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31 March 2021

How to buy the best used car

Buying a used car can not only save you a fortune in depreciation, but also put your dream car within reach. We'll help you buy the best used car at the right price.
Used car dealer
Daljinder Nagra

Buying a used car over a box-fresh model is an easy way to save money on the purchase price due to the huge depreciation that cars suffer - particularly in those initial years after first registration.

If you’re not fussy about driving something brand new, it can be a convenient way to make big savings over a comparable new car, or to trade up into something that might otherwise be financially out of reach.

Unless you’ve got very specific needs, there’s usually a ready supply of suitable, good-quality used cars. And you can normally drive away as soon as the deal is done.

Of course, buying a used car is not without potential problems. This guide explains what to look out for – including assessing how reliable any potential purchase is likely to be, and how to ensure you get the best used car for your needs.

We've rounded up the best used (and new) cars by class, to help you quickly find your ideal car. We also highlight the worst cars to avoid. Take a look at our expert pick of the best cars.

Is it worth buying a used car?

Buying a used car is the cheapest way to buy a car in the long run. That's provided you’re diligent, don't pay over the odds for it and choose a reliable model - which we can help you with.

New cars lose an incredible amount of value when they’re first registered. Typically a new car could be worth as little as 50% of its original value in just three years – a nightmare for the first owner, but a blessing for used car buyers.

That said, buying a used car can be the riskiest way to buy a car, as it can sometimes be tricky to know how well it’s been looked after, and if it has a hidden history – more on both below. You can easily find out which cars are the most dependable as they age, as our unique annual survey of thousands upon thousands of drivers reveals the most reliable cars.

Buying used is likely to be your only way into a conventional petrol or diesel car after the 2030 ban on new combustion engines. If you’re concerned that an electric car doesn’t suit your needs, buying the correct used car could see you well into the future. 

But make sure you check its emissions levels first. Our independent tests, which we believe better reflect real-world driving when compared to the official tests, will help you pinpoint the high-emission cars to avoid, and the low-emission cars you should consider.

What to look for when buying a used car

Regardless of how few miles a used car may have on it, its care and maintenance will once have been the responsibility of someone else. It’s worth taking the time to do your research so you don’t end up with a car you can't rely on.

Our most recent car survey highlighted the four most common faults reported on used cars - read on to find out what these are, and how to look out for them: 

1. Suspension components

Springs and dampers are the components responsible for cushioning a car’s ride. They can wear out as they age, particularly if they’ve lived a hard life. We found it was the most common issue in cars more than nine years old - it affected around one in 10 cars that age in our survey.

The only real way to diagnose potential suspension issues is by taking a thorough test drive over a variety of surfaces and speeds. Look out for any knocking or thumping noises, jolts in the cabin or particularly baggy handling. These could all point to an expensive repair bill in the near future.

2. Flat batteries

Battery problems are pretty inevitable as a car ages, but it’s fairly easy to catch the issue early before being left with a car that won’t start.

The easiest way to check a car’s battery is in good health is simply to start the car. It could mean there’s a battery problem if the engine struggles to start, the starter motor isn’t working as hard as usual, or the interior or exterior lights dim significantly during ignition.

If your battery is too flat to turn the engine over, you may need to jump start it – watch our video and find out how to jump start your car safely. You may even replace the battery altogether, depending on its age and condition.

3. Exhaust and emissions

Visible smoke from the exhaust pipe of a car that otherwise seems to be running fine can be a warning sign of underlying issues. Blue and black smoke are of particular concern.

  •  Blue smoke suggests your car is burning engine oil, pointing towards failing seals and gaskets
  •  Black smoke is a result of a number of issues, but ultimately means your car isn’t burning fuel at the correct rate.

Exhaust/emission issues might also be diagnosed by listening to the engine as it starts – is there excessive or unusual noise? If so, this could be a sign of a ‘blowing’ exhaust, which is a result of corrosion causing small holes in the pipe.

