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.

Under normal circumstances, it takes 15 to 25 working days. This includes: domestic transfer of ownership (3-5 days), applying for an export license (3-5 days), inland trucking to the port (2-5 days), customs inspection and waiting for loading schedule (5-10 days). Do not trust false promises from other channels claiming 'loading within a week.'