We use two steps: 1. Insert a medical-grade endoscope through the spark plug hole to visually inspect cylinder wall scratches and carbon buildup on the piston top; 2. Extract an engine oil sample to check for large metal debris or emulsification (caused by coolant leakage).

The catalytic converter contains precious metals, making it a target for theft. During chassis inspection, we check if the welding points of the catalytic converter are in their original state. Once verified, the vehicle will be sealed after being handed over to port logistics to prevent disassembly and resale.

Test-drive cars experience much more mechanical wear due to extreme conditions like cold starts and emergency braking compared to regular family cars. We can identify this by tracing whether the first owner was a 4S dealership or the manufacturer. If so, we will reassess its value based on "operational intensity" standards.