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 cannot privately forge or re-stamp the original vehicle nameplate (this is illegal). If the nameplate is unclear, we will rely on the clear VIN on the windshield and the engine stamp as supplementary proof, and we will warn you of this risk before shipping.

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.