MB M276 Spark Plugs at 55K miles

Getting the proper plugs for a Mercedes is not as simple as folks might believe and is very important to how the engine runs. Bosch plugs, not OE, but over the counter Bosch, have a terrible reputation in Mercedes circles. NGK Iridiums are specified for my engine, and 24 plugs are required.

A plug change on my car isn't cheap, but saving a few dollars/plug is a false economy as the engine will run badly. With coils listed at $1,400 apiece (2 required) and the voltage transformer listed at $750, getting the wrong plugs, and then chasing down a misfire gets very, very expensive, in very short order.

I would never use Bosch in that engine, from all the bad experiences other owners have had. I would use MB OEM, or NGK (the OEM supplier) ONLY!
 
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Astro14 said:
Getting the proper plugs for a Mercedes is not as simple as folks might believe and is very important to how the engine runs. Bosch plugs, not OE, but over the counter Bosch, have a terrible reputation in Mercedes circles. NGK Iridiums are specified for my engine, and 24 plugs are required.

A plug change on my car isn't cheap, but saving a few dollars/plug is a false economy as the engine will run badly. With coils listed at $1,400 apiece (2 required) and the voltage transformer listed at $750, getting the wrong plugs, and then chasing down a misfire gets very, very expensive, in very short order.

I would never use Bosch in that engine, from all the bad experiences other owners have had. I would use MB OEM, or NGK (the OEM supplier) ONLY!
Click to expand...
Are you sure NGK is the OEM supplier of plugs for the M276? Because this sure seems to contradict that.


Also, FCP lists Bosch as the OEM for these MB plugs.

Mercedes Spark Plug - Genuine Mercedes 0041598103

Mercedes Spark Plug - Genuine Mercedes 0041598103
www.fcpeuro.com

I replaced the factory installed MB plugs with the Bosch plugs when I did my 50k mile service. Unlike the visual difference shown between the MB and NGK plugs in the above MBWorld link, There was absolutely no visual difference at all between the MB plugs that I removed and the Bosch plugs that I installed. Except for the Bosch armature in place of the MB tristar.
 
BHopkins said:
Are you sure NGK is the OEM supplier of plugs for the M276? Because this sure seems to contradict that.


Also, FCP lists Bosch as the OEM for these MB plugs.

Mercedes Spark Plug - Genuine Mercedes 0041598103

Mercedes Spark Plug - Genuine Mercedes 0041598103
www.fcpeuro.com

I replaced the factory installed MB plugs with the Bosch plugs when I did my 50k mile service. Unlike the visual difference shown between the MB and NGK plugs in the above MBWorld link, There was absolutely no visual difference at all between the MB plugs that I removed and the Bosch plugs that I installed. Except for the Bosch armature in place of the MB tristar.
Click to expand...
I was talking about my engine. The M275. A slightly different one than yours, and yes, I am certain that NGK is the OEM supplier of MB plugs for that engine.
 
BHopkins said:
Are you sure NGK is the OEM supplier of plugs for the M276? Because this sure seems to contradict that.
Click to expand...
I think they switched suppliers. Some of the Bosch plugs sold on Amazon seem to be fakes. I also have the NGKs in my M272. You would hope someone like FCP or Rockauto would have better control of their channel and not sell fakes. In theory with the OEM plugs on the M276, they only go in one way so they will index correctly. Indexing has been around a long time, I believe what you do is mark a spot on the plug, put it in and see where that mark lines up to see if it is indexed correctly. Of course with the plugs hard to get to, it might be hard to actually see the mark you put on the plug. I used to do it back in the 90's when I had a car with a turbo but it didn't seem to matter that much or the amount was so little that I didn't bother afterwards. You had various sized copper washers to adjust the distance.
 
Wolf359 said:
I just got another email from MB offering their $150 off $300 service from Dec 1 - Jan 31st. They always do this a couple times a year though.
Click to expand...
I got the same offer last month, did the transmission service on the W212 for ONLY $310, such a deal!

Is spark plug indexing so critical on the M272 engines as well or can I run over the counter Bosch/NGK from someone like FCP?
 
