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).

For dealers who purchase the same brand models in bulk over a long term, we can coordinate senior technicians domestically to offer paid, regular Zoom video technical Q&A to resolve the issues you encounter locally.

If the system reports "storage card error," we will consider it as damage or loss of the original owner's personal items, and the platform will not provide a new high-speed TF card for free; the buyer must purchase a replacement after arriving at the port.