Mercedes C180

Check 48V Mild-Hybrid (EQ Boost) System operation | Description: Verify the EQ Boost power-assist and energy recovery engage smoothly on the dash. Any hesitation, jerky auto start-stop, or warning lights indicate potentially catastrophic 48V battery or integrated starter-generator (ISG) failure, which is a notorious and expensive issue for facelift W205 models.

Inspect 9G-TRONIC transmission behavior during low-speed shifts | Description: Ensure gear changes are seamless, especially when cold. Harsh shifting, hesitation, or unexpected shuddering during low-speed traffic acceleration are common signs of early valve body wear or the need for a critical TCU software re-adaptation.

Inspect engine bay for coolant housing and water pump leaks | Description: Check for white residue or weeping around the plastic coolant thermostat housing and the water pump assembly. The M264 engine utilizes complex thermal management components that are known to become brittle and leak prematurely.

Listen for brief timing chain rattle upon cold startup | Description: Perform a strict cold start with the windows down and listen for a brief metallic clatter from the front of the engine. While less prevalent than on older engines, chain stretch or tensioner leak-down still occurs and requires immediate attention to avoid skipped timing.