How to check a used car before you buy it
Most problems with a used car can be found without tools, if you know where to look and do it in the right order. This is the order Credov's inspectors walk a car.
It matters: in New Zealand, 22% of people who bought a car from a private seller had a problem with it, and the average fix cost $11,762 (NZ Consumer Survey 2024).
1. Before you go
- Look up the car's history and money owing with the plate or VIN: CarJam or MotorWeb in New Zealand, a PPSR search in Australia.
- Look up the known faults for the exact model, year and engine. Every model has its weak spots: see common problems by model.
- Ask the seller not to start the car before you arrive. A cold start tells you the most.
2. Outside the car
- Walk round it in daylight. Look along each side for ripples, mismatched paint and uneven panel gaps, which point to past repairs.
- Tyres: tread depth, uneven wear (a sign of alignment or suspension trouble), cracks and the date code.
- Glass: chips and cracks in the windscreen, especially in the driver's view.
- Lights: headlights, indicators, brake lights and the number plate light.
- Look through the wheels at the brake discs: a deep lip on the edge means they are worn.
3. Inside the car
- Turn the key to on without starting: every warning light should come on, then go out once it starts. A light that never comes on may have been disabled.
- Seats, belts and buckles, windows, locks, mirrors, the air con (cold within a minute) and the heater.
- Smell for damp or mould, and lift the boot floor to look for water.
- Compare wear on the pedals and steering wheel with the odometer.
4. Under the bonnet
- With the engine cold, check the oil level and colour, the coolant level and colour, and look for leaks and wet patches.
- Check the belts for cracks, and the battery for corrosion.
- Then start it cold. Listen for rattles in the first seconds (a timing chain), knocking, and look for smoke from the exhaust.
5. Underneath
Lie beside the car with your phone torch. Look for oil and coolant drips, rust on the chassis rails and sills, a rusty or patched exhaust, and split rubber boots on the driveshafts.
6. The test drive
- At least 15 minutes, including a motorway or open road if you can.
- Gearbox: smooth shifts, no slipping, no flare or clunk. A manual's clutch should bite in the middle, not at the top.
- Brakes: straight and firm with no shudder. Steering: no pull, no knocks over bumps.
- Listen for humming that rises with speed (a wheel bearing) and whine from the gearbox or diff.
7. After the drive: codes and leaks
With the engine hot, look underneath and under the bonnet again for new leaks, and check for smoke. Then plug in a cheap OBD2 scanner and read the stored codes. Photograph them before you clear them. See using an OBD2 scanner.
8. The paperwork
Service history (receipts, not just stamps), when the timing belt was done if it has one, the WoF or roadworthy, and that the VIN on the car matches the papers.
Price what you find
A fault isn't a reason to walk away; an unpriced one is. Look up what it costs to fix in repair costs and take it off your offer.
Questions
How long does a used car check take?
About 30–45 minutes for a careful check without tools, including a 15-minute test drive.
What is the most important thing to check on a used car?
Start the engine cold and watch the warning lights at key-on. A cold start shows rattles, smoke and starting problems that disappear once the engine is warm, and the warning lights show faults the car has already found.