Car maintenance for better fuel economy and longevity

There is a strong overlap between keeping a car running well and running it more sustainably. Every litre of fuel saved is money back in your pocket and CO₂ that was never burned. And a car that lasts an extra five years is one fewer car that had to be manufactured.

Why maintenance is a green issue

Most conversations about green motoring focus on what car you drive. But how you maintain the car you already own has a real and immediate impact on its environmental footprint.

A badly maintained car is one that burns more fuel per kilometre than it should, wears out parts faster and may emit more pollutants from its exhaust than a well-kept equivalent. Poor maintenance accelerates the point at which the car becomes uneconomical to repair and ends up being scrapped — which means another car has to be manufactured sooner.

Manufacturing a vehicle is resource-intensive. The raw materials, energy and processes involved represent a significant environmental cost before the car ever turns a wheel. Keeping an existing car in good condition for as long as possible spreads that embodied cost over more years and kilometres, which almost always compares favourably to the environmental cost of producing a replacement.

• Regular maintenance reduces fuel consumption, which directly cuts tailpipe emissions on every journey.
• A well-maintained car is far more likely to pass emissions tests without needing repairs.
• Longer vehicle life means fewer cars manufactured overall — a genuine reduction in resource use and industrial emissions.
• Cheaper to run: the cost of maintenance is almost always much less than the cost of major repairs caused by neglect, or premature replacement.

Tyre pressure and condition

Tyres are among the most important factors affecting both fuel efficiency and safety. They are also the easiest thing to check yourself, with no tools beyond a tyre pressure gauge — available cheaply, or free to use at most petrol stations.

Alongside pressure, check the condition of your tyres regularly:

• Tread depth. The legal minimum tread depth varies by country (in the UK and EU it is 1.6 mm across the central three-quarters of the tyre). Tyres become progressively less effective in wet conditions as the tread wears. Most experts recommend replacing before the legal minimum — around 2–3 mm is a commonly suggested practical threshold for wet-weather safety.
• Sidewall condition. Look for cracks, bulges or cuts in the sidewall. A bulge indicates internal structural damage and means the tyre should be replaced as soon as possible.
• Uneven wear patterns. Wear that is heavier on one edge or in patches often indicates incorrect inflation, misaligned wheels or a suspension problem — all of which increase fuel use and accelerate tyre wear further.
• The spare. Check the pressure and condition of the spare tyre or emergency inflation kit at the same time — you don't want to discover it's unusable when you need it.

Regular servicing and engine oil

Following the manufacturer's recommended service schedule keeps the engine running as it was designed to. Skipping or delaying services might feel like a saving in the short term, but costs more in increased fuel use and the risk of larger repair bills.

• Engine oil. Oil lubricates moving metal parts inside the engine, reducing friction. Over time, oil degrades — it becomes thicker, less effective and contaminated with small particles. Dirty or low oil increases friction, which means the engine works harder and uses more fuel. Checking the oil level monthly (using the dipstick, with the engine cold and the car on level ground) and changing it at the recommended interval is one of the simplest and most important maintenance tasks.
• Oil grade matters. Use the grade specified in your car's handbook. Modern engines are often designed for lower-viscosity (thinner) oils that reduce internal friction; using the wrong grade can measurably affect efficiency.
• Coolant level and condition. Correct coolant prevents the engine overheating, which causes damage and excess fuel use. Check the level at the reservoir and top up with the correct coolant type if needed.
• Brake fluid. Brake fluid absorbs moisture over time, which lowers its boiling point and can compromise braking performance. Most manufacturers recommend changing it every two years regardless of mileage.

Air filter and spark plugs

Two components that are commonly overlooked outside of a full service have a direct effect on how cleanly and efficiently the engine burns fuel.

• Air filter. The engine needs a steady supply of clean air to mix with fuel for combustion. A clogged air filter restricts airflow, which forces the engine to work harder and can cause incomplete combustion — both reducing efficiency and increasing exhaust emissions. Air filters are inexpensive and straightforward to check. On many cars the filter housing is visible and accessible without tools. If the filter looks grey or brown rather than light-coloured, it is worth replacing.
• Spark plugs (petrol engines). Spark plugs ignite the fuel-air mixture inside the cylinder. Worn or fouled spark plugs cause misfires — partial or failed combustion events — which waste fuel directly and can damage the catalytic converter over time. Modern iridium or platinum plugs last much longer than older copper plugs, but should still be checked and replaced at the recommended interval.
• Diesel fuel systems. Diesel engines have their own equivalents: fuel filters that can restrict flow if neglected and glow plugs that help with cold starts. Follow the service schedule for these.

Wheel alignment and brakes

Two further factors that quietly add to fuel consumption and running costs:

• Wheel alignment. If the wheels are not pointing in exactly the right direction, the tyres scrub sideways slightly as the car moves forward. This increases rolling resistance, wears tyres unevenly and wastes fuel on every journey. Alignment can be knocked out by kerbs, potholes and minor impacts. It is worth checking at least once a year and after any significant suspension impact. Signs of misalignment include the car pulling to one side on a straight road, or faster-than-expected tyre wear on one edge.
• Brake condition. Worn or sticking brakes create drag, meaning the engine is constantly working against the brakes even when you think you're not braking. A brake that sticks slightly can cause uneven tyre wear and a noticeable increase in fuel use. Brakes should be inspected as part of regular servicing; act on any squealing, grinding or pulling when braking.

Remove excess weight and roof racks

Every kilogram the engine has to move adds to fuel consumption. A car carrying unnecessary weight on every journey is less efficient than it needs to be.

