Car Maintenance Tips: A Practical UK Owner Checklist

Most of what keeps a car reliable takes ten minutes a month: oil, coolant, screen wash, tyre pressures and a walk round the lights. The rest is knowing which noises and warning lights mean stop now, and keeping to the service schedule in your handbook rather than a number someone quoted you in a pub. This guide covers the checks worth doing yourself, how to do them properly, and where the line sits between a home job and a garage job.

Why does regular car maintenance matter?

Because almost every expensive repair starts as a cheap one that was ignored. A tyre checked monthly costs nothing; the same tyre run underinflated for six months wears out early and can fail at speed. A stone chip touched in costs a few pounds; the same chip left through a winter of road salt becomes a rust bubble that needs the panel prepping and painting.

The practical benefits stack up:

• Safety, which is the whole point of brakes, tyres and lights.
• Lower running costs, because correct pressures, clean filters and healthy plugs all reduce fuel use.
• Fewer breakdowns, since most roadside call outs come from batteries, tyres and cooling system faults that a check would have caught.
• Resale value, since a stamped service history and straight, tidy bodywork are the two things buyers judge first.
• A cheaper MOT, because tyres, lights, wipers and screen wash are among the most common failure items and all four are things you can check in your own driveway.

What should you check and how often?

A car first registered in the UK needs its first MOT three years from registration, then annually. The MOT is a minimum roadworthiness test on the day, not a service, and passing one tells you nothing about the condition of your oil, cambelt or clutch.

How do you check and change engine oil?

Check the oil with the car on level ground and the engine cold, or at least twenty minutes after it was last run so the oil has drained back into the sump.

• Pull the dipstick out, usually the one with a coloured plastic handle, and wipe it clean with a lint free cloth.
• Push it fully back in, then pull it out again and read the level.
• The oil should sit between the two marks. If it is at or below the lower mark, add oil in small amounts, a quarter of a litre at a time, and recheck after a couple of minutes.
• Use the exact specification in your handbook. Modern engines are specific about oil grade and manufacturer approvals, and the wrong oil can block a diesel particulate filter or damage variable valve timing.
• Note the colour and feel. Fresh oil is amber and slippery. Very black, gritty or milky oil needs attention, and milky oil on the dipstick or under the filler cap can point to coolant getting into the engine.

Oil changes themselves are within reach at home if you have ramps or stands, a drain pan and the right filter and sump plug washer. Two cautions. Used oil must go to a household waste recycling centre, not down a drain, and on a car under manufacturer warranty a self service can complicate a claim unless you keep receipts and follow the schedule exactly.

Engine oil does four jobs at once: it lubricates, it cools, it cleans by carrying combustion deposits to the filter, and it seals the piston rings against the bore. That is why an oil change replaces the filter as well as the fluid.

When do air filters and spark plugs need replacing?

Air filters are usually replaced at every major service or roughly every two years, sooner if you drive on dusty rural roads or in heavy traffic. A blocked filter starves the engine of air, which costs power and fuel.

Changing one is straightforward on most cars:

• Find the airbox, a large plastic housing connected to the engine by a wide pipe.
• Release the clips or screws holding the lid on and lift out the old filter, noting which way up it sat.
• Hold it up to the light. If very little light comes through, replace it.
• Wipe out any leaves and grit from inside the housing before fitting the new filter.
• Refit the lid squarely and make sure every clip is engaged. An air leak past a badly seated lid can trigger a fault light.

Spark plugs apply to petrol engines only, and modern long life plugs often run to a high mileage before replacement. Symptoms of tired plugs are rough idling, misfires, hesitation under acceleration and worse fuel economy.

• Work on a cold engine so the threads in the cylinder head are not at risk.
• Remove the coil pack or lead from the plug, one cylinder at a time so you cannot mix up the firing order.
• Blow or brush any debris out of the plug well before you unscrew the plug, so nothing falls into the cylinder.
• Use a proper spark plug socket with a rubber insert, and undo the plug with a smooth pull.
• Compare the old plug with the new one. Heavy black soot points to a rich mixture, oily deposits point to worn valve stem seals or rings, and a melted or blistered electrode points to overheating.
• Fit the new plug by hand first to avoid cross threading, then torque it to the figure in the handbook. Overtightening strips aluminium cylinder heads.

