This list is by no means exhaustive and should not take the place of expert advice. A good place to start is by searching the internet for common faults with the vehicle you are looking to buy. As well as this, we recommend taking a friend who knows about cars with you to view the car before you buy it, or you could buy a mechanical check from a company such as the AA.
Wheel balance alignment
- Check that all four tyres are evenly worn.
- Look for any damage to the tyres such as cuts or bulges.
- Have a look at the alloys/rims for any damage.
- Tyres must have at least 1.6mm of tread across the central three quarters of the tyre all the way around the circumference to be legal.
- Tyres with less than 3mm of tread will need to be replaced soon, so you should take this into consideration when negotiating price.
- A red ignition warning light and a rapid increase in engine temperature could mean the alternator belt is broken.
- If the car is having battery problems or dim headlights when the car is not moving this could also be a sign that there’s something wrong with the alternator.
- Without the battery being in a good condition, or with a flat battery, the car won’t start.
- Make sure that the battery is secure and that the terminals are tight.
- If the battery charge warning light doesn’t light up at all (it should come on when you turn the key in the ignition, but then go out once the engine’s running) or if it lights up while you’re test driving the car this indicates a problem with the charging system.
- Take a look at the battery. If there’s green fuzzy stuff around the terminals this could be a sign of corrosion. Corroded battery terminals can cause problems, so if the car doesn’t start first time this could be the issue. However it’s usually an easy fix so it's not generally something to worry about.
- Refer to the car’s maintenance manual when looking at issues with the battery.
- Fully functioning brakes are obviously essential - they could mean the difference between life and death.
- Test the brakes on your test drive. If the pedal feels spongy or like you need to press it all the way to the floor before the car slows down, this should be a red flag.
- The car shouldn’t pull in either direction or judder when you’re braking heavily, but some vibration in the brake pedal is normal if you brake sharply and the ABS kicks in.
- Juddering or noisy brakes may be an indication of worn or damaged parts that need to be replaced.
- If the car pulls to one side when you brake this could indicate poorly adjusted brakes.
- When test driving the car, apply the brake pad gently to see if it pulses or if the car slows down unevenly - this could indicate badly worn brake discs.
- A brake warning light on the dash might also indicate a system fault, so watch out for this.
- The ABS warning light should illuminate on starting the engine and then go out after a few seconds. If it stays on, this will indicate a problem with the ABS and means the car will fail a subsequent MOT.
- Check that the car you're looking at has ABS. If the lamp fails to illuminate, this could also be a problem and will be an expensive repair.
- Check that the handbrake, when applied, holds the car in place and also look out for any excessive travel when it is applied.
- Some cars don’t have a cam belt but have a chain instead - these often last the lifetime of the car.
- The cam belt should be replaced in accordance with the manufacturer’s guidelines. It’s usually listed in both miles and time (whichever occurs soonest).
- If the cam belt hasn’t been changed, it shouldn’t necessarily stop you from buying the car but you should take it into consideration when negotiating the price as it’s something you might need to have replaced immediately.
- If the cam belt breaks it can cause considerable damage to numerous engine parts and can mean a whole new engine is on the cards.
- Look for documented evidence that the cam belt has been changed, as per the schedule.
- You should check the engine coolant is at the correct indicated level when the engine is cool.
- As cars age they can start to leak coolant, and it’s vital that it's kept topped up to prevent the car’s engine from overheating and potentially destroying it.
- Check the water level only when the engine is cold, and make sure that there are no contaminants in the coolant. It should be a coloured liquid with no sludge or evidence of oil contamination.
- If the car makes different noises when you push down the clutch pedal or put the car into gear, this could mean that there’s a problem with the clutch.
- You should be able to feel the biting point of the clutch around half way up the clutch pedal’s travel. If it releases near the top, doesn’t engage until the very bottom, or feels abnormally soft or heavy then a new clutch might be needed soon.
- These can be expensive to replace so you’ll want to take this into consideration when deciding whether or not to buy the car.
- There is usually more than one fuel filter in all cars - so check all of them when buying a vehicle.
- The fuel filter should be changed at regular intervals, and you should find the service schedule in the car’s manual.
- In some cars, the fuel filter has been removed from the servicing schedule because it’s inside the fuel tank.
- When test driving the car, if it struggles when going uphill or accelerating, this could be due to a clogged up fuel filter.
- Spark plugs are fitted on petrol cars. They’re a fundamental part of the engine and need to be replaced regularly.
- Check the service history of the car to make sure it’s been serviced regularly. The service interval guide in the handbook should tell you how often the spark plugs need to be changed.
- Worn spark plugs can cause a range of problems including poor acceleration and increased fuel consumption.
- While driving, if the steering doesn’t feel very responsive and you can turn the wheel a few degrees without anything happening this could indicate worn suspension and steering parts.
- The steering should also feel the same whether you’re going round a left or right-hand corner. If not, this could suggest issues with the suspension or accident damage.
- If the ride is a bit shaky and you can hear knocking noises when going over bumps, this could mean parts of the suspension are worn and need replacing.
- When you start the engine, take a look at the exhaust and look out for smoke. Steam or a small amount of white smoke coming from the exhaust when you start the car is normally perfectly fine. On a cold or humid day you might expect to see a little more. The warning signs are blue, excessive white or black smoke.
- You should also check in the rear-view mirror for smoke when you’re accelerating, in case there’s an internal oil leak, head gasket failure, problems with the turbo or a poorly tuned engine. Any of these things will need work and could hit your pocket hard.
- When the engine is warm, have someone rev the engine and look at the exhaust gases coming out rear of the car. The gases should be neutral; any excess of colour as previously described could indicate problems with the engine.
- Also check for leaks in the exhaust - listen for hissing sound along the length of the exhaust.
- During the test drive, listen out for a louder than normal exhaust noise and rattles. A particularly noisy exhaust could be a sign of a hole, which may be repairable but could also mean you need a whole new exhaust.
- Rattling may simply be caused by a worn bracket – these are generally cheap and easy to replace.
- If the car doesn’t start, there could be a problem with the starter motor.
- If there’s a loud high-pitched noise when you start the engine this could also suggest a faulty starter motor.
- When going to look at a car, it’s important that the owner hasn’t started it before you arrive as they might have needed to jump-start it.
- You should also try to start the car when the engine’s cold to make sure the car starts in all conditions.
- If there is air conditioning in the vehicle, check that it works. If not, it could be anything from a simple re-gas or a very expensive repair.
Buttons and switches
- There are loads of buttons and switches within a vehicle and when purchasing a second hand car, it is important to check that they all work. These can be anything from switches for electric windows, indicators and wipers to the radio/cd player buttons.