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).

If there is a minor leak in the lines due to bumps, it is possible that the cooling may not work upon arrival. This is a normal physical loss. The cost of vacuuming, pressure testing, and recharging refrigerant at a local auto repair shop is low and is the buyer's responsibility.

Yes. We will use a professional diagnostic tool to scan all vehicle systems, including the Engine Control Unit (ECU), Transmission Control Module (TCM), Anti-lock Braking System (ABS), and Airbag Module (SRS), and provide English screenshots of all current and historical Diagnostic Trouble Codes (DTCs).