How to Inspect a Used Car Before You Buy

On a sunny day, stand at each corner of the car and look down the body panels from a low angle. Waves, ripples, or color mismatches in the paint indicate prior bodywork or panel replacement from an accident. Check for overspray on rubber trim and window gaskets — a sign of repainting. Look for gaps in body panels that aren't symmetrical from side to side, which suggests frame damage or poor repair work. Check all glass for chips, cracks, and replacement windows (a non-factory windshield or glass is often visible from an angle due to different tint). Examine the tires for even tread wear — uneven wear indicates alignment or suspension issues. Look under the car in the front and rear for fresh undercoating (spray-painted undercarriage) that can hide rust.

Check all fluid levels: engine oil (color and level — very dark or low oil indicates deferred maintenance), coolant (the overflow reservoir level and the color — should be bright, not rusty or milky), power steering fluid, brake fluid, and transmission fluid if accessible. A milky engine oil or coolant can indicate a blown head gasket — a very expensive repair. Look for oil leaks on the top of the engine and the ground under the car where it was parked. Check belts and hoses for cracking and fraying. Examine the battery terminals for corrosion. On newer cars, look for any recently replaced components — fresh bolts or unpainted metal indicate recent work in that area.

The test drive reveals what static inspection cannot. Drive at highway speeds (60+ mph) if possible — listen for wind noise, vibration, and pulls in the steering wheel at speed. Brake firmly from 50 mph in a safe area — the car should stop in a straight line without pulling. Listen for grinding or squealing that indicates brake wear. Test the heating and AC by running both at maximum settings — they should both respond quickly and effectively. Drive over a rough surface and listen for clunks, rattles, and squeaks from the suspension. Shift through all transmission gears and verify smooth engagement. Park on a level surface and verify the car sits level side-to-side.

Any auto parts store will read OBD fault codes for free, and an inexpensive OBD2 scanner ($25–$50) is a worthwhile investment if you buy used cars regularly. Plug the scanner into the OBD port (usually under the dashboard, driver's side) and check for stored and pending fault codes. Some sellers clear fault codes before sale — the scanner will show 'monitors not ready' if this was done recently, which is itself a red flag. Emissions test failure codes, transmission codes, and ABS/brake system codes are significant concerns. An independent mechanic's pre-purchase inspection for $100–$150 takes the diagnostic scan further — they check components the OBD system doesn't monitor, including suspension, brakes, and rust.