C400 Spark Plugs
05-01-2020, 12:12 PM
#1
Member
Thread Starter
C400 Spark Plugs
Anyone have any insight on the spark plug replacement recommendation. I was quoted around $550. First. I have never replaced spark plugs so early. Any opinions on whether or not this is Mercedes overdoing it or actually necessary? Also, do you you think a regular shop could do the job just as easily? I definitely don't want anyone screwing things up, but spark plugs is a pretty basic thing as far as I know. Thoughts?
05-01-2020, 05:39 PM
#4
Worst part of the job is prying the boots off the plugs. Use a cable tie, shoe lace or something to reduce the risk of damaging the plug wire. I think the plugs on the 3l are actually easier to get at than on the 3.5 engines...
05-01-2020, 07:14 PM
#5
It's so easy. Use OEM plugs, the guide posted on this forum, and but a spark plug boot puller.
The plugs cost $75 and took about an hour. You need a socket wrench, a 16mm deep socket, and a magnet stick to remove/set in the plugs. It is super easy, plenty of room to work too.
The plugs cost $75 and took about an hour. You need a socket wrench, a 16mm deep socket, and a magnet stick to remove/set in the plugs. It is super easy, plenty of room to work too.
05-01-2020, 07:15 PM
#6
05-01-2020, 07:48 PM
#7
Actually, the plugs on my '17 F150 with the 5.0 Coyote are easier to change. Nothing impedes access to the 8 coil packs mounted on top of the cam covers. Much simpler than the older 5.4 Triton. The E400 plugs are easy to access once you move the air filter housings and sound deadening foam out of the way.
Trending Topics
05-02-2020, 08:36 AM
#8
Junior Member
I have done them on my 2015 C400, they were pretty straightforward.
However, on our M276 Dela 30 engine, it's critical that the plugs be "indexed"
This requires that the installer use a calibrated torque wrench at the correct 23 N-m setting when seating each plug.
This assures that the electrode on the tip of the spark plugs is correctly lined up with the direct injection port inside the cylinder.
Use a digital torque wrench for the final tightening and make sure to use the OEM Mercedes branded plugs...as the threads on these are calibrated to line up at 23 N-m of torque.
See the attached bulletin for clarification.
However, on our M276 Dela 30 engine, it's critical that the plugs be "indexed"
This requires that the installer use a calibrated torque wrench at the correct 23 N-m setting when seating each plug.
This assures that the electrode on the tip of the spark plugs is correctly lined up with the direct injection port inside the cylinder.
Use a digital torque wrench for the final tightening and make sure to use the OEM Mercedes branded plugs...as the threads on these are calibrated to line up at 23 N-m of torque.
See the attached bulletin for clarification.
05-02-2020, 09:10 AM
#9
MBWorld Fanatic!
They're needed early due to multi-spark ignition is what I have been told. The indexing is the first I'm hearing - the PDF seems to indicate that this would be true for all 276 engines.