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Do not run any brand inc NGK aftermarket plugs that require indexing in a MB engine. Yes it is critical.
Most people just go by torque and that will get them close enough but marking the top of the socket aligned with the ground electrode open end will allow you to get it spot on.
Start off with going a couple of Nm under and see where the electrode is, anywhere in the range of 2 Nm under or over will usually get it dead nuts on.


Edit: On these engines do not use anti seize, the specified 23Nm torque spec is only to get the electrode in the range. These plugs also use a solid copper ring that acts as an indexing washer also.
 
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Egg_Head said:
I got the same offer last month, did the transmission service on the W212 for ONLY $310, such a deal!

Is spark plug indexing so critical on the M272 engines as well or can I run over the counter Bosch/NGK from someone like FCP?
Click to expand...
Indexing isn't an issue on the M272, they started that on the M276. I got laser platnium NGK's at Rockauto for the plugs, but that might be overdoing it.
 
Egg_Head said:
I got the same offer last month, did the transmission service on the W212 for ONLY $310, such a deal!

Is spark plug indexing so critical on the M272 engines as well or can I run over the counter Bosch/NGK from someone like FCP?
Click to expand...
That is a good deal for the trans service. Our local dealer charges $600 for the 722.9 trans service which involves the pan drop and 4.5-5 quarts of blue or red fluid. I would strongly consider doing it yourself, btw. It is not a difficult task at all. You can get all of the parts to do the job for under $150, possibly under $100.

Trav said:
Do not run any brand inc NGK aftermarket plugs that require indexing in a MB engine. Yes it is critical.
Most people just go by torque and that will get them close enough but marking the top of the socket aligned with the ground electrode open end will allow you to get it spot on.
Start off with going a couple of Nm under and see where the electrode is, anywhere in the range of 2 Nm under or over will usually get it dead nuts on.


Edit: On these engines do not use anti seize, the specified 23Nm torque spec is only to get the electrode in the range. These plugs also use a solid copper ring that acts as an indexing washer also.
Click to expand...
When torquing these plugs, it is obvious that the copper ring does not crush. The feel is very different than most spark plugs. It feels like you are torquing a flange bolt that contains a washer.

As previously mentioned, torquing new dealer plugs to 17 ft-lbs/23 nm is sufficient. Indexing in the way you described may be ideal, but probably is not necessary.
 
The MB PDF said the NGK plug pictured was not the correct heat range. That would mean it is NOT the correct plug for that application, so I wouldn't expect it to index correctly, either.
 
This is somewhat unrelated. When the car was due for its first plug change at 50K, the #5 plug (center plug, driver side bank) did not want to come out after a few turns. The owner eventually took the car to the dealer (at 75k) and requested a spark plug replacement. The dealer experienced the same issue and installed a new cylinder head under CPO warranty. I had no issues with the spark plug replacement during the most recent service, which is 55K after the new cylinder head was installed.

Shown below is a picture of the damaged spark plug that was removed. This was the factory-installed plug. What do you think happened?
 

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Oh yeah a thread about this popped up in the W212 E class forum, I guess you can use the Bosch plugs, but need different sized copper washers.

mbworld.org

Are Spark Plugs available for 'M278 engine - MBWorld.org Forums

E-Class (W212) - Are Spark Plugs available for 'M278 engine - I ordered the supposedly correct Mercedes brand spark plugs for my 2012 E550 with the M278 engine. Pert number A 004 159 81 03 I bought 9 of them, plus a spare coil, plus 2 spare wires, the offset wrench and the socket with the...
mbworld.org

Probably not worth the hassle for a shop but might work for those who like to DIY.
 
Egg_Head said:
I got the same offer last month, did the transmission service on the W212 for ONLY $310, such a deal!

Is spark plug indexing so critical on the M272 engines as well or can I run over the counter Bosch/NGK from someone like FCP?
Click to expand...

7g tropic plus ATF swap is $450 at a dealer? I paid ~$700 at two different dealerships, in different states on my 15’ E350 4matic
 
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