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.

If the delays are due to policy-related force majeure like customs system upgrades, or if our documentation errors lead to short shipments, all additional demurrage and storage fees incurred at ports within China will be borne by sellwellauto, and the buyer will not have to pay a cent.

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).