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).

If your remitting bank requires verification of the transaction's authenticity, we will promptly provide: a commercial invoice (PI) signed and stamped by both parties, a scanned copy of the vehicle purchase contract, and our legal export enterprise registration certificate from the Ministry of Commerce in China.

All our measuring instruments (especially calipers, paint thickness gauges, and refrigerant pressure gauges) are calibrated quarterly according to ISO quality management system requirements to ensure the data we provide you is objective, accurate, and reliable.