4. Used car air conditioning

Air conditioning needs regular use and occasional maintenance to ensure it remains effective and clean over time.

Typically, loss of cooling can be remedied by a ‘re-gas’, which will refresh the coolants required by the system. If the air-con isn’t blowing even remotely cold, it could be a fault with the air conditioning unit itself – which is far more expensive to replace.  

If the air conditioning system hasn’t been used regularly there’s a chance it could develop mould and other bacteria in your ventilation system. If the car whiffs of cheese or old socks when you’ve got the air-con on, this is the most likely cause.  

For our full guide on things to look for, head to how to check and test drive a used car.

Are used electric cars a good buy?

Just like a petrol or diesel car, an EV will depreciate as it ages. This can make the earliest models – the likes of the Peugeot iOn, Renault Fluence and first-generation Nissan Leaf – very tempting indeed, particularly when compared with the relatively high list prices of current-generation models.

You'll need to consider your needs carefully, though, as even when they were new early models such as these didn't offer particularly useful driving ranges - something that won't have improved as they age. Some very early cars such as the Fluence don't even have rapid charging capability.

Furthermore, if you're looking at a used Renault Zoe or an early Nissan Leaf model, it might be subject to a battery lease agreement, which was originally offered to lower the initial purchase price of the car.

Our latest research* into used electric cars, based on more than a thousand electric car owners, has shown there is a very slight but noticeable decline in useable battery range for older electric cars:

  • 98% battery capacity - electric cars up to three years old 
  • 92% battery capacity - electric cars at seven years old

We will continue to monitor the state of battery degradation as we collect more data. While an 8% reduction in usable range over six years might not be a deal-breaker, it’s something to think about if you’re considering a used electric car, or want to keep it for the long-term. Although it will not be an issue if your car will still have a decent range for your needs.

*(Survey: Dec 2019 to Feb 2020; 1,016 electric car owners, with vehicles across class types)

If you’re ready to take the plunge and buy a zero-emissions car, we will help you pick the perfect new or used model for your budget and needs - go to the best electric cars.

Where to buy a used car

There are a number of ways to source your used car, and you don't necessarily need to take a punt on the classifieds if you’re concerned about inspecting the quality for yourself.

Buying from a used car dealer

Buying an approved used car from a manufacturer's franchised dealer is usually the most expensive used option, but the car should have been checked thoroughly, and it will come with a warranty of typically around a year (or the remainder of the new warranty if the car is new enough).

Approved used cars will almost always have a full, up-to-date service history, so you can be assured it’s been well looked after.

Independent car dealers can offer lower prices and more choice, as they’re not tied to a particular brand. However, any warranty offered may be limited and the quality of the cars can be more variable.

Be wary of buying a warranty provided by a third-party (as typically sold by independent dealers). We've found they can offer poor value - see should you buy a used car warranty for more information.

How to buy a used car from a private seller

You’ll typically get the lowest price (particularly if you sharpen your haggling skills) by buying from a private seller, who should be the car’s current owner.  

Going this route means cars are ‘sold as seen’ - so you will have very little legal comeback if things go wrong, unless the seller has been misleading in their description of the car or its condition. 

Something to also bear in mind if you're buying privately is that a seller isn't legally obliged to tell you if they haven't had their car fixed due to a recall. Manufacturers often launch recalls to address specific issues that have emerged over a vehicle’s lifetime. While this can be concerning, a car having been recalled isn’t necessarily a bad thing (it’s a manufacturer being proactive about the safety of its products after all) – provided there aren’t any outstanding recalls on it.

Safety-related recalls cover a wide variety of vehicle components. In recent times, a fault (with potentially fatal consequences) related to Takata airbags has seen hundreds of thousands of cars across multiple manufacturers, recalled globally. 

Not all recalls are as serious, but it’s worth checking any car has had the work done before you buy. You can do this by entering the car's registration into the government recall check tool.

