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).

We will provide the transfer record from the vehicle registration certificate. A high number of transfers does not necessarily indicate poor condition (for example, internal transfers within a family for quota purposes), but we will consider it a risk factor and conduct a more thorough physical inspection to verify its actual condition.

We will directly check the registration certificate (the big green book) and count the number of changes.