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).

Supply and demand determine prices. In the Chinese market, mainstream colors like black and white have much higher resale values and market circulation speeds compared to less popular colors (like pink or bright green). Therefore, there is a price difference of thousands of RMB for specific colors at the procurement level.

No hidden fees. The total amount on the FOB/CIF invoice is the final amount. We rely on professional supply chain operations to earn a reasonable margin and do not allow any sales personnel to privately request kickbacks or service fees from you.