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).

It usually refers to very small stone chips on the hood from high-speed driving, nail scratches on the inside of door handles, slight curb scratches on the edges of wheels, and minor wear on interior plastic parts. These do not affect the vehicle's functionality or corrosion resistance.

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.