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).

The customs of the destination country has the right to disregard the commercial invoice and reassess the value based on its internal database (such as the customs valuation red book). Any additional duties incurred are a result of the importing country's policy and are fully borne by the buyer (importer).

To prevent intermittent failures due to aging of the resistance wire, we will start the engine and set the seat heating/ventilation to maximum for at least 5 minutes, confirming significant temperature changes or airflow output in the cushion and backrest using an infrared thermometer or body sensor.