How to check your vehicle

Most breakdowns are avoidable. Simple vehicle checks can help you have a safer journey, and save you time and money.

How to check your vehicle

Every year our traffic officers deal with more than 85,000 breakdowns. Over 40 per cent of these are caused by vehicles running out of fuel, poor tyre maintenance, power loss and engine trouble. The following simple checks could have prevented some of these breakdowns. 

Tyre tread 

All tyres are legally required to have a minimum tread depth of 1.6mm. 

To check your tyres: 

  • Place a 20p coin into the main grooves of the tread. If you can’t see the raised outer rim of the coin (with the words “TWENTY PENCE” engraved), then the tyre has sufficient tread depth. 
  • Check at least three different places on each tyre, as one part may be more worn than another. 
  • Also look around each tyre to make sure they don’t have any cuts, bulges or other damage to the tyre walls. 
  • Check all of your tyres, including the spare. 

Driving without the legally required amount of tread can adversely affect your grip, braking distance and steering. If you’re stopped by the police and found with illegal tyres, you could receive a £2,500 fine and 3 penalty points per tyre. 

Tyre pressure 

Before setting off on a long/significant journey, check your tyre pressures are suitable for the load. 

  • Most fuel and service stations have an air machine where you can check and inflate your tyres. 
  • Each vehicle has a different recommended tyre pressure, which may vary depending on the load you’re carrying. You can usually find this on the inside of the driver’s door, petrol cap or in your vehicle manual. 
  • Set the air machine to the recommended tyre pressure. 
  • Unscrew the valve caps on each tyre and firmly attach the air pressure gauge – you should hear a ‘hiss’ as it connects – and the machine will give you a reading. 
  • Most machines will automatically inflate or deflate you tyres until they reach the recommended pressure, when they will give a ‘beep’.  

Driving with under-inflated or over-inflated tyres can adversely affect your braking distance, steering, fuel efficiency and the lifetime of your tyres. 


Before setting out, check your fuel levels and make sure you have enough to get to your destination. 

  • Always keep your tank at least one quarter full to avoid running out of fuel. 
  • Make sure you fill up with fuel before a long journey. 

This will help you avoid breaking down on a busy road or motorway, and potentially putting yourself and others at risk. It will also help to avoid long-term damage and repair costs to your engine, fuel tank, fuel pump and fuel filter. 

You can be issued a Fixed Penalty Notice in some locations if your breakdown was foreseeable, which includes running out of fuel. 


Use your dipstick to check oil regularly and before any long journey, and top up if needed. Take your car back to the garage if you’re topping up more than usual. 

To check your oil level*: 

  • Ensure your engine is switched off for at least five minutes and your vehicle is parked on an even surface. 
  • Open the bonnet and locate your dipstick (refer to your vehicle manual). 
  • Pull the dipstick out all the way and wipe it clean with a paper towel to remove the oil residue. 
  • The dipstick should be marked near the bottom in two places to indicate the minimum and maximum oil levels. 
  • Reinsert the dipstick fully back into the engine, then slowly pull it out all the way again to check the level. 
  • The oil residue on the dipstick should be between the minimum and maximum markings. 
  • If the oil residue is below the minimum marking, you need to top up your oil level. 
  • Refer to your vehicle manual for the recommended grade of oil to purchase.  

Maintaining the correct oil level is essential as the oil lubricates, cleans, cools and protects the moving parts of your engine, preventing your engine from seizing up and breaking down. 

*Some newer vehicles don’t have dipsticks and use dashboard vehicle check systems instead. Refer to your vehicle manual for details. 

Screen wash 

To ensure you have good visibility, always keep your screen wash topped up so you can clear any debris or dirt off your windscreen. 

To top up your screen wash: 

  • Open the bonnet and find your screen wash reservoir – the cap will usually be brightly coloured and feature the screenwash symbol. 
  • You may not be able to see the fluid level, but this reservoir can be filled to the top, so it’s always a good idea to top up using a mixture of wash and screen wash. Please refer to the screen wash mixing instructions on the bottle to get the correct mixture. 

Also check your windscreen wiper blades to ensure they’re not dirty, worn or damaged. 


If your indicators, hazard lights, headlights, fog lights, reverse lights or brake lights aren’t working properly, you’re putting yourself and others at risk. They can be a reason for your vehicle to fail its MoT. 

To check your lights: 

  • Ask a friend to help you, or park your vehicle near a reflective surface eg a window or garage door. 
  • In sequence, turn on your indicators, hazard lights, headlights and fog lights to check they’re working. 
  • Press the brake pedal to check your brake lights, and finally select reverse to ensure your reverse light is working. 

Your lights are not only essential for you, they’re also essential for other drivers to understand how you’re driving and how you intend to manoeuvre.