Mercedes-Benz C-Class W204 — Reliability
Reliability Summary
Engine
M274 — 69/100
ACCEPTABLE
Known Issues
6
Engine in this model
Known Issues Across All Engines
| Issue | Engine | Severity |
|---|---|---|
| Camshaft weld failure — camshaft can break (2015 builds, recall) | M274 | high |
| Camshaft-adjuster magnet valves leak oil into the wiring harness | M274 | moderate |
| Timing chain stretch / tensioner wear | M274 | moderate |
| Thermostat failure | M274 | moderate |
| Cold knock from the crank assembly — piston wrist-pin tolerance (built before April 2015) | M274 | minor |
| NOx sensor failure | M274 | minor |