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).

Yes. For bulk purchases, we can organize and package the core historical records (transfer records, maintenance summaries) for each vehicle. If an English version is needed, we can provide a basic machine translation reference, and human translation assistance for key technical terms.

For dealers who purchase the same brand models in bulk over a long term, we can coordinate senior technicians domestically to offer paid, regular Zoom video technical Q&A to resolve the issues you encounter locally.