Mercedes-Benz M274 M270 Spark Plug Replacement | 2.0L Turbo
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Is your Mercedes-Benz idling rough, misfiring or showing a check engine light, or simply due for new spark plugs? Learn how to fix the problem by replacing the spark plugs of your Mercedes-Benz.
At a Glance
- Engine: Mercedes M274 and M270 2.0L turbo four cylinder
- Plugs: 4 iridium plugs, part number 0041597003
- Tools: thin wall 14mm spark plug socket, T25 Torx bit, 3/8 torque wrench
- Torque: spark plugs 25 Nm; ignition coil bolts 10 Nm
- Engine cold: let it cool fully before removing plugs from the aluminum head
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. You don’t need to disconnect the ignition coil if you are replacing only the spark plugs. The boot from the ignition coil to the spark plug must be pulled out. The 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 use 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 and 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 use a 14mm socket, it needs to have thin walls, or it will not go inside the hole.
Applications
- 2015 to present W205 C160
- 2012 to 2013 W204 C180
- 2013 to 2016 W212 E180
- 2013 to 2016 W212 E200 Natural Gas Drive
- 2013 to 2016 W212 E200
- 2013 to 2016 X204 GLK200
- 2014 to 2018 W205 C200
- 2015-present R172 SLK200
- 2016-present W213 E200
- 2013 to 2016 W212 E250
- 2013 to 2016 X204 GLK250
- 2014 to 2018 W205 C250
- 2015 to 2018 W205 C350e
- 2016-present W213 E250
- 2016-present W213 E350e
- 2015 to 2018 W205 C300
- 2015 to 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.
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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 UCAN-II Pro can read and clear fault codes in the engine and other control modules on supported vehicles-Benz vehicle, if it is supported.
Tips for a Trouble Free Plug Change
- Blow out the plug wells with compressed air before removing the plugs, so dirt cannot fall into the cylinders.
- Start each new plug by hand to avoid cross threading the aluminum head.
- Torque the plugs to 25 Nm. Overtightening can damage the threads; undertightening can let the plug loosen.
- Check the coil boots for cracks or oil. Oil in the plug wells points to a leaking valve cover gasket.
Frequently Asked Questions
How often should M274 spark plugs be replaced?
Follow the interval in your Mercedes maintenance schedule or the service reminder. Turbo engines are hard on plugs, so replace them on time.
Can bad spark plugs cause a misfire code on a Mercedes?
Yes. Worn plugs are a common cause of misfire codes such as P0300 to P0304. Check the coils and boots at the same time.
What torque do M274 spark plugs need?
25 Nm, and the ignition coil bolts 10 Nm, as listed in the procedure above.
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?