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).

We maintain an absolute skeptical attitude. In addition to regular visual inspections, we focus on checking for sediment accumulation around the sunroof drainage channels and look for water stains under the A-pillar trim and front floor mats. This is the only effective physical evidence to determine if the sunroof drainage holes are blocked, leading to hidden leaks.

It depends on the specific brand and model. Some brands (like BYD and MG) have native multilingual systems that can switch to English directly; however, some models designed for the Chinese domestic market only have a Chinese interface. For systems that only have Chinese, we can assist with compliant system flashing (installing international firmware) or adding modules that support Apple CarPlay/Android Auto, so you can use Google Maps. The details page will clearly indicate the language status of each vehicle's system.