car while you walk around checking them. It’s also worth giving them a tap to ensure that they are secure in their housing. 

Happily if you do have any issues in most cases they are easy to fix yourself. You may require assistance for certain models as the bumper can need to be removed to access areas like the headlights.


Representing around 10% of total failures, tyres are easy to forget about especially in the summer months. Your contact with the road is all through your tyres so having the correct tread and suitable tyre condition is vital. 

More than anything else an issue with a tyre can result in a serious accident, or at best being stuck by the side of the road waiting for rescue. As part of your MOT the mechanic will review the tread depth and general condition of all four tyres. Issues can include worn treads, damaged sidewall and debris such as nails being present. 

Checking your tyres is simple, the famous 20p test will help give a good indication of your tyre depth. The 20p coin should sit nicely in your treads at all points of the tyre, with the inner ring hidden inside. If your coin is sat atop the tread with little obscuredness then your tyres need to be replaced or you will instantly fail your MOT. 

Mirrors, Windows & Wipers

Driver visibility is imperative, and often is an element of the MOT that most owners misunderstand. The MOT test is not just about the driver and occupants safety, but also the safety of other road users. Failing to have the correct level of visibility in day, night, dry or wet is all considered a failure. 

It’s been known for cars to fail simply because of an overly large air freshener hanging from the rear view mirror. The tester will only review the car as is so will not make any adjustments from the condition you dropped off the car in, it may seem petty but a pedestrian in the self created blind spot could be disastrous.

If a rear view mirror is fitted then it must be user adjustable, and the windscreen also free of cracks or chips that would also impede vision of the road. 


Issues with your suspension are not always clear. If you regularly travel on damaged roads full of potholes then you can run the risk of damaging elements such as shock absorbers, especially in vehicles with an extended life span. 

Early warning signs can include lurching around excessively and knocking sounds while driving under normal conditions.

What’s not checked on an MOT?

It’s a common myth that an MOT is the only check you require to ensure your car is working order. An MOT is entirely based on safety, both to yourself, other drivers and users of the road. Anything outside of this is not checked by your mechanic, which is why regular servicing is so essential. 

Elements not checked in an MOT include:

  • Engine
  • Gearbox 
  • Clutch
  • Filters

It’s recommended to try to plan your service just before your MOT if possible. A reputable mechanic will point out any potential failures upon completing the service, giving you time to resolve the issues before booking your MOT.