Engine sounding like Subaru idle

[erickhoyos]

Hey guys, just recently I was pulling in to wash my car when all of a sudden I felt a weird rumble to my car when I noticed the idle of my car was uneven and whenever I revved it it started to sound like a boxer engine. I also noticed that the temps to the car were strangely very high for outside temp being around 75 degrees. There seems to be no coolant leaks and the car hasn’t ran for over a week until now. No spirited driving, just some highway driving and city driving. Don’t know what it could possibly be.

[jet_dogg]

Probably a coil, take it to someone.

[erickhoyos]

Was doing some testing and found out that the spark plug tip for cylinder 5 broke and stuck inside the ignition coil. Luckily nothing too crazy

[erickhoyos]

Pulling plugs and all of them minus cylinder 6 are drenched in oil. Can that be a sign of a bad head gasket?

[Mr.wReckless]

I would have thought if the plugs are oily it's a bad seal, either a piston ring or valve stem seal, alternatively the PCV could have swallowed some oil somehow and it following the path of the intake into the combustion chamber. The head gasket is for the water jackets and coolant so I don't see how that would make the plugs oily?

Regards

[SpaceJockey]

Oily plug could simply be the valve cover grommet leaking for that plug cylinder. The plug might be getting oily as you pull it out. I'd look for evidence of that. That would be best case scenario.

[mrgizmo04]

Spark plug aluminum tubes sit higher than the valve cover, so leaking grommets or leaking spark plug tube seals can not contribute oil to spark plugs. Run a wet vs dry compression test to see if you got ring issues. Do you have colored smoke out of the tailpipes on cold start? Valve seals might be going.

Sent from my SM-G950U using Tapatalk

[sapote]

Spark plug aluminum tubes sit higher than the valve cover, so leaking grommets or leaking spark plug tube seals can not contribute oil to spark plugs.

1. Spark plug aluminum tubes sit higher than the valve cover. True, however this is not a lake but oil spraying everywhere, and a leaky valve cover gasket will let oil leaking into the plug hole.

[sapote]

My bad, the M3 tubes is way higher than the gasket sealing surface, and so it the gasket is leaking then the valve cover top is covered with oil, but oil should not leak into the spark plug holes.

[sapote]

Pulling plugs and all of them minus cylinder 6 are drenched in oil. Can that be a sign of a bad head gasket?

Pics of the plugs? The tips are covered with oil but the body above the threads are dry? And you don't see blue smoke from burning oil?

[erickhoyos]

Pics of the plugs? The tips are covered with oil but the body above the threads are dry? And you don't see blue smoke from burning oil?

Unfortunately I didn’t take any pics, the only best way I can describe it is that the threads were covered completely in oil and a little bit of the tip of the ignition coils had oil too except cylinder #6. As of right now there hasn’t been any smoke coming out of the exhaust, I have yet to check the spark plugs again for oil. I’ll update next week when I get a chance.

[sapote]

Unfortunately I didn’t take any pics, the only best way I can describe it is that the threads were covered completely in oil and a little bit of the tip of the ignition coils had oil too

So the oil got into the holes, and when the plugs were removed, oil flowing down and covered the plug threads. But how did the oil get into the plug holes as I don't think all 5 plugs were loose in there?