You will have to arrange insurance cover to legally test drive a car offered by a private seller, if your own insurance policy doesn’t include third-party cover on additional vehicles.

Used car auction

A car auction could be the cheapest way to buy a used car. Auctions are fast-paced, though, so make sure you set a budget and stick to it. Attend a sale first to learn the ropes before you decide to bid.

You’re likely to be bidding against experienced dealers, so be wary of getting carried away. Most importantly, all sales are final so make sure you inspect any cars you’re interested in before committing.

For more information, check out our expert guide on where to buy a car.

How to pay for a used car

The cheapest way to buy a used car is to pay cash upfront – by this we mean using actual cash (be careful if you’re carrying a large number of bank notes with you), a debit or credit card, or a bank transfer. It could also include money you’ve borrowed via a personal loan.

Whichever ‘cash’ method you choose, the seller gets paid straightaway. For that reason, be very careful you don't hand over the cash to a private seller, or make a bank transfer to them, without being sure you're going to get the car in return.

Buying from a dealer is much lower risk, and most offer finance packages where you can spread the cost of the car over several months or years. You can even take out a PCP agreement on a used car, though ensure you take a long look at the numbers to make sure you aren’t better off with a new car instead.

To find out more about the payment options available to you, head to car finance explained.

How to save money on a used car

Wherever you choose to buy your next used car, and however you intend to pay for it, there’s always scope to save money.

How to haggle for a used car

If you decide to buy privately after checking and test driving the car, it's time to negotiate a price. Look for things that could throw up costs in the near future - such as a short MOT or worn tyres - and use these as bargaining points.

We've got expert tips on haggling, including our tried-and-tested script. So make sure you read our guide on how to get the best price on a car.

Which type of car should I buy?

Models that are typically in demand, such as the Volkswagen Golf and BMW 3 Series, will tend to resist depreciation better. This means they will command a modest premium, compared to similar models on the used market.

So if you’re not interested in following the latest car fashions, or aren’t loyal to one particular brand, you could save money on your next used car. Choosing an unfashionable body type (an estate over an SUV, for instance), a less well-known manufacturer or an unpopular engine type could all help you bag a bargain.

One thing to be wary of is the lure of the cheap luxury car. They may be cheap to buy but pricey models from upmarket manufacturers suffer very heavy depreciation, and servicing and maintenance costs won't shrink over time. In fact, luxury models are the most expensive to keep on the road, and the most likely to give you problems as they age.

To find out which brands are the most, and least, reliable, go to most reliable car brands.

Get a used car valuation

Online car-valuation tools give an approximate valuation for any car you’re considering, putting you in a stronger position as a buyer. Most work by letting you enter a registration number and approximate mileage, but you can also often search by make, model and year.

Glass's, CAP and Auto Trader are three such providers of online valuation tools, but there are many others. Most valuation tools are free to use, but you'll normally have to provide some details to use them - such as signing up for an account or providing an email address.

What documents should I get when buying a used car?

When buying or selling a used car privately, it is your responsibility to ensure you’ve informed the DVLA of the change in its registered keeper. Traditionally, both parties signed the relevant section of the car’s V5 document (the car’s logbook), then posted it to the DVLA. After this, a new V5 document is issued in the new owner’s name.

To speed up the process, you can use the DVSA online service (available every day from 7am to 7pm) - it can be used by both buyers and sellers. Records are instantly updated and you’ll get a confirmation straightaway. The DVLA will also automatically cancel the seller's vehicle tax and any direct debits, then refund any full months remaining on the vehicle tax.

It is the buyer’s responsibility to ensure the car is re-taxed and that they have appropriate insurance before driving it away.

Our independent lab and road tests go beyond manufacturers' claims to reveal each model's real-world emissions and fuel economy, or range. Our annual survey of thousands upon thousands of drivers also uncovers the UK's most, and least, reliable cars. Don't buy a used car until you've read our car reviews


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