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).

We use an internationally certified electronic signature platform (such as DocuSign or Adobe Sign). Each signed contract generates a digital certificate with a timestamp and encrypted hash value, which has full legal defense effectiveness in international arbitration courts.

Yes. If your country (such as Chile, Peru, ASEAN countries, etc.) has signed a bilateral free trade agreement with China, our documentation center will apply to Chinese customs or the trade promotion agency for specific versions of the certificate of origin (such as Form E, Form F, etc.), which can help you legally apply for significant tariff reductions at the destination port.