• Clear the boot of items that travel everywhere but are rarely needed — sports equipment, tools, heavy bags, old child seats. The fuel saving across a year of daily driving adds up.
• Remove roof racks and roof boxes when not in use. These create aerodynamic drag in addition to adding weight. A roof box or large roof rack at motorway speed can measurably increase fuel consumption. If you only use the roof rack a few times a year, the simple act of removing it between uses saves noticeably over time.
• Bike racks mounted to the rear of the car also create drag, though less than a roof-mounted load. Remove them when the bikes are not being carried.

Act on warning lights promptly

Dashboard warning lights exist because the car's systems have detected something that needs attention. Ignoring them can turn a minor issue into a costly repair — and many faults directly increase fuel consumption and emissions in the meantime.

• Engine management light (check engine). This can indicate anything from a loose fuel cap to a faulty oxygen sensor or catalytic converter issue. A faulty oxygen sensor, for example, can cause the engine to run with the wrong fuel-to-air ratio, which significantly increases fuel consumption and emissions. Many garages and auto parts shops can read the fault code for free or a small fee.
• Tyre pressure warning light (TPMS). On cars fitted with a tyre pressure monitoring system, this light means at least one tyre is significantly underinflated. Check pressures immediately — don't continue driving and assume it will resolve itself.
• Oil pressure and temperature warnings. These are more serious — stop as soon as it is safe to do so and investigate before continuing.

Keep your old car or buy a new one?

This is one of the more genuinely complex sustainability questions in personal transport — and there is no universal answer. The honest answer depends on your specific car, its condition and what you would replace it with.

Manufacturing a car requires significant energy and raw materials. This embodied carbon is roughly equivalent to several years' worth of tailpipe emissions from the car once it is on the road. This means that if you scrap a functional car to replace it with a newer, slightly more efficient model, you may not actually reduce total emissions for several years — if at all.

• Keeping a reasonably efficient, well-maintained older car is usually greener than replacing it with a similar petrol or diesel model — the manufacturing footprint of the new car outweighs the modest fuel saving for a long time.
• The case for switching is stronger when replacing a high-mileage, old and genuinely inefficient vehicle — particularly with a much lower-emission option. See our electric cars guide for an honest look at the EV case.
• A car that becomes too expensive to repair — where the cost of fixing it exceeds its value — is a different situation. At that point, replacement makes sense economically and the environmental calculation shifts accordingly.
• Keeping a car for more total years by maintaining it well is almost always the lower-footprint option compared to frequent replacement cycles.

What applies to electric vehicles

EVs require far less maintenance than internal combustion engine cars — no oil changes, no spark plugs, no exhaust system, and regenerative braking reduces brake wear considerably. But several maintenance tasks still apply and are just as important for efficiency and longevity.

• Tyre pressure. Equally important in an EV — rolling resistance affects range directly. Many EVs use low-rolling-resistance tyres, and maintaining correct pressure is essential to getting the stated range.
• Tyre wear and weight. EVs tend to be heavier than equivalent petrol cars due to the battery pack, which can accelerate tyre wear. Check tread depth regularly and remove unnecessary weight and roof loads — range impact at speed is real.
• Coolant and brake fluid. EVs still have coolant systems (for the battery thermal management) and hydraulic brakes. These still need checking and periodic replacement.
• Battery care. Avoid routinely charging to 100% or regularly depleting to near zero if the manufacturer recommends a lower daily charge limit. Keeping the battery in its preferred range (often around 20–80%) extends its long-term health. See our electric cars guide for more on getting the most from an EV battery.

End-of-life: responsible recycling

When a car finally reaches the end of its useful life, responsible disposal matters. A vehicle contains fluids, metals and materials that should not go to landfill — and most of the metal content is recyclable.

• Use an Authorised Treatment Facility (ATF) — the terminology varies by country, but the principle is the same: facilities licensed to safely drain fluids, remove hazardous components and maximise material recovery.
• A Certificate of Destruction (or equivalent) should be issued when a car is scrapped — this removes it from the register of vehicles and confirms it has been processed correctly.
• If the car is driveable and has useful life left, selling or donating it extends that life rather than sending it for scrap — the lowest-footprint outcome.
• For EVs, the battery is the most resource-intensive component. A growing network of second-life battery programmes repurposes EV batteries for stationary energy storage before they are finally recycled.

Your monthly car check

1. Check all four tyre pressures (and the spare) with a gauge, when cold. Inflate to the manufacturer's recommended pressures.
2. Inspect each tyre visually — look at tread depth, sidewall condition and the wear pattern across the tread surface.
3. Check the engine oil level on the dipstick with the engine off and the car on level ground. Top up with the correct grade if needed.
4. Check the coolant level at the reservoir. It should sit between the minimum and maximum marks when cold.
5. Check all lights — headlights, brake lights, indicators, fog lights. Walk around the car or ask someone to help.
6. Check windscreen washer fluid and top up if low. A smeared windscreen reduces visibility significantly.
7. Note any dashboard warning lights that have appeared and investigate them promptly rather than leaving them.
8. Remove anything from the boot or car that you have been carrying unnecessarily. Check whether the roof rack can come off.

• Tyre pressures checked and set to the correct figure.
• Tyre tread and sidewalls inspected — no damage, sufficient depth.
• Engine oil at the correct level, changed on schedule.
• Coolant and brake fluid checked.
• All lights working.
• Air filter inspected and replaced when dirty.
• Wheel alignment checked at least annually.
• Roof rack and bike rack removed when not in use.
• Boot cleared of unnecessary weight.
• Warning lights investigated and resolved promptly.

Combine good maintenance with eco-driving habits and you have two complementary approaches: one keeps the car in good mechanical condition, the other makes the most of it on every journey.