Maintain objective expectations. Vehicles over 5 years old inevitably show signs of decreased paint gloss, slight aging of rubber seals, irreversible patina on interiors, and surface rust on chassis components. As long as core structure and mechanical failures are not involved, these are normal depreciation characteristics over time.

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.