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).

International wire transfers generally follow "shared (SHA)" or "sender pays all (OUR)" principles. To ensure we receive the full remaining payment to release the bill of lading, we require all buyers to choose the "OUR" option when remitting, covering all intermediary bank fees.

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.