Do you feel your Mercedes-Benz loud engine idling, trouble starting the engine, the engine misfires, and the check engine light is on? Learn how to fix the problem by replacing the spark plugs of your Mercedes-Benz.
This M274/M270 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, and 2015+ GLC Class. For more details, see the application list below.
Video
What you will need
- Mercedes M274 Spark Plugs (4)
- Iridium Electrode
- Part Number: 0041597003
- 14mm Spark Plug Tool
- Thin walls
- T25 Torx Bit
- 3/8″ Torque wrench
- 4″ 3/8″ Drive Extension
Procedure
- Park your Mercedes-Benz on level ground and allow the engine to cool down.
- Pull the hood release under the dashboard and open the hood.
- Remove the engine cover by pulling it up. The cover simply snaps on top of the engine. There are no screws to remove.
- Locate the ignition coils. Remove the T25 Torx bolts that secure the ignition coil to the engine. Each ignition coil has two bolts.
- 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 from the ignition coil to the spark plug will need to be pulled out. Spark plug boot requires force to come out.
- Insert the 14mm spark plug tool in and remove the spark plug by turning it counterclockwise. Note 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 inserting the spark plug, start threading them by hand to avoid cross-threading.
- Reinstall the boots, ignition coil, and torque two ignition coil Torx bolts to 10 Nm.
- Replace the engine cover and start the engine. To install the engine cover, line it up with the oil cap, then press down on the cover.
Each ignition coil has two bolts. 
Note 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.
Applications
- 2015 – 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)
Check Engine Still On
If the check engine light is still on after you have replaced the spark plugs, you will need to clear the stored codes on your Mercedes-Benz. The YOUCANIC Full System Scanner can read and clear fault codes through every control module of your Mercedes-Benz vehicle.
We hope you find the Mercedes-Benz M274 M270 Spark Plug Replacement | 2.0L Turbo guides helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.
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?