M111.951 spark plug gap
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Junior Member
Joined: Apr 2025
Posts: 44
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W203 C180 M111.951
M111.951 spark plug gap
Just saw the must read for newbies, and before I get roasted or given a warning, I di use the search bar to search for M111.9951 spark plug gap without success :-)
So I would like to do a service, plugs, filters, oil etc, and Im a bit confused as to what the plug gap must be. Google shows 0.7mm, 0.8mm and some say 1mm. Is this plug dependent or am I just overly concerned. The plugs I intend using is the NGK IFR6D-10 or 11. Also, what are the downside, if any, of going with the wrong gap.
Thank you
So I would like to do a service, plugs, filters, oil etc, and Im a bit confused as to what the plug gap must be. Google shows 0.7mm, 0.8mm and some say 1mm. Is this plug dependent or am I just overly concerned. The plugs I intend using is the NGK IFR6D-10 or 11. Also, what are the downside, if any, of going with the wrong gap.
Thank you
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,263
Likes: 169
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Assuming you get the stock plugs which are Laser Iridium NGK 5344 also known as IFR6D10
you do not gap them or you may damage them. You can get a set of 4 last I checked for about $40 on ebay.
Just replace them every 40k ish miles or so 50K tops
Forget 100k. As the plugs get older it puts stress on the coil packs and you end up
recplacing coil packs when whats needed is new sparrk plugs.
I ended up with a pile of coil packs that worked just fine with new plugs.
you do not gap them or you may damage them. You can get a set of 4 last I checked for about $40 on ebay.
Just replace them every 40k ish miles or so 50K tops
Forget 100k. As the plugs get older it puts stress on the coil packs and you end up
recplacing coil packs when whats needed is new sparrk plugs.
I ended up with a pile of coil packs that worked just fine with new plugs.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,263
Likes: 169
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Vert true about the heat. I always keep a spare with me. Sux being stuck driving any distance with only three cylinders. Believe me I've done it. And not and easy part to find in a pinch.
