How to buy a used car in the UK - a practical guide

Step 1

Park your ego

The most important thing you can do before looking at a single car is detach from desire. Owning a car - especially an older, more characterful one - can be expensive. The running costs, the maintenance, the unexpected repairs. If you start with a car you want rather than a car you can genuinely afford to own, you'll end up with something that costs you more than it should.

That doesn't mean buying something dull. It means being honest about what you can sustain - not just the purchase price, but the ongoing cost of running that car well.

Step 2

Research the brand's reputation before you fall in love with a model

Every car brand has a character. Some are known for building things that last. Others have a reputation for expensive failures at certain ages or mileages. Before you go any further, spend time understanding whether the brand you're looking at is known for quality and longevity - and what the community says about the specific model you're considering.

The forums are your friend here. Owners Club communities, PistonHeads model-specific threads, and Reddit are filled with people who have owned these cars for years and know exactly what goes wrong. Read them before you book a viewing, not after.

What you're looking for: what are the common faults at the age and mileage you're targeting? If you know what you're likely to have to fix, you're in an informed position. You can price it in, budget for it, and decide whether it's manageable - rather than being blindsided six months after you buy.

Step 3

Service history is not optional

This is non-negotiable. The car must have a full service history. If it doesn't, walk away.

A service history tells you what has been done to the car, when, and by whom. Without it, you don't know what you're inheriting. An engine that looks clean and runs fine can be hiding a ticking clock - a component that was never replaced when it should have been, oil that hasn't been changed in 15,000 miles, a timing belt that's overdue.

Ideally, the history is stamped by franchised dealers or specialist independent garages, not just receipts in a folder. Look at the intervals - are they serviced on schedule? Any unusual gaps in the history? Those gaps are often where the problems live.

Here's a point most buyers miss: a high-mileage car with a full service history is often more reliable than a low-mileage car without one - particularly in older cars. Miles aren't the enemy. Neglect is. An engine that has been serviced regularly and driven consistently will frequently outlast a low-mileage equivalent that has sat unmaintained, run on old oil, or been used only for short cold-start journeys. The history is the proof of care. The mileage is just a number.

Step 4

Check for fault codes with an OBD reader

An OBD (on-board diagnostics) reader plugs into a port under the dashboard - usually found near the steering column - and reads any fault codes stored in the car's computer. You can buy a basic one online for under £20, or use a Bluetooth version with a free app on your phone.

Ask the seller if you can plug one in before you commit to a test drive. Any seller worth buying from will agree. A car with hidden fault codes will often appear to run fine on a short drive - the codes are the tell.

Not every fault code is catastrophic - some are minor sensor issues. But any code that the seller can't explain should be a flag, and any code relating to the engine, transmission, or emissions should make you pause and dig deeper.

Step 5

Check the history with CarVertical

Before you hand over any money, run the car's registration through CarVertical (carvertical.com). A history check tells you whether the car has been written off, has outstanding finance, has had its mileage clocked, or has been involved in accidents that weren't declared.

It costs a few pounds and takes two minutes. The information it surfaces can save you from inheriting someone else's problem - or from buying a car that isn't legally the seller's to sell.

Step 6

Inspect the condition - know what you're looking at

The visual inspection of a car is less about cosmetics and more about what the condition tells you about how the car has been looked after.

Paint consistency. Walk around the car in good light. The paint should be the same shade on every panel. Mismatched paint - even slightly - can indicate a previous repair or panel replacement after an accident.

Panel gaps. Look at the gaps between panels - bonnet to wing, door to sill, boot lid to quarter panel. They should be even and consistent on both sides. Large or uneven gaps can indicate structural repairs or poorly fitted replacement panels.

Rust. This matters more than most buyers realise, particularly on older UK cars where salt and road grime do their worst.

If you have any doubt about the condition of the underside, get the car up on a lift before committing. Many independent garages will do a pre-purchase inspection for £50-£100. On a car worth thousands, it's money well spent.

Step 7

Think about running costs, not just purchase price

Fuel consumption. Check real-world miles per gallon for the car you're buying - not the manufacturer's official figures, which are almost always optimistic, but owner-reported figures from forums and sites like Fuelly. A car that costs £2,000 more to buy but does 10mpg better can pay back that difference inside a year if you're doing decent mileage.

Servicing intervals. Budget to service your car every 6,000 miles, not 10,000 - regardless of what the manufacturer says. Variable service intervals on modern cars can extend to 10,000 miles or more, but they're optimised for convenience, not longevity. Shorter intervals with a quality oil are the single easiest way to extend the life of your car.

Insurance and tax. Check insurance costs before you fall in love. Some practical family cars sit in surprisingly high insurance groups. Check before you commit.

Step 8

Diesel or petrol - match the fuel type to how you actually drive

This one question eliminates a lot of expensive mistakes. The answer comes down to how you use the car - not which fuel costs less at the pump.

If you mostly do short trips - school runs, local errands, town driving - buy petrol. Diesel engines are designed to be run hard and hot. When they spend most of their life on short cold journeys, they accumulate carbon deposits in the DPF (Diesel Particulate Filter) and EGR valve. The DPF needs to reach a sustained temperature - typically at 50mph or above for a period - to burn off the soot it collects. If that never happens, the filter blocks. A blocked DPF can cost anywhere from £500 to over £2,000 to fix depending on the car. These are not freak failures - they are the predictable result of using a diesel engine for the wrong job.

If you do a long daily commute or regular motorway miles - diesel is worth considering. Driven properly, a diesel will run hot, keep itself clean, and return excellent fuel economy on long runs. The engine is doing what it was built for.

Step 9

Manual or automatic - easier to drive is not the same as easier to own

An automatic is more convenient to drive, particularly in traffic. But convenience has a cost, and it's worth understanding what that cost looks like before you commit.

Manual gearboxes are simpler and cheaper to maintain. The clutch is the main wear item - it's predictable, well understood, and the repair cost is known. The gearbox itself, if not abused, is robust and long-lived. When something goes wrong with a manual gearbox, it is usually diagnosable and fixable at a reasonable cost.

Automatic gearboxes are more complex and can be expensive to repair when they go wrong. Traditional torque converter automatics are generally the most reliable. Dual-clutch gearboxes (DSG, PDK, DCT) offer quick, efficient changes but have a less forgiving reputation at higher mileages or when servicing has been neglected. CVT transmissions - common in smaller automatics - can also be costly to replace when they fail.

None of this means you should avoid an automatic - but if you're buying one, factor in the potential cost of gearbox repair and check the service history specifically for gearbox oil changes. It's one of the most commonly skipped service items and one of the most important for longevity.