Rust is one of the most underestimated problems in remote buying. Request specific evidence: photos of the underbody, wheel arches, door sills, and around the windshield seal; close-ups of suspension mounting points; and ideally paint thickness readings across panels (factory paint is typically 80-120μm; heavy patches suggest bodywork). Northern Chinese cars may have winter road-salt corrosion; coastal cars can show surface rust on exposed metal. Surface rust on exhaust and bolts is normal—structural rust on frame rails, subframes, or brake lines is a deal-breaker, especially if the car is headed to a humid or coastal market. Have the inspector tap suspicious areas during the video call: flaky or bubbling metal sounds hollow. Walk away if the seller refuses underbody photos.

For gasoline cars, insist on a compression test: each cylinder should read within 10-15% of the others, and the actual values should match factory specs for that engine. A single low cylinder points to worn rings or valve problems that idle checks will never reveal. A leak-down test goes further. It pressurizes each cylinder and measures how much air escapes and where. Air hissing from the oil filler cap means ring wear; from the intake or exhaust means valve issues; bubbles in the radiator coolant mean a head gasket problem. This is the single most revealing test for engine condition. Also request OBD scan data with freeze-frame records, a coolant system pressure test (to catch hidden leaks), and an inspection of the timing belt or chain condition with service history. For electric vehicles, compression tests don't apply — instead ask for a battery health report from the BMS, motor insulation readings, and a road test logging any inverter or drive-unit fault codes. A written report with photos or video of each test is essential evidence for your records.

We cannot open each tire to inspect the inside. However, if a visual inspection reveals severe creases on the tire sidewall, it indicates that the run-flat tire has been driven for a long time at zero pressure, damaging its internal structure. We would recommend replacing it before shipping.