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.

This is a typical case of "secondary damage caused by unprofessional rescue." Many hybrid vehicles require access to "maintenance mode" via engineering computers to allow the water pump to run at full speed for exhaust. We do not bear any moral or financial responsibility for cylinder damage caused by local technicians' misoperation.