If the engine still misfires with new plugs, the fault is usually a coil pack, an injector or a vacuum leak, and that needs diagnostic equipment.

How do you look after your tyres?

Tyres are the only part of the car touching the road, so they get checked more often than anything else.

Pressures

Set them cold, using the figures on the placard in the driver door shut, inside the fuel filler flap or in the handbook. Ignore the number moulded into the tyre sidewall, which is the maximum the tyre can hold rather than the pressure your car needs. Most placards give a second, higher set of figures for a fully loaded car, and those are worth using for a holiday run.

Underinflation wears the tyre shoulders, raises fuel consumption and makes the tyre run hot. Overinflation wears the centre of the tread and reduces grip on wet roads.

Tread depth

The UK legal minimum is 1.6mm across the central three quarters of the tread, around the whole circumference. The usual home check is the 20p test: put a 20p coin into the main tread grooves, and if the outer band of the coin is hidden, you have more than roughly 3mm left. If you can see the band, get the tyre measured properly. Most tyres are worth replacing at 3mm because wet weather stopping distances lengthen sharply below that.

Also look for uneven wear, which tells you something else is wrong:

Rotation and alignment

Rotating tyres front to back evens out wear, since front tyres wear faster on most cars. Check first whether it applies to yours: many cars run different sizes front and rear, and directional tyres can only swap front to back on the same side. If you do it at home, use axle stands rather than trusting a jack, follow the pattern in the handbook, and torque the wheel bolts in a star pattern to the specified figure.

Get the alignment checked after any significant kerb strike, or whenever the steering pulls to one side or the wheel sits off centre on a straight road. Alignment is cheap; a set of tyres ruined by it is not.

Damage

Look for cuts, bulges and cracking in the sidewall. A bulge means the internal structure has failed and the tyre must be replaced, not repaired. Kerb damage to the wheel itself is a separate issue, and a badly kerbed rim can leak air past the bead as well as look untidy.

How do you keep a car battery healthy?

A battery in a car doing regular longer journeys will normally give four to five years. Short journeys are the killer, because the alternator never gets long enough to replace what starting the engine took out.

• Check the terminals every six months. White or blue green powder is corrosion, which raises resistance and can cause odd electrical faults.
• Clean corroded terminals with a stiff brush and a solution of bicarbonate of soda in warm water, rinse with clean water and dry thoroughly. Disconnect the negative lead first and reconnect it last.
• Make sure the clamps are tight and the battery is properly held down. A battery that moves about chafes cables and cracks its own case.
• Test the voltage with a multimeter across the terminals. A healthy battery that has been sitting reads around 12.6V. Below about 12.4V it is partly discharged, and below 12.0V it is flat.
• With the engine running, the same meter should read roughly 13.8V to 14.4V. Much lower and the alternator or its belt needs attention; much higher points to a regulator fault.
• If the car sits unused for weeks, a smart trickle charger keeps the battery conditioned far better than a monthly ten minute run.

On cars with stop start, the battery is usually an AGM or EFB type and needs replacing with the same type and coding to the vehicle. Fitting a standard battery to a stop start car generally ends with a short life and a permanently disabled stop start system.

What are the warning signs of worn brakes?

Squealing that stops when you brake, grinding, a pedal that sinks slowly or feels spongy, a car that pulls to one side under braking, or a pulsing pedal all mean the brakes need inspecting. Grinding in particular means the friction material has gone and the backing plate is cutting into the disc, which turns a pad replacement into a pad and disc replacement.

