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.

Europe and some developed countries have very strict regulations on greenhouse gases. If required by customs, we will specify the exact refrigerant type and charge amount according to the vehicle's air conditioning compressor nameplate in the remarks section of the packing list and commercial invoice.