2016 GLC 300 Spark Plugs Indexing?
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2016 GLC 300 Spark Plugs Indexing?
Replacing my spark plugs in a 2016 GLC 300.
Previous parts are the Mercedes branded plugs that say "NGK SILZKFR8H7S JAPAN".
New parts are "Bosch Double Iridium Spark Plug 96347"
https://www.boschsparkplugs.net/bosc...um-spark-plug#
Install went fairly smoothly but afterwards I read something about indexing and have started looking around and seen many threads arguing in many directions. It seems the consensus is: these Bosch plugs, when tightened to the correct torque spec (to 23 nm, which I did) will be indexed correctly. Is this accurate, or am I being stupid? Worried I'm causing harm if I'm driving around in this. I really did look around the forum for a while but was not able to find something definitive.
Previous parts are the Mercedes branded plugs that say "NGK SILZKFR8H7S JAPAN".
New parts are "Bosch Double Iridium Spark Plug 96347"
https://www.boschsparkplugs.net/bosc...um-spark-plug#
Install went fairly smoothly but afterwards I read something about indexing and have started looking around and seen many threads arguing in many directions. It seems the consensus is: these Bosch plugs, when tightened to the correct torque spec (to 23 nm, which I did) will be indexed correctly. Is this accurate, or am I being stupid? Worried I'm causing harm if I'm driving around in this. I really did look around the forum for a while but was not able to find something definitive.
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Joined: Jun 2025
Posts: 163
Likes: 57
From: Australia
2014 ML63, 2018 GLC43, 1929 DB victory six sports roadster
Replacing my spark plugs in a 2016 GLC 300.
Previous parts are the Mercedes branded plugs that say "NGK SILZKFR8H7S JAPAN".
New parts are "Bosch Double Iridium Spark Plug 96347"
https://www.boschsparkplugs.net/bosc...um-spark-plug#
Install went fairly smoothly but afterwards I read something about indexing and have started looking around and seen many threads arguing in many directions. It seems the consensus is: these Bosch plugs, when tightened to the correct torque spec (to 23 nm, which I did) will be indexed correctly. Is this accurate, or am I being stupid? Worried I'm causing harm if I'm driving around in this. I really did look around the forum for a while but was not able to find something definitive.
Previous parts are the Mercedes branded plugs that say "NGK SILZKFR8H7S JAPAN".
New parts are "Bosch Double Iridium Spark Plug 96347"
https://www.boschsparkplugs.net/bosc...um-spark-plug#
Install went fairly smoothly but afterwards I read something about indexing and have started looking around and seen many threads arguing in many directions. It seems the consensus is: these Bosch plugs, when tightened to the correct torque spec (to 23 nm, which I did) will be indexed correctly. Is this accurate, or am I being stupid? Worried I'm causing harm if I'm driving around in this. I really did look around the forum for a while but was not able to find something definitive.
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Joined: Oct 2009
Posts: 7,010
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
It's always a good idea to index your plugs.
The question, as I understand it, was "do Mercedes -benz plugs automatically index when torqued to the correct specifications?"
I have seen that answered affirmatively on other threads but I don't know personally.
Secondary question would be, if Mercedes plugs automatically index, do other brands do the same?
My guess is "no" to that one.
The question, as I understand it, was "do Mercedes -benz plugs automatically index when torqued to the correct specifications?"
I have seen that answered affirmatively on other threads but I don't know personally.
Secondary question would be, if Mercedes plugs automatically index, do other brands do the same?
My guess is "no" to that one.
MBWorld Fanatic!
Joined: Apr 2016
Posts: 1,124
Likes: 205
From: NW
2018 GLC 4MATIC
Originally Posted by Mattml430
Spark plugs definitely need indexing otherwise it can cause valve or cylinder wall damage. The opening of the electrode needs to be pointing at the injector or as close as you can. I’ve always used genuine plugs and they always seem to end up pretty close. I think from memory it can be + or - about 30 degrees. I put a line on my socket and line the opening of the electrode up with the injector.
BTW when I pulled my plugs first time I marked wrench just to see where electors are, answer is all over. And after two replacements with OEM plugs still all over.
