Defective Bosch spark plug

[Chris142]

I put 6 plugs in a 2014,Mercedes E350. Got a missfire on #6. Pulled the coil to make sure that I didnt miss the plug with the boot.....Ok.

Swapped 2 coils. no change. Pulled the plug. Gap is good,Porcelin isnt broken.

Put an old plug back in that cyl and the miss is fixed.
Currantly waiting on another plug to be delivered.

 

[Andyd95]

Genuine plugs only for a M276
https://automotivetechinfo.com/wp-c...enz-Spark-Plug-Procedures-and-Precautions.pdf

 

[Astro14]

Fake?

That engine is pretty picky about plugs - they’re “indexed” meaning the electrode is pointed in a particular direction when fully torqued.

I wouldn’t even use Bosch because they’re probably not indexed.

Genuine Mercedes only…

 

[slacktide_bitog]

Is Bosch the OE supplier, or is it NGK?

These plugs have special indexing requirements, too

 

[Astro14]

Mine are NGK - I suspect the Mercedes plugs for this engine are NGK as well.

Also, these should be Iridium. Double platinum might be the wrong choice for this engine.

Did the customer supply these?

 

[The Critic]

I have used those plugs in 276's without issue, but they look very different than the real MB plugs.

They would not be my first choice.

 

[Chris142]

Mine are NGK - I suspect the Mercedes plugs for this engine are NGK as well.

Also, these should be Iridium. Double platinum might be the wrong choice for this engine.

Did the customer supply these?

Fake?

That engine is pretty picky about plugs - they’re “indexed” meaning the electrode is pointed in a particular direction when fully torqued.

I wouldn’t even use Bosch because they’re probably not indexed.

Genuine Mercedes only…

They are double Irridium. They came from the dealer. They delivered them about 10a this morning. The ones I took out were the same. According to our records they have never been changed.. But the old ones didnt have the mercedes mark on them.

 

[The Critic]

They are double Irridium. They came from the dealer. They delivered them about 10a this morning. The ones I took out were the same. According to our records they have never been changed.. But the old ones didnt have the mercedes mark on them.

The MB ones have the mark on them. Someone’s lying to you - those plugs definitely do not look like Genuine MB plugs.

Here is a picture from the last set I installed. Bosch vs. Genuine MB, you can see a clear difference in the electrode design.

 

[Chris142]

The MB ones have the mark on them. Someone’s lying to you - those plugs definitely do not look like Genuine MB plugs.

Here is a picture from the last set I installed. Bosch vs. Genuine MB, you can see a clear difference in the electrode design.

View attachment 244527

I saw the van pull up and the Mercedes guy walked them to me. I would not be suprised if they didnt have the actual mercedes plugs and sent these.

 

[The Critic]

I saw the van pull up and the Mercedes guy walked them to me. I would not be suprised if they didnt have the actual mercedes plugs and sent these.

MB box or Bosch box?

 

[Chris142]

MB box or Bosch box?

Bosch