A visual check is possible on most cars through the wheel spokes: look at the thickness of the friction material on the pad against the metal backing. If it is down to a few millimetres, book it in. A proper inspection means taking the wheel off, and if you do that:

• Support the car on axle stands on level ground, never on a jack alone.
• Check pad thickness on both the inner and outer pad. The inner one often wears faster.
• Look at the disc surface for deep scoring, a pronounced lip at the outer edge, or heat cracking.
• Check the flexible brake hoses for cracking, chafing or bulging.
• Look for fluid seepage around the caliper piston seal, which means the caliper needs rebuilding or replacing.

Brake fluid deserves its own note. It absorbs moisture from the atmosphere, which lowers its boiling point, so it is replaced on time rather than on condition, generally every two years. Check the reservoir level with the bonnet up: a slowly falling level usually just reflects pad wear, but a rapid drop means a leak and the car should not be driven. Brake fluid strips paint on contact, so wipe up spills immediately and rinse with plenty of water.

Which fluids should you check?

Top coolant up with the correct type for your car and pre mixed to the right strength. Coolant is as much about corrosion protection and raising the boiling point as it is about frost, so plain water is a short term emergency measure only.

Are your lights and wipers legal?

Every exterior light must work and show the correct colour, and lights are one of the most common MOT failures. Check them fortnightly by turning everything on and walking round the car, using a wall or shop window to see the rear lamps if you are on your own.

• Test dipped beam, main beam, sidelights, indicators, hazards, brake lights, fog lights and reversing lights.
• Get someone to press the brake pedal, or reverse gently towards a wall or glass to see the reflection.
• Clean the lenses. Road film cuts light output noticeably, and badly hazed headlamp lenses can fail an MOT.
• Replace bulbs in pairs where you can, so the beam is even and the second one does not fail a fortnight later.
• Handle halogen bulbs with gloves or a cloth. Skin oil creates a hot spot on the glass and shortens bulb life.

Wipers are just as important. Replace blades that smear, chatter or leave lines, generally once a year, and keep the screen wash topped up with a proper additive so it does not freeze in winter. An empty washer bottle is an MOT failure.

How do you look after the interior and bodywork?

Bodywork and interior condition drive resale value more than any other visible factor, and both are easier to maintain than to restore.

• Wash the car every two to three weeks, more often in winter when road salt is on the roads. Use a proper car shampoo and two buckets, one for washing and one for rinsing the mitt.
• Rinse the wheel arches and underside during winter. Salt sitting in the arches and sills is what starts most corrosion on UK cars.
• Wax or seal the paint two or three times a year. It makes washing easier and gives bird lime and tar something to sit on other than your lacquer.
• Deal with stone chips promptly. Once the primer is breached, moisture reaches bare steel and the chip becomes a rust spot that costs far more to put right.
• Vacuum the carpets and mats regularly, and lift the mats out. Grit trapped underneath wears the carpet through.
• Treat leather with a proper conditioner two or three times a year, and use a matt protectant on the dashboard so it does not reflect into the windscreen.
• A drop of light oil or a spray of white grease on door hinges, bonnet catches and the boot latch stops squeaks and seized mechanisms.
• Keep the door and boot rubbers clean and treat them with a silicone product so they do not stick or tear in frost.

If the paint already looks dull, or the car is covered in fine swirl marks from years of quick washes, that is clearcoat damage rather than dirt and it responds to machine polishing. Where panels are dented, kerbed or corroded, body repairs put the surface back before the damage spreads. Both are worth doing before a sale or at the end of a lease, when cosmetic condition is priced directly into what you get back.

When should you stop and call a garage?

Some symptoms mean pull over rather than press on:

• Red warning lights for oil pressure, coolant temperature, charging or brakes.
• Steam or a strong sweet smell from under the bonnet.
• A brake pedal that goes towards the floor.
• A grinding or knocking noise that changes with road speed.
• Any smell of burning or fuel.

Amber lights generally mean get it looked at soon rather than stop immediately, but do not ignore them for months. An engine management light left on for a year usually means several stored faults by the time it reaches a diagnostic machine, and a car with a lit engine light will fail its MOT.

Above all, keep the handbook in the glovebox and use it. Service intervals, fluid specifications, tyre pressures, bulb types and fuse locations are all in there, and they differ far more between models than generic advice suggests.