How to change spark plugs on Mercedes-Benz 2.0L 4 Cylinder Turbo M274 M270

In this guide, you will learn how to change spark plugs and ignition coils on Mercedes-Benz 2.0L four-cylinder engine known as M274 and M270. 

This engine is installed on many Mercedes-Benz cars and SUVs including 2015+ C-Class W205, 2013+ E-Class W212, 2015+ SLK Class R172, 2013+ GLK Class X204, 2015+ GLC Class. For more details see application list below. 

What you will need


  • Park your Mercedes-Benz on level ground and allow the engine to cool downw205 spark plug diy


  • Pull the hood release under the dashboard and open the hood. open hood w205


  • Remove the engine cover by pulling it up. The cover simply snaps on top of the engine. There are no screws to remove. remove engine cover
  • Locate the ignition coils. Remove the T25 Torx bolts that secure the ignition coil to the engine. t25 boltsEach ignition coil has two bolts.  t25 ignition coil bolts w205 c class
  • Remove the ignition coil and the boot from the engine. If you are replacing only the spark plugs, you don't need to disconnect the ignition coil.
    The boot that goes from the ignition coil to the spark plug will need to be pulled out. Spark plug boot requires force to come out. spark plug ignition coil


  • Insert the 14mm spark plug tool in and remove the spark plug by turning it counterclockwise. remove spark plug m274 mercedes four cylinder engineNote that you need a specific tool to remove the spark plug. If you are using a 14mm socket it needs to have thin walls or it will not go inside the hole. 
  • Reinstall the new spark plugs and torque to 25 Nm. When you first insert the spark plug, start threading them by hand to avoid cross threading. install spark plugs


  • Reinstall the boots, ignition coil and torque two ignition coil torx bolts to 10 Nm.spark plug boot
  • Replace the engine cover and start the engine. To install the engine cover, line it up the oil cap then press down on the cover. 

    engine cover


  • 015–present W205 C160
  • 2012–2013 W204 C180
  • 2013–2016 W212 E180
  • 2013–2016 W212 E200 Natural Gas Drive
  • 2013–2016 W212 E200
  • 2013–2016 X204 GLK200
  • 2014–2018 W205 C200
  • 2015–present R172 SLK200
  • 2016–present W213 E200
  • 2013–2016 W212 E250
  • 2013–2016 X204 GLK250
  • 2014–2018 W205 C250
  • 2015–2018 W205 C350e
  • 2016–present W213 E250
  • 2016–present W213 E350e
  • 2015–2018 W205 C300
  • 2015–2018 W213 E300
  • 2015–present X253 GLC300
  • 2015–present R172 SLK300

The same engine is installed on some 2015 and newer Infiniti Q50 Q60 Q70. 

Torque Specifications

  • Spark Plugs: 25 Nm  (18.44 ft-lb
  • Ignition Coil Bolts: 10 Nm (7.38 ft-lb)


Drew, 2019-09-25

Awesome write up. One question - how do you pull the spark plug boot without tearing anything? Do you apply any silicone dielectric grease to prevent it from sticking?

By YOUCANIC on May 24, 2019


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