Buying a used car can save you thousands compared to purchasing new, but it comes with risks. Hidden mechanical problems, outstanding finance, and clocked mileage are just some of the traps that catch unprepared buyers every year.
This guide walks you through everything you should check before handing over your money.
What Should You Research Online Before Viewing a Used Car?
Vehicle History Check
Before arranging a viewing, run a vehicle history check using the registration number. This will reveal:
- Whether the car has been reported stolen
- Outstanding finance agreements
- Previous write-off or insurance claims
- Mileage discrepancy alerts
- Number of previous owners
- MOT history (available free on the DVLA website)
MOT History
The UK government’s free MOT history tool shows every MOT test result, including advisories and failure points. Look for recurring issues — if the same problem appears year after year, it suggests the owner is not maintaining the car properly.
Also check that the recorded mileage increases consistently between MOTs. Sudden drops in mileage are a strong indicator of clocking.
What Should You Physically Inspect on a Used Car?
Exterior
Walk around the car and look for:
- Panel gaps: Uneven gaps between body panels suggest previous accident damage and poor repair work.
- Paint mismatches: Look at the car from different angles. Resprayed panels often have a slightly different shade or texture.
- Rust: Check wheel arches, sills, door bottoms, and around the windscreen. Surface rust is cosmetic; structural rust is a deal-breaker.
- Tyre wear: Uneven wear across the tyre indicates alignment or suspension problems. Check all four tyres, including the spare.
Interior
- Wear consistency: Does the wear on the seats, steering wheel, and pedals match the claimed mileage? A car with 30,000 miles should not have a worn-through driver’s seat.
- Electronics: Test every button, switch, and screen. Power windows, air conditioning, infotainment system, heated seats — everything.
- Smell: A musty or damp smell suggests water leaks. Lift the carpets in the boot and footwells to check for moisture.
Under the Bonnet
- Oil level and condition: Pull the dipstick. The oil should be between the min and max marks and should not look thick, black, or contain metal flecks.
- Coolant: Check the expansion tank. The coolant should be clean — brown or oily coolant suggests a head gasket problem.
- Belts and hoses: Look for cracks, fraying, or perishing on visible belts and hoses.
- Leaks: Look underneath the car for any signs of fluid leaks.
What Should You Check During a Used Car Test Drive?
Cold Start
Always try to see the car from a cold start. Sellers who have the engine running when you arrive may be hiding starting problems, excessive smoke, or unusual noises.
What to Listen For
- Knocking or tapping from the engine
- Whining from the gearbox or differential
- Grinding when braking
- Clunking over bumps (worn suspension)
What to Feel
- Vibration through the steering wheel (wheel balance or warped brake discs)
- Pulling to one side under braking (brake or alignment issue)
- Smooth gear changes (both manual and automatic)
- Clutch bite point (a very high bite point suggests a worn clutch)
Why Should You Run an OBD2 Diagnostic Check Before Buying?
This is the step most buyers skip — and it is arguably the most important one. An OBD2 scan reveals hidden fault codes that may not have triggered a warning light yet.
Bring a smartphone with Cars Guru installed and an OBD2 Bluetooth adapter. Plug it into the car’s diagnostic port and run a full scan. The app will show you any stored or pending fault codes and explain what each one means.
Pay special attention to:
- Cleared codes: If the system shows zero codes but the car has significant mileage, the codes may have been recently cleared to hide problems. Check the readiness monitors — if they show “not ready,” the codes were likely cleared just before your visit.
- Pending codes: These are problems detected by the ECU that have not yet triggered a warning light. They indicate emerging issues.
How Do You Negotiate the Price on a Used Car?
Armed with your inspection findings, you are in a strong position to negotiate:
- Use any faults or upcoming maintenance needs to justify a lower price
- Factor in the cost of fresh tyres, a service, or any repairs needed
- Check similar cars on AutoTrader and similar platforms to understand the market value
- Never feel pressured to decide on the spot — a genuine seller will give you time to think
What Should You Do After Buying a Used Car?
Once you have bought your car, the first thing you should do is set up a maintenance schedule. Cars Guru lets you add your new vehicle, log its current mileage and condition, and set reminders for all upcoming services. Start building a digital service history from day one — it will pay dividends when you eventually sell.
Download Cars Guru and give your used car the organised, well-documented ownership it deserves.