Car Maintenance Checklist: What You Should Know Before a Long Trip

Almost nothing fails on a long drive without warning. The tyre, the battery, the perished hose were all saying something three weeks earlier, on a twenty-minute commute where it did not matter enough to bother. A pre-trip check is mostly a way of listening a little sooner, and of leaving yourself enough time to do something about what you hear.

Two weeks out: whatever needs a workshop slot

Start with the jobs you cannot finish yourself, because those are the ones that ruin a departure date. A brake pad you decide to replace the day before a trip is a brake pad you will drive on regardless, and that is exactly the compromise a checklist is supposed to prevent.

Tyres, measured rather than glanced at

Tread depth is the one legal threshold worth knowing by heart. In the UK, cars and light vans must keep at least 1.6 mm of tread across the central three quarters of the breadth, in a continuous band around the whole circumference, according to Annex 6 of the Highway Code. Most European countries apply the same 1.6 mm figure, and the United States works to 2/32 of an inch, which is close enough that the practical answer is the same: if a tyre is near the limit before a long trip, it will be past it by the time you come home.

Look for the uneven wear too. A shoulder worn faster than the centre, or one edge scrubbed flat, usually points at alignment or pressure rather than at the tyre itself, and replacing the rubber without fixing the cause just buys the same problem twice. Cuts, bulges and anything embedded in the tread go to a tyre fitter, not to a tyre inflator.

Brakes: the one section that is not a DIY section

New noises when braking are cheap information and expensive to ignore. A faint squeal on light braking, a pulse through the pedal, a pedal that travels further than it used to, or the car pulling to one side under braking are all reasons to book an inspection before a motorway trip, not after one.

We are deliberately not going to describe how to change pads or bleed a circuit here. Braking, steering and suspension work should go to a qualified mechanic, both because the consequences of a mistake are not recoverable at 70 mph and because a workshop will spot the seized caliper or the corroded line that a visual check from the outside never shows.

The battery, which almost never fails at a convenient moment

Batteries tend to die on the first properly cold morning or after a long stop somewhere with no phone signal. The warning signs are dull: slow cranking, headlights that dim noticeably at idle, a start/stop system that quietly stops working. Any of those is worth a free battery test at a parts shop, which takes about five minutes.

Clean, tight terminals matter more than most drivers expect. Corrosion on a terminal adds resistance, and a battery that is fine on a bench can still crank badly through a furred connection.

The final week: fluids, filters and glass

This is the part you can genuinely do yourself, on a cold engine, on level ground, in about half an hour.

Engine oil comes first, checked on the dipstick and topped to the upper mark with the grade your handbook specifies. Grade is not a detail: the US Department of Energy notes on fueleconomy.gov that using the manufacturer’s recommended oil grade rather than a thicker one is worth roughly 1% to 2% in fuel economy, which is a small thing that becomes a real thing over a thousand miles.

Coolant is checked at the expansion tank between the minimum and maximum marks, cold, with the cap left alone if the engine is warm. A level that keeps dropping is a leak, and a leak is a garage job rather than a top-up habit.

Brake fluid gets looked at, not adjusted. A level sitting near the minimum usually means the pads have worn down and the fluid has migrated into the calipers, which is another reason for that two-week garage booking rather than for a bottle from the shelf.

Then the unglamorous three: screenwash filled properly rather than with plain water, wiper blades replaced if they smear or chatter, and the cabin and engine air filters checked if they are due. A wiper that is merely acceptable in town is genuinely dangerous in motorway spray behind a lorry.

The night before: fifteen minutes, no more

Keep the last evening deliberately small, because a job you discover at nine in the evening is a job you will rush.

Check tyre pressures cold, before driving anywhere, against the plate in the driver’s door shut or the figures in the handbook. If you are carrying four adults and a full boot, use the laden pressures rather than the everyday ones, which are usually printed alongside. Inflate the spare while you are there, or check that the inflation kit in the boot has not passed its expiry date, because tyre sealant does expire.

Then walk around the car with someone pressing the pedals: headlights, main beam, sidelights, indicators, hazards, brake lights, reversing lights, fog lights, number plate lights. It takes two minutes and it is the single most common thing people are pulled over for on a trip.

Finally, the emergency kit. Warning triangle, high visibility vests for everyone on board rather than one for the driver, a working torch, jump leads or a jump pack, a first aid kit, and the jack and wheel brace actually present rather than assumed. Several European countries require the triangle and vest by law and the exact requirements vary by country, so it is worth checking the rules for anywhere you plan to cross.

The whole thing as a timeline

The check we skip most often, and what it costs

Honestly, the one that gets skipped in our own garage is the laden tyre pressure. Everyday pressures are set for a driver and maybe a passenger, and a fully loaded family car on a summer motorway run is a different vehicle: heavier, hotter and further from the tyre’s designed operating window. The result is a car that feels vague at the back, wears the shoulders of the rear tyres and drinks more fuel, all for the sake of a placard most people never read past the first line.

The second one is the walk around at the first fuel stop. Ten minutes into a heavily loaded trip is when a badly secured roof box, a rubbing tyre or a dragging exhaust makes itself known, and it is much easier to deal with in a service area than at the roadside two hundred miles later.

Questions drivers ask before a long run

Should I get a full service before every long trip?

Not necessarily. If the car is within its service interval and has no warning lights, a targeted check of tyres, brakes, battery and fluids is enough. If the service is due within a few thousand miles of the trip, bringing it forward is usually cheaper than the alternative.

How cold do tyres need to be for an accurate pressure reading?

Cold means the car has been parked for at least a couple of hours, or driven less than about two miles. Warm tyres read high, and letting air out of a warm tyre to hit the placard figure leaves you underinflated once it cools.

Is it worth topping up the air conditioning before a long summer drive?

Only if it is blowing noticeably less cold than it used to. Air conditioning is a sealed system, so a system that has lost gas has a leak, and a regas without finding the leak simply repeats itself next summer.

What should I do if a warning light comes on during the trip?

Red lights mean stop as soon as it is safe to do so, particularly oil pressure, coolant temperature and brake warnings. Amber lights generally mean the car has detected a fault and reduced something, so continue at a moderate pace and get it read at the next opportunity rather than pressing on for another five hours.

Does a roof box really change how the car needs to be checked?

It changes the pressures and the load, yes, and it also changes fuel consumption significantly. The Department of Energy puts the penalty of a roof cargo box at roughly 6% to 17% on the highway and up to 25% at higher interstate speeds, so plan fuel stops accordingly.

Last updated: 4 August 2026. Sources consulted: GOV.UK, The Highway Code, Annex 6 (vehicle maintenance, safety and security), for tyre tread depth requirements; US Department of Energy and EPA, fueleconomy.gov, for the figures on motor oil grade and roof cargo boxes. Regulations on tyres, warning equipment and roadside requirements vary by country and change over time, so check the rules that apply where you are driving.