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Great pix to see!

And I stand corrected ... you have a good point cuz a tough ping (bad tune) at the wrong spot in the flame front could do a number on the piston and not on its crown either

So the C is not quite the grandpa mobile ay?
Not at all! It's way sportier than the cla, handles way better. It's definitely a huge upgrade with zero grandpa factor. Consider that this is the same as a C43 AMG.


1,730 Posts
This guide will walk you through a 60k spark plug service for the CLA250 M270 engine. Service manual recommends changing the plugs every 60k miles. I did mine @ 63569. The internet has very scarce instructions/video at this point. Most CLA owners probably has not reached 60K yet. Special thanks to youtube channel @UnboxWorld for making a video for the 1.6T engine.

Make sure the engine is cold and the car is in "sleep mode" before doing any of these steps. Keep the keyfob away from the car and open the driver side door. The car is in sleep mode once the interior lights turn off. At this point, do not wake the car by closing/opening any of the doors or the trunk.

Tools needed:

Torx set
Socket / ratchet set (with extensions)
Flat head screwdriver
3pcs 18.5 oetiker clamps
Oetiker wrench
14mm 12 point spark plug socket THIN WALL
Torque wrench (very important!)

Air compressor
Blow gun

4 spark plugs (NGK SILZKFR8E7S)
Spark plug lubricating grease A002-989-80-51

Remove the 3 torx screws from the airbox neck (green circle) and loosen the two hose clamps (red circle).

View attachment 61840

Detach electronic connectors (green arrows), then detach vacuum lines (red arrows). There are a lot of videos on how to remove oetiker clamps. All you need is a flathead really.
1. Vent line
2. Wide open throttle heater element vent line
3. and 4. purge lines

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Remove the intake pipe by sliding it to the left. The intake pipe will need to go under the non-removable cables (see first picture)

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Detach electronic connectors from the coils.

Remove the coil screws. Note that the spark plug boots are at an angle. You may use the ring spanner side of a wrench to pull the coil, using the pull tabs.

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Prior to removing the plugs, use compressed air to blow gun loose debris. You don't want any debris falling off in your cylinders when you remove the sparks plus. An air can is a no no. Use compressed air with at least 90psi pressure.

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Using your spark plug thin-wall socket, slowly turn counter-clockwise. Mercedes does not recommend using anti-seize on the threads so you will hear metal to metal as you turn. There will most likely rust too (as mine did).
Remove and replace plugs one at a time.

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Since rust from the thread might have fallen off inside the cylinders, it is a good idea to vacuum the canal before installing new plugs. I just improvised and cut a piece of tube and shrink-wrapped it on my vacuum extension.

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Picard > A YouTuber, "CapCustoms" made a video on 11/16/18 titled How To Change 2014-2018 MB CLA250 Spark Plug.
He used a link showing all of your photos, in his 3rd reply to a viewer, (dthomas5768), comment...Like others have are a famous celebrity 馃弳.

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1,730 Posts
... "CapCustoms" made a video on 11/16/18 titled How To Change 2014-2018 MB CLA250 Spark Plug.
Looks like you will have to key title in.
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