How do I know if a used car has problems?

Use a 4-step check: history report, your own inspection, test drive, then a pre-purchase inspection (PPI).

1) Check the history
Look up the VIN on Carfax or AutoCheck. Red flags: salvage/rebuilt/flood title, accident or airbag deployment, odometer mismatch, spotty service records.

2) Inspect it parked
Check for mismatched paint, uneven panel gaps, rust bubbles, fluid leaks, uneven tire wear, milky oil, burnt-smelling transmission fluid, and make sure all windows, lights, buttons, and warning lights work normally.

3) Test drive it
Start it cold if possible. Listen for rattles, squeals, smoke, pulling to one side, hard shifting, slipping, jerking, vibration when braking, or grinding/squealing brakes.

4) Pay for a PPI
An independent mechanic can spot frame damage, suspension issues, leaks, and stored trouble codes you might miss.

Best rule: one warning sign isn’t always a dealbreaker, but several together usually mean walk away.