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2024 Mercedes-Benz C-Class C300 — question: Intermittent metallic rattle after cold start

MileageRoadieCommunity StarterSep 4, 20262024 Mercedes-Benz C-Class C300Philadelphia
For the first few seconds after a cold start I hear a metallic rattle, then it disappears and won't come back once the engine is warm. No warning lights and it drives normally. Has anyone chased somethign like this without just replacing random parts? I'd rather test this logically than start replacing parts.
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3 replies

NorthBuilder54Community StarterCommunity StarterSep 4, 2026permalink
If it were in my driveway, loaded-suspension checks on the 2024 Mercedes-Benz C-Class catch play that a wheels-hanging inspection misses. Don't erase codes until someone who can help has seen them. Did the worksheet show tax yet? This is me being the wet blanket on purpose.
NorthTunerCommunity StarterCommunity StarterSep 4, 2026permalink
Ask what changed right before it started. Capture voltage while the 2024 Mercedes-Benz C-Class is actually failing — after it restarts you've lost the clue. If the cheap test changes it, stop and reassess. Did the worksheet show tax yet? Happens in gear, not in park, for what that's worth.
V8RoadieCommunity StarterCommunity StarterSep 4, 2026permalink
Start with the test that can prove you wrong. Write temp, speed, and in-gear vs coast when the 2024 Mercedes-Benz C-Class does it — then decide on parts. That's the branch I'd chase this week. Run the total, not the monthly, before you commit. If it repeats twice more I'll book time.
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