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).

Almost all compliant models with hidden door handles have a mechanical emergency pull cable designed inside the car or under the vehicle. If the target country's climate is extreme, we will record a practical emergency door opening tutorial video for you before shipping.

The technician will put the vehicle in neutral on the lift, rotate the wheels, and listen for any abnormal metal gear whine from inside the motor reducer, and check for gear oil leaks at the joints of the reducer housing.