Green crap on coil

[rowsdower]

2011 N51 with 80k miles, 20k on these plugs and 2k on Delphi GN10571 coils

I got a cylinder 4 misfire code the other day, but didn't feel a misfire. I was checking for other codes and happened to find this one. I pulled the coils and plugs just now and all the plugs are close to spec at 0.047" and they look fine (even coloring). The only thing I noticed was that the coil on plug #4 has a green lubricant or adhesive on the tip where it contacts the plug, and none of the other coils have it. Anyone know if this should have been removed prior to installing?

If the green stuff is not an issue, I'm thinking my misfire is a fluke or possibly related to a failed O2 sensor.

[Pig Farmer]

Could be dielectric grease, but I’ve only seen it come in clear. The only green “lubricant” i’ve come across on a modern BMW is the power steering fluid (Pentosin CHF 11S). Probably a long shot that some of the power steering fluid made it into the spark plug hole.

[rowsdower]

Originally Posted by Pig Farmer

Could be dielectric grease, but I’ve only seen it come in clear. The only green “lubricant” i’ve come across on a modern BMW is the power steering fluid (Pentosin CHF 11S). Probably a long shot that some of the power steering fluid made it into the spark plug hole.

Nah, this is like neon highlighter green and clearly not PS fluid. I wiped it off as best I could and moved the coil to #1 to see if I get a misfire there... the car has been running fine though.

[Dogeeseegod]

COOLANT...

[rowsdower]

It’s not coolant. I should clarify that this one coil came out of the box with green stuff on it, the other 5 were clean. The green stuff is not from my car, it is from the manufacturer. I just assumed when I first installed them that it was a type of grease and that one of the coils was from a different production run, but I didn’t really think much of it. Probably just a coincidence that I am getting a misfire code for that same cylinder.

[Dogeeseegod]

Well that's a relief! Did cleaning it keep the code from kicking on or do you still believe it to be the O2 sensor? I wouldn't think it would be throwing a code for misfire from a faulty O2 sensor. Are you running aftermarket sensors with a new header or cat back?

[rowsdower]

I have headers with the stock O2 sensors, but I know they commonly fail after a header install. I don’t know if the code has come back yet - will check after my drive home later.