Vehicle Safety Check: A Step by Step Guide for UK Drivers

Most roadside breakdowns and a good share of MOT failures come from things a driver could have spotted in a car park with a torch. Tyres below the limit, a blown bulb, a coolant level that has quietly dropped, a wiper blade that smears. None of them are difficult to find. They just need looking for on a regular basis rather than on the morning of the test.

This is the check we would run on a car before handing it back to a customer, adapted so you can do it yourself on your own drive.

How often should you do a vehicle safety check?

Once a month, and again before any long journey. That cadence catches slow changes such as a tyre losing a few PSI a week or an oil level creeping down, while they are still cheap to deal with.

Add a check in these situations too:

• After hitting a pothole or kerbing a wheel, even at low speed
• Before and after towing
• At the start of autumn, before the first cold, wet, dark commute
• Before an MOT, so you can fix the obvious items first
• After the car has stood unused for more than a few weeks

What do you need for a vehicle safety check?

A torch, a tyre pressure gauge, a pair of gloves and a clean rag will cover ninety percent of it. Keep them together so the check does not get skipped.

• Torch. A head torch is better than a hand torch, because it leaves both hands free under the bonnet and under the wheel arches.
• Tyre pressure gauge. A cheap pencil gauge is fine. Forecourt airlines are frequently out of calibration, so a gauge of your own is worth having.
• Gloves. Nitrile or mechanics gloves. Coolant and used oil are not things you want on your hands.
• Clean rag or paper towel. For the dipstick and for wiping a suspected leak so you can see whether it comes back.
• A 20p coin. The quickest tyre tread check there is.
• Wheel brace, jack and locking wheel nut key. Not for the check itself, but confirm they are in the car and that the key fits. Discovering the locking nut key is missing on a hard shoulder is a bad day.

Do the check on level ground with the engine cold, or at least an hour after it was last run. Hot coolant is under pressure and will scald you.

What to check under the bonnet

Work through the fluids first, then the battery, then the belts and hoses. Everything under the bonnet is either a level, a connection or a piece of rubber that perishes.

Engine oil. With the car level and the engine cold, pull the dipstick, wipe it, reinsert it fully and pull it again. The level should sit between the minimum and maximum marks. Oil that is very dark and thin, or that smells of petrol, is due a change. Many modern cars have an electronic oil level readout instead of a dipstick, in which case use the dashboard menu.

Coolant. Check the expansion tank level against the cold mark on the side. Never open the cap on a warm engine. A level that keeps dropping with no visible puddle usually means a leak somewhere pressurised, or in the worst case a head gasket. Coolant should look clear and brightly coloured, not brown or sludgy.

Brake fluid. Level between minimum and maximum in the reservoir. Brake fluid drops slowly as the pads wear, which is normal, but a sudden drop means a leak and the car should not be driven. Fluid that has gone dark brown has absorbed water and needs changing regardless of level.

Screenwash. Top up with a proper screenwash concentrate rather than plain water. Water alone freezes, encourages algae in the bottle and does not shift road film. An empty washer bottle is also an MOT failure.

Battery. Look for white or blue crusty deposits on the terminals, clean them off, and check both clamps are tight enough that you cannot twist them by hand. A battery over four or five years old that struggles on a cold morning is telling you something. Most garages and parts shops will test one for free.

Belts and hoses. With the engine off, squeeze the main radiator hoses. They should feel firm and springy, not soft, sticky or rock hard. Look along the auxiliary belt for cracking across the ribs, glazing on the flat side or missing chunks. Rubber that has gone shiny is on borrowed time.

How to check tyres and wheels

Tyres are the only part of the car touching the road, so they matter more than everything else on this list combined. Check all five, including the spare or the inflation kit.

Pressure. Set pressures cold, using the figures on the sticker inside the driver's door shut, inside the fuel filler flap or in the handbook. Do not use the number moulded into the tyre sidewall, which is a maximum rather than a recommendation. Most cars list a higher pressure for a full load, which is what you want before a family holiday.

