Why does my Mercedes-Benz make a clattering sound during cold starts?

Steve Mowat

Steve Mowat

Steve Mowat, Owner of Avantgarde Automotive, began as a BMW apprentice in 1997, then excelled at McLaren and Mercedes-Benz. In 2009, he founded his business.

Unearthing the Causes of Clattering Noise

Those early morning cold starts may introduce you to an unusual clattering sound from your Mercedes-Benz, particularly for models manufactured within the last 10 years. Here’s what could be behind that mysterious noise:

  • Hydraulic Tappets Malfunction: Models like the C-Class (W205) may have tappet issues, which can cause this noise.
  • Engine Oil Viscosity: In some Mercedes-Benz E-Class (W212), the engine oil viscosity may not be suitable for colder temperatures.
  • Timing Chain Wear: A worn-out timing chain in Mercedes-Benz S-Class (W222) can lead to this issue.

Investigating the Hydraulic Tappets

A common issue with hydraulic tappets in certain Mercedes-Benz models can be pinpointed to:

  • Lack of proper lubrication
  • Deteriorated tappet materials
  • Incorrect adjustments

For a detailed inspection of the tappets, you may need the following tools:

  • Tappet feeler gauge
  • Spanner set
  • Torque wrench

Should the tappets require replacement, the suitable part number for most recent models would be A2760500800.

Ensuring the Right Engine Oil Viscosity

Choosing the right engine oil is vital for your car’s performance. Here’s how you can ensure it:

  1. Select the Right Oil: Refer to your model’s manual for the correct viscosity rating.
  2. Regular Check: Monitor the oil levels and condition every month.
  3. Professional Assistance: Visit our Mercedes servicing in Bristol for expert advice.


  • Mercedes-Benz A-Class (W176): Recommended oil 5W-30
  • Mercedes-Benz GLC (X253): Recommended oil 0W-40

Addressing Timing Chain Wear

A timing chain in need of replacement is a serious matter. Here are the steps to identify and address this problem:

  • Inspecting the Chain: Use a timing light to identify wear.
  • Replacements: For an M276 engine, part number A0009932176 would be suitable.
  • Expert Care: Handling timing chains is complex, thus professional assistance might be needed.

Tips and Tricks for Cold Starts

Cold starts can be made smoother by:

  • Warming Up the Engine: A few minutes of idling helps lubricate the engine.
  • Investing in a Block Heater: Especially in the extremely cold regions.

Let’s Help You Out!

Having trouble with cold start clattering sounds? Don’t hesitate to contact our Mercedes specialists in Weston-super-Mare and drive with the assurance you deserve.

Remember, the above tips are offered as guidance and it’s always best to consult a professional as information may be incorrect or out of date.

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