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).

No hidden fees. The total amount on the FOB/CIF invoice is the final amount. We rely on professional supply chain operations to earn a reasonable margin and do not allow any sales personnel to privately request kickbacks or service fees from you.

Testing is mandatory. Troubleshooting electrical devices in the car is part of the standard procedure. We will test the window lift motors, mirror folding, air conditioning compressor and fan, electric seat tracks, etc. Any stuttering or failure of electronic components will be recorded.