Why service your car before its MOT

An MOT and a service are two different things. The MOT is a yearly check that your car meets road safety and environmental standards. A service is maintenance: changing the oil and filters and looking after the parts that wear. Having a service done shortly before the MOT, or doing one yourself, is a sensible way to find small problems before the tester does.

What the MOT does and doesn't cover

The MOT checks items such as the lights, brakes, tyres, steering and suspension, wipers and washers, seatbelts, the exhaust and the car's exhaust emissions. It doesn't cover the condition of the engine, clutch or gearbox, and GOV.UK is clear that an MOT isn't the same as having your car serviced.

So an oil change isn't part of the MOT, and the tester won't ask to see your service history. But the state of the engine still shows up in places the tester does look: the exhaust emissions, the engine warning light and any fluid leaks.

Why a service before the test makes sense

• Emissions are tested. The limits depend on the car's age and fuel type. An engine fault that affects emissions is better found at a service than on the day of the test.
• Warning lights count. On petrol cars first used on or after 1 July 2003 and diesels first used on or after 1 July 2008, an engine management light showing a fault is a major defect. The airbag, ABS, power steering and brake fluid warning lights are checked too. A service is a good time to get any warning light looked into.
• The diesel smoke test needs a healthy engine. The tester won't carry out the smoke test if the engine isn't in a safe condition, for example if there isn't enough oil in it or the camshaft (timing) belt is in poor condition.
• Leaks are checked. A fluid leak bad enough to harm the environment or put other road users at risk is a major defect.
• Wear items get a look. Wipers, bulbs, tyres and brakes are all MOT items, and a service is the natural moment to look at them.

A service won't decide the result on the day, but it gives you the chance to sort the small things before the test.

Oil and filters

Change the engine oil and oil filter, using the oil grade and specification given in your handbook. Check the air filter and the cabin (pollen) filter, and replace them if they're due or dirty. Your car's service schedule tells you how often each part should be changed, along with items such as spark plugs, the fuel filter and the brake fluid.

Wipers, bulbs and fluids

• Wiper blades: replace them if they smear, judder or the rubber is split. The wipers must clear the screen properly to pass. See our wiper blades.
• Screenwash: fill it up. The washers must provide enough fluid for the wipers to clear the windscreen. See our screenwash.
• Bulbs: walk round the car with each light switched on and replace any that have blown. DVSA's MOT figures show lamps, reflectors and electrical equipment are the most common category of MOT defect. See our car bulbs.
• Coolant and brake fluid: check the levels against the marks on the reservoirs. Low brake fluid should always be investigated, as the Highway Code warns it may result in brake failure.
• Battery: check it's held down securely and the terminals are clean and tight. The MOT checks that the battery is secure and not leaking.

Tyres and brakes

Check that each tyre has at least 1.6mm of tread across the central three-quarters, all the way round, with no cuts or bulges, and set the pressures with the tyres cold. Look at the brake pads and discs through the wheels for thin pads, deep scoring or a raised lip at the edge of the disc, and listen for squealing or grinding when you brake. Pads and discs should always be changed in pairs across an axle.

Doing it yourself

If you service the car at home, our service kits group the filters for your car together, matched to your registration, with oil sold separately. Check every part against your car before you start, keep the old parts until the job is done so you can compare them, and write down the date and mileage so you know when the next service is due.

If you'd rather leave it to a garage, booking the service a week or two before the MOT gives you time to sort anything they find.

Find engine oil, oil filters, air filters and pollen filters, or browse all service parts for your car, and add it to My Garage to check its MOT history and sign up for an MOT reminder email.