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).

Under international practices and our standard CIF/FOB terms, the THC at the port of origin (China) is borne by the seller; all THC and port miscellaneous charges incurred at the destination port during unloading are to be paid by the buyer (consignee) upon local customs clearance and pickup.

We will remove the chassis guard to physically inspect the battery pack's lower shell for serious dents or scratches, and check for signs of mud or sand intrusion in the waterproof vent at the edge of the battery pack.