Tread depth. The UK legal minimum is 1.6mm across the central three quarters of the tread, around the whole circumference. Push a 20p coin into the main grooves: if the outer band of the coin disappears, you are above the limit. If you can see the band, the tyre is close to or below it and needs replacing. Grip in the wet falls away noticeably long before 1.6mm, so most tyre fitters suggest replacing at 3mm.

Condition. Look for cuts, bulges in the sidewall, embedded nails and cracking between the tread blocks. A bulge is an internal structural failure and the tyre must be replaced immediately, whatever the tread looks like.

Wear pattern. Wear tells you about the rest of the car:

Wheels. Run a hand round each rim for kerb damage, and look for buckling or cracks, particularly after a pothole. A bent rim causes a slow puncture that keeps coming back and a vibration at speed that people often blame on the tyres. Corroded lacquer on a diamond cut wheel lets water under the finish and the white blooming spreads, so it is worth catching early. We cover both in our alloy wheel refurbishment service.

How to check the lights and signals

Every exterior light must work, and the lens must be clear enough to let the light out. Doing this alone is easy if you park facing a wall or a shop window at dusk.

• Sidelights, dipped beam and main beam
• Front and rear fog lights
• Indicators on both sides, plus hazards
• Brake lights, including the high level one. Press the pedal with a brick or ask someone to watch
• Reversing lights
• Number plate lights, which fail the MOT surprisingly often

Replace bulbs in pairs where you can, because the second one is usually not far behind. Cloudy, yellowed headlight lenses reduce output significantly and can fail the MOT on light pattern. They can be restored rather than replaced in most cases.

How to check brakes and suspension

Brakes should feel firm and consistent, and stop the car in a straight line without noise. Test them properly at low speed somewhere safe rather than guessing.

• Press the brake pedal hard with the engine off. It should feel firm and not sink slowly to the floor
• Start the engine. The pedal should drop slightly then hold. If it does not, the servo may not be working
• At walking pace, brake firmly. The car should stop square, not pull to one side
• Listen for grinding, which usually means the pads are gone and you are into the discs, and for a rhythmic squeal, which can mean a warped disc
• Apply the handbrake on a slope and make sure it holds the car. Electronic parking brakes should engage and release without warning lights

For suspension, push down hard on each corner of the car and let go. It should return to level and settle in one movement. If it carries on bouncing, the shock absorber on that corner is worn. Look behind each wheel for an oily film running down the damper body, which is the giveaway for a leaking unit. Clunks over speed bumps generally point to worn drop links or bushes.

What to check inside and outside the car

Inside, the priority is the restraint system and your view out. Outside, it is glass, wipers and the condition of the body.

Seat belts. Pull each belt out fully and look along the webbing for fraying, cuts and fading. Tug it sharply and confirm the inertia reel locks. Check each buckle clicks home and releases cleanly.

Airbag warning light. It should illuminate at ignition on and go out shortly after the engine starts. If it stays on, the airbags may not deploy in a collision and the car will fail its MOT.

Windscreen. Damage larger than 10mm in the area swept by the driver's side wiper, or larger than 40mm elsewhere in the swept area, is an MOT failure. A small chip can usually be resin filled cheaply. Left alone through a cold snap, it spreads into a crack and the whole screen needs replacing.

Wipers. Blades that judder, smear or squeak are past it. Lift each blade and run a fingertip along the rubber edge, feeling for splits and hardened spots. Check the washer jets actually reach the glass.

Mirrors and glass. All mirrors present, secure and adjustable. Clean the inside of the windscreen as well as the outside, since the film that builds up inside is what causes the worst glare at night.

Bodywork. Look along the panels in low light for stone chips on the bonnet and front wings, and for rust bubbling at wheel arch lips, sill edges and around the tailgate. Chips are cosmetic until the primer is breached, at which point corrosion starts underneath and spreads. Early stone chip repair is far cheaper than a panel respray later.

What do different fluid leak colours mean?

The colour and position of a puddle usually identifies the system before you get anywhere near a diagnostic tool.

