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).

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.

Most leading Chinese brands' car systems support "offline voice commands" (like adjusting temperature and opening windows). However, if recognition fails due to accent or language limitations (only standard Chinese is supported), you can always control it via the physical screen.