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).

Changes must be requested before the shipping cut-off date (SI Cut-off Date) prior to the vessel's departure. Once the vessel has sailed, the shipping company will charge a high amendment fee, which may also cause delays in customs clearance at the destination port, with costs borne by the buyer.

Most leading Chinese brands' car systems support "offline voice commands" (like adjusting temperature and opening windows). However, if recognition fails due to accent or language limitations (only standard Chinese is supported), you can always control it via the physical screen.