We conduct basic visual inspections and freezing point tests. If the antifreeze's freezing point is insufficient or the engine oil is severely degraded, we will document it. However, considering the shipping duration, we strongly recommend a comprehensive "Full Fluid Service" upon arrival.

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).

Once the car system (especially in a closed ecosystem) undergoes a major version upgrade, its bootloader is usually locked, preventing downgrades. If this happens, there is basically no solution in an overseas environment. Therefore, we strongly warn: do not blindly insert a USB drive to upgrade while offline.