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).

Do not use a high-pressure water gun directly! The high-pressure water can instantly damage the fragile aluminum fins of the condenser, leading to a permanent decrease in cooling efficiency. We can only use a low-pressure air gun or a soft brush for surface cleaning.

If the buyer's country is under international sanctions, or if the buyer fails to provide a legitimate source of funds leading to the bank returning the payment, all transfer fees and exchange rate losses incurred during this period are to be borne entirely by the buyer.