Mercedes-Benz Spark Plug Procedures and Precautions

by | Apr 2021 | 2 comments

This essential component was invented about 160 years ago, but is still evolving in terms of design, materials, and service.

Ah, the lowly humble spark plug. At one time it was king of the ignition system (or at least part of the royal court!). I...

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  1. twilighthan

    In the M157 engine, WIS does not state anything about the direction of the electrode gap. Also, for me it was impossible to see anything after I put the spark plug on to tell what direction it is in. Is there any best practices in spark plug installs for the M157 anyone knows of?

    • Automotive Tech Info

      The “Mercedes-Benz Spark Plug Indexing for Direct Injection Engines” Bulletin explains that on all direct injected MB engines (of which the M157 is), you should use only genuine MB spark plugs. To check your index put a mark on the porcelain in the direction of the electrode to see where it faces when installed. You may need a mirror to see it in its recess. We’ve added a button (above) to download the Spark Plug bulletin. We hope that helps.

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