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).

Experience turbo lag and power surge during road tests; check for significant oil accumulation at the turbo intake and intercooler connections (slight oil vapor is normal); and use OBD to read the real-time boost pressure peak to see if it meets factory settings.

It's not mandatory. Four-wheel alignment and dynamic balance are part of routine maintenance. During long-distance towing and sea transport, the suspension may experience slight changes in stress. We recommend that buyers perform a four-wheel alignment locally after picking up the vehicle at the destination port and replacing tires suitable for local road conditions.