Put a sheet of cardboard under the car overnight if you are not sure where a drip comes from. It shows both the colour and the position clearly.

What emergency equipment should you carry?

A basic kit turns a roadside problem into an inconvenience rather than an ordeal.

• Jack, wheel brace and locking wheel nut key, or the tyre sealant kit if the car has no spare
• Warning triangle, which is required in many European countries and useful here
• High visibility jacket, kept in the cabin rather than the boot so you can put it on before getting out
• Torch with working batteries
• Jump leads or a lithium jump pack
• First aid kit, checked for in date contents
• In winter: a blanket, a scraper, de-icer, a small shovel and something to eat and drink

How to check the exhaust system

The exhaust should be quiet, securely mounted and free of visible holes. Start the engine cold and listen from outside the car.

A blowing exhaust makes a hard chuffing or rasping note that rises with revs. Look along the system with a torch for soot streaks around joints, which mark the point where gas is escaping, and check that the rubber mounting hangers are intact rather than perished. Rust on the outer skin of a silencer is normal on a UK car after a few winters of road salt. Rust you can push a finger through is not. An exhaust leak ahead of the cabin can push carbon monoxide inside the car, so it is not a fault to live with.

How to check the steering and electrics

Steering should be light, precise and free of play, with the wheel returning to centre after a turn. With the engine running and the car stationary, turn the wheel slowly from lock to lock and listen for knocking or whining.

Excessive free play at the straight ahead position points to worn track rod ends or a steering rack. A whine on lock in a car with hydraulic power steering is often low fluid, so check that reservoir too. Most modern cars use electric power steering and have no fluid to check, but they do have a warning light: if it stays on, the assistance may cut out and the MOT will fail.

For the electrics, check the terminals as described earlier, look for chafed or brittle wiring near the battery and the bulkhead, and confirm interior items such as the heater blower, heated rear screen and windows all work. Fuses that blow repeatedly are a symptom, not the fault.

What to look for underneath the car

Rust is the main enemy on a British car, because road salt spends five months a year sitting in the seams. Kneel down with a torch and look along the sills, the jacking points, the suspension mounting areas and the boot floor.

Surface rust on a subframe is expected and largely cosmetic. Flaking, layered rust that you can pick at, or rust anywhere within 30cm of a structural mounting point, is an MOT concern and a safety one. Also look for split rubber gaiters on driveshafts and steering joints. Once a gaiter splits, grit gets in, and a cheap rubber boot becomes an expensive joint.

What to check on a test drive

Drive the car for ten minutes somewhere you can safely brake, accelerate and turn, and use your ears rather than the stereo.

• Brakes: straight stopping, no pulling, no vibration through the pedal
• Steering: no vibration through the wheel at 50 to 70mph, which usually means wheel balance
• Acceleration: smooth, no hesitation, no flat spots
• Gearchange: clean engagement, no crunching, no slipping under load
• Noises: clunks over bumps, humming that changes with cornering (wheel bearings), rattles at low speed
• Dashboard: all warning lights out once running

When you get back, park up and let the engine cool, then have a last look underneath and under the bonnet. Fresh fluid on the ground after a drive, when there was none before, tells you a lot.

Winter and seasonal checks

Cold, wet and dark conditions expose faults that a car gets away with in summer. Before the clocks go back, add these to the routine.

• Have the battery tested. Cold cranking is what kills a marginal battery
• Check antifreeze concentration, not just coolant level. A garage can test it in seconds
• Switch to a winter screenwash mix rated for the temperatures we actually get
• Replace wipers if they are borderline, because you will be using them constantly
• Check tyre tread with an honest eye. Wet grip is the thing that disappears first
• Wash the underside and wheel arches regularly to clear road salt, which is what turns a stone chip into a rust hole

If the check turns up cosmetic damage rather than mechanical faults, that is our side of the trade. We handle bumper scuffs, dents, kerbed wheels and rust repairs from our body shop in Radcliffe or on a mobile basis across Greater Manchester and the surrounding counties. You can see the full range on our vehicle body repairs page.