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).

Completely different. The assessment of commercial vehicles focuses on: the extent of wear/deformation in the cargo area, whether the frame has been twisted due to overload, the fatigue of the leaf springs, and the emissions of the diesel engine. Minor exterior scratches carry very little weight in the assessment of commercial vehicles.

Chinese passenger cars produced after 2005 have fully transitioned to asbestos-free brake pads, clutch plates, and gaskets. However, for export to countries with strict regulations, buyers must pay for sampling and testing by a NATA-accredited laboratory before shipment, and obtain an asbestos-free certificate.