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).

As rubber seals age, "slight oil seepage (oil stains but no dripping)" is very common in used cars and is not considered a major fault. Our recommendation is: as long as the oil level does not drop abnormally, just clean and monitor it regularly after arrival, without the need to immediately incur high costs to disassemble and replace the seals.

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.