How to Buy a Used Car

the essential checklist when buying a used car

How to Buy a Used Car

The key to a successful used car purchase is to be thorough. Know what you are looking for, stick to your guns and stick to your budget. A flash new drop-top with a throbbing V8 under the bonnet may seem like a good idea at the time, but the honeymoon will come to an end when the high petrol and insurance bills come in.

Equally, you don't want to end up with a rust bucket that you can never get started and costs more to get through the MoT than you paid for it in the first place.

Fret not, help is at hand! Avoiding the pitfalls is relatively easy as long as you are prepared to take a bit of extra care. Firstly, if you can help it, don't shop for a used car alone. You will probably need some moral support, as well as someone to keep your feet on the ground if you see a car you really like - when it's not their money, they can take on an impartial view. It's also important to have someone else to help you run through the following series of checks. If you know anyone in the motor trade themselves, of course you should rope them in.

Quick Checks

Before you even take the car out for a test drive, there are a few things that you should check...

The Body work

Accidental Damage

Check to see if the gaps between the body panels are even and that the doors don't drop on their hinges or fit badly. This is a quick way to tell if the car has been involved in a serious accident.


If the metal panels are not all the same colour, the car has had a partial re-spray, pointing to either covered-up rust or an accident. Run a magnet over suspect areas, if it's not attracted then body's full of filler. Inspect the sills (the metal rails between the bottom of the doors and the floor), the floor itself and the exhaust for rust. If you find corrosion here, it will fail it's MoT and on a cheap car it may not be economical to fix.


If there is one, check the sunroof to make sure the seal has not perished and that it opens and closes properly. Check the floor for damp, which often indicates a leaking sunroof, which in turn could be causing the floorpan to rust.


Bounce on each corner of the car. It should go down sharply when you put your weight on it, then return back to its original position in one movement, and settle. If the body takes a while to settle, then new shocks are needed. Check whether the shock absorbers are leaking fluid.


Check the switches work Check that lights, indicators, heaters and powered windows all work since electrical items can be expensive to fix. Don't be shy, press every button you can find! To be really sure, test combinations of equipment too: a wiring fault might mean that the indicators work perfectly on their own, but won't come on if the headlights are set to main beam.


If you are looking to buy a cheap car, then the cost of replacing tyres can make a large dent in your wallet. Make sure they have at least the legal minimum of tread, and that they are worn evenly.


Obviously if the odometer has been fiddled with and the car has done more miles than it says, it is worth less and could give you more trouble. It is usually easy to spot a 'clocked' car: the digits may not be properly aligned, or, more obviously, the screws holding the instruments look as if they have been tampered with. The most telling sign of all is the car's interior. The driver's seat and the foot pedals in particular will look more worn than you'd expect. Also, the steering wheel of a high mileage car will be worn smooth around the outside. Don't be conned - look for a full service history which will confirm the mileage, and prove the car has been cared for.


You should never rush through the paperwork - and the more there is, the better. What may look like rubbish, such as old receipts for work done, can actually be a good indication of the level of care the vehicle has received from previous owners. Of course you should also take the time to make sure the registration and VIN numbers on the documents match those on the car.

Check the Engine & Take it For a Test Drive:

Check the engineCheck Under the Bonnet

You should only test drive a car when the engine is cold - check to see if the car has been pre-warmed by the seller. If it has, he could be trying to hide an ignition problem from you. Check that there is plenty of fluid in the radiator, and that it contains antifreeze (it will be coloured bluish-green or pink instead of clear). If it doesn't, the car hasn't been maintained properly.

Ensure that the oil level is between the dipstick's maximum and minimum marks. Does the oil look clear, or is it a dirty thick sludge? Sludge could mean the car has been neglected - a bargaining tool in the absence of any engine problems, but also a warning sign that you should look out for mechanical faults due to wear. If the owner couldn't be bothered to change the oil, what else have they neglected?

A white creamy deposit on the inside of the oil filler cap is a sign that the head gasket has failed or coolant is making its way into the engine via a faulty seal. In either case, walk away as the engine could soon be on its way out. Watch out for rust in the engine bay, especially around the metal suspension turrets. It could result in an expensive MoT failure.

The Engine

Start her up. The colour of exhaust fumes is a good indicator of the engine's condition. Blue means it's burning oil, which could be expensive to fix. Black means the fuel to air ratio is too rich. White exhaust is normal on start-up, especially on a cold or damp day. This should disappear as the engine warms up; if not, inspect the head gasket and check for signs of coolant in the oil.

On the Test Drive

Take the car on a test driveClutch and Gearbox

With the engine running, push down then release the clutch pedal. A change in engine note indicates a worn bearing. Check that the gearstick moves smoothly from one ratio to the next, without any 'graunching' noises, and then pull away. Accelerate to top speed in a low gear then (when it's safe!) suddenly lift your foot off the throttle. Does the car jump out of gear? Stop and put the car into reverse. Does the gearbox resist? If so the selector mechanism could be damaged.


When you are out on your test drive (and preferably somewhere nice and quiet so that you don't cause an accident!) brake as firmly as you can without skidding. If you hear a metallic metallic grinding noise, then the brake pads or shoes are worn out. If the car swerves at all when you brake, then you need to do some investigating to find the cause.


Listen for noises that could spell trouble. Abnormal engine sounds are the worst. A clattering noise when the engine is cold is bad news for a petrol car, though it's normal for diesels.

Any banging means it's on its last legs, while a deep 'wuffle' from the exhaust means there's a hole in it. If you're driving uphill and the pitch of the engine note starts to rise without the car going any faster, the clutch is slipping and needs replacement. If the steering wanders, or you can hear knocking noises driving over bumps, part of the system may be working loose.

Take a Time Out

Once you've made all your checks and taken the car out for a spin, it is wise to take a step back and think about whether or not you want to make an offer without the salesman looming over you. Go for a coffee, take a stroll down the road or look at a few other dealers before making your decision.

If you decide to go for it, haggle for a good price to make sure you get the best deal. Whoever you are buying from, the rules of haggling are the same: be polite and thorough, but be firm!

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