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Discussion Starter · #1 ·
I'm changing my spark plugs due to a misfire, and noticed a some oil in the spark plugs well. The ignition coil itself looks alright, but was loose when I went to pull it. My first thought is that the spark plug was loose and allowed a bit of blowby. Any thoughts?
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2005 330xi Auto, 2006 330ci Vert Auto
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I'm changing my spark plugs due to a misfire, and noticed a some oil in the spark plugs well. The ignition coil itself looks alright, but was loose when I went to pull it. My first thought is that the spark plug was loose and allowed a bit of blowby. Any thoughts? View attachment 955357
When you removed the spark plug, was it loose or not?
 

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Discussion Starter · #4 · (Edited)
When you removed the spark plug, was it loose or not?
Yeah, I'd say it was more loose than the other ones. It was still threaded in there (I think), but it didn't require as much torque (if any) to break it free. Also, I'm not sure if this is just me being stupid, but when I was trying to screw the plug in, it wasn't going all that easily. I tightened it down by hand, but when i went in with the torque wrench it felt like it wasn't giving much resistance at all. After I took it out again it looked like it didn't thread in all the way. Might've just been gunk in the threads, but idk. I went in a second time just hand tightening and it got deeper with a normal amount of resistance, but I let off before it was tight because I got scared that the threads might be damaged. I didn't try a third time because it got dark out while I was investigating what might've caused the oil or whatever that is to get in there in the first place.
 

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Yeah, I'd say it was more loose than the other ones. It was still threaded in there (I think), but it didn't require as much torque (if any) to break it free. Also, I'm not sure if this is just me being stupid, but when I was trying to screw the plug in, it wasn't going all that easily. I tightened it down by hand, but when i went in with the torque wrench it felt like it wasn't giving much resistance at all. After I took it out again it looked like it didn't thread in all the way. Might've just been gunk in the threads, but idk. I went in a second time just hand tightening and it got deeper with a normal amount of resistance, but I let off before it was tight because I got scared that the threads might be damaged. I didn't try a third time because it got dark out while I was investigating what might've caused the oil or whatever that is to get in there in the first place.
I would investigate whether your valve cover gasket is leaking.
 

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Discussion Starter · #6 ·
I would investigate whether your valve cover gasket is leaking.
Where should I start with that? I don't suppose a leak down test would narrow things down at all, since that would indicate a bad head gasket or piston rings. I haven't really noticed any oil consumption, although I'll admit I haven't been as diligent with checking in the past few months. Any typical places for leaks or failures I should check?
 

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I think you’re overthinking this. Clean the oil and torque the spark plug properly, then check up again in a couple weeks. If theres still oil in the spark plug hole it’s the valve cover gasket. It’s a very common issue and a quick and easy job.

It’s got nothing to do with blowby or oil consumption, just some oil weeping.

I doubt the spark plug was loose and letting oil through
 

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Discussion Starter · #10 ·
Alright, just ordered a new valve cover gasket. Even if it's not exactly the culprit, it would be nice to have the maintenance done. Feels like I'm always on the back foot with this car :/. Hopefully that'll get better as I keep ticking off 2nd round 100k maintenance items.
 

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It's either that or you added oil to the engine, in the process spilled a copious amount around the neck and it went under the beauty cover and found it's way to there....
 

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Discussion Starter · #12 ·
It's either that or you added oil to the engine, in the process spilled a copious amount around the neck and it went under the beauty cover and found it's way to there....
I'd hope not. Last oil change I got done was at a pretty reputable place since I didn't have access to my jack, so I hope they didn't overfill it. There isn't any oil residue or anything visible underneath the vanity cover tho.
 

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Not "overfill" but spill.
However you state it's clean under the beauty cover. Has to be a VC gasket.

Besides over filling (as long as 1L or less) would not do such.
 

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I'm changing my spark plugs due to a misfire, and noticed a some oil in the spark plugs well. The ignition coil itself looks alright, but was loose when I went to pull it. My first thought is that the spark plug was loose and allowed a bit of blowby. Any thoughts?
What you wrote in the first post looks like it says that the COIL was loose - was the coil loose, or was the actual spark plug loose?

Anyway, oil in the plug well and on the back end of the plug is, as everyone else has pointed out, a leaking valve cover gasket, or someone missed the oil filler and poured oil over the top of the engine. I’d carefully clean it out (shop rags, brake clean or other solvent, and compressed air - be sure you don’t wash any grime into the cylinder through the spark plug hole if you have the plug removed). If you can, remove the plug and clean out the threads the spark plug screws into. A twisted paper towel or a shop rag held in a hemostat or one of those extra-long Q-tips works well for this. A thread chaser may also help, if you’re having problems screwing in the new plug. Once you’re done cleaning things up, screw in the new plug by hand until the washer contacts the head, then torque with your torque wrench…While you’re at it, I’d also suggest removing the rubber boot from the coil and giving that (along with the wire spring inside the rubber boot, that goes between the end of the plug and the coil) a good clean, too. A dab of dielectric grease between the rubber boot and the porcelain on the spark plug will also help seal out any fluids that get into the spark plug well…
 
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