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 cannot open each tire to inspect the inside. However, if a visual inspection reveals severe creases on the tire sidewall, it indicates that the run-flat tire has been driven for a long time at zero pressure, damaging its internal structure. We would recommend replacing it before shipping.

During the stationary steering test, the technician will check the smoothness of the steering wheel from full left to full right, looking for any unusual noises from the steering gear; they will also inspect the hydraulic power steering pump (if present) and the seals of the steering column for any hydraulic fluid leakage.