The technician will start the vehicle and turn on the air conditioning system, measuring the actual temperature at the vents at the lowest and highest settings with a thermometer; at the same time, they will connect a manifold pressure gauge to check if the refrigerant pressure in the high and low pressure lines is within the normal range, determining if there is a chronic refrigerant leak.

A clean title check has three layers. First, run the VIN through maintenance records: dealers in China log service visits with mileage, and gaps or mileage rollbacks are red flags. Second, pull insurance claim history — major accidents, fire and flood damage usually leave claim records even if the car was repaired well. Third, verify registration status: confirm the car is not under finance, court seizure, or theft report. From overseas, you can engage a local inspection agency or law firm to retrieve these records and issue a written report. Cross-check the VIN and engine number on the report against the registration certificate; any mismatch means walk away.

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.