How to inspect a used car

1. Before you go

• Run a history check. A paid check tells you whether there's outstanding finance on the car, whether it's been written off by an insurer, and whether it's recorded as stolen.
• Read the MOT history. It's free on GOV.UK with just the registration. Look at the mileage at each test, and at the advisories. The same advisory coming back year after year shows what's been put off.
• Ask the seller a few questions. How long they've owned it, what work has been done recently, whether it has a service history with invoices, and how much oil it uses between services.
• Ask for the car to be cold when you arrive. Some faults only show in the first minute after a cold start. Arrange to view in daylight, ideally when it's dry, as water hides paintwork faults.
• Take a torch and a clean cloth. The torch is for underneath, behind the wheels and under the bonnet; the cloth is for the dipstick and the tailpipes.

2. The walkaround, engine off

• Before anything else, put a hand on the bonnet. If it's warm, the engine has been run before you arrived.
• Bodywork. Look along each side in good light for ripples, colour differences between panels and uneven gaps. Paint on rubber seals or trim is a sign of a respray.
• Underneath. With the torch, look for fresh oil or coolant drips, and for corrosion on the sills, jacking points and suspension parts.
• Tyres and brakes. Matching tyres from a known brand, worn evenly across the tread, suggest a car that's been looked after. Wear on one edge can mean the alignment is out. Look at the brake discs through the wheels for a deep lip at the outer edge.
• Under the bonnet. Check the oil level on the dipstick or the dashboard, and that the coolant is at the mark and clean. A little creamy residue under the oil filler cap can come from short journeys; a lot of it, or oily coolant, needs explaining.
• Inside. Wear on the seat, steering wheel and pedals should match the mileage. Smell for damp, feel the carpets, and try every switch, window and the air conditioning.

3. The cold start

• Turn the ignition on before starting. Every warning lamp should light, then go out once the engine runs. A lamp that never lights may have been disabled.
• Listen for the first minute. Rattles, ticks or knocks that carry on once the engine has settled are worth noting, as is an idle that hunts up and down.
• Watch the exhaust. A little vapour on a cold day is normal. Blue smoke points to oil being burned, steady white smoke that doesn't clear can mean coolant, and black smoke means the engine is running rich.

4. The drive

• Drive it on different roads, including a faster stretch, for at least 20 minutes so it reaches full temperature.
• Clutch and gears. A clutch that bites very high or slips under acceleration is near the end of its life. Gears should go in cleanly. An automatic should change smoothly, without flaring or thumping.
• Brakes and steering. Under firm braking the car should stop straight, without judder through the pedal or wheel. On a straight, level road it shouldn't pull to one side.
• Suspension. Listen for knocks over bumps and feel for the car floating or wallowing.
• Afterwards, check the temperature gauge sat in the middle, then look underneath again for anything new.

5. The paperwork

• The V5C logbook. The name and address should match the seller, and the VIN on the V5C should match the car (usually at the base of the windscreen and on a door pillar).
• The service history. Stamps are good; invoices are better, because they show what was actually done. Look for the big model-specific jobs, such as a cambelt, at the right intervals.
• Keys. Count them. Replacement keys for many modern cars have to be ordered and coded.

Why the model matters

Everything above applies to any car. What makes the difference at a viewing is knowing what to look for on the one in front of you, because cars that look alike can be built very differently. A few examples:

• On a Porsche 911 997.1, wiping both tailpipes before a cold start and comparing them is one of the signs of cylinder bore scoring, which a borescope inspection then confirms or rules out.
• On a BMW 1 Series E87, the water pump is driven by the accessory belt on some engines and is electric on others, so what to check, and what it means, depends on which engine you're looking at.
• On an Audi Q3 8U, the air conditioning compressor has no clutch, and a failed control valve is the most common fault. A quote for a whole compressor without that valve being checked may be for more work than the car needs.

Browse buying guides by model for the main checks on each generation.

Do you need a professional inspection?

For an expensive car, or one you have doubts about, a mechanic's inspection is money well spent. Doing a thorough inspection yourself first helps you choose which car is worth paying for, and avoids paying to inspect one you could have ruled out at the viewing.