We can only infer from the existing connected maintenance records. If the records show continuity and adhere to the recommended maintenance schedule, we will assign a high credit score; if there are gaps of tens of thousands of kilometers, we will assume it was not well maintained during that period and alert you.

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).

4S dealership records are directly connected to the manufacturer's database, making the data hard to tamper with and the most reliable, with original parts guaranteed; third-party repair shops usually are not connected, making their data unverifiable. Therefore, we only consider the connected records from 4S dealerships as valid historical documentation.