Oil in spark plug bore!

[Moose6053]

I was changing spark plugs on my wife’s 2015 V6 and on the passenger side middle plug there was oil in the bore hole, it was not on the ignition side of the plug only the top side of the one plug! Rewind a year and a half ago her sisters friend attempted to change her oil and said he knew what he was doing and drained her sealed transmission and proceeded with 6 more quarts of oil! Luckily the transmission sensor wouldn’t let it move with out the fluid so I come in and realize what he’s done and fix the issue and we have never had oil spots on our concrete or anything I cannot figure out where this oil came from! Any info would be great!

 

[mikeru]

The gasket for the spark plug hole has failed. Number 5 in the diagram below. Here's a link to the part as well.

Mopar Spark Plug Well Gasket, Right Side, Cylinder Head Cover 5184778AB | Auto Parts

2011-2024 Mopar 5184778AB - Spark Plug Well Gasket, Right Side, Cylinder Head Cover | Auto Parts

www.bamwholesaleparts.com

 

[Burla]

Try anti seize on the threads and a bunch of dielectric grease on the ceramic portion, make sure not to get it on silver tip. There can be many reasons for this, not really sure how to diagnose exactly. I would tune engine, clean air ways and throttle body, new air filter, clean combustion chamber, clean injectors and run redline si-1 for a good while, make sure the pcv is not clogged, hard to do because that engine might not have one, maybe add a vent to the valve cover to ensure no crankcase buildup pressure. Adding a vent isnt emissions legal, so hide it

 

[Burla]

The oil came from combustion chamber and it was likely pushed through threads due to excess pressure. It could be as simple as that injector not atomizing fuel correctly or something more nefarious like clogged pcv and that was weak spot. You can do more direct testing such as fuel trims or compression tests, I mean toss a mechanic an hours labor and let him to that stuff. The oil comes from the pcv, and the real question is why did it not burn when it was supposed to. It probably isnt clogged pcv because there was oil there, but it could be pcv because that is where the pressure could have came from. No way to tell all this stuff, you need to run some tests and do some maintenance.

 

[mikeru]

The oil came from combustion chamber and it was likely pushed through threads due to excess pressure. It could be as simple as that injector not atomizing fuel correctly or something more nefarious like clogged pcv and that was weak spot. You can do more direct testing such as fuel trims or compression tests, I mean toss a mechanic an hours labor and let him to that stuff. The oil comes from the pcv, and the real question is why did it not burn when it was supposed to. It probably isnt clogged pcv because there was oil there, but it could be pcv because that is where the pressure could have came from. No way to tell all this stuff, you need to run some tests and do some maintenance.

OP stated that the ignition side of the spark plug was clean. Oil was only on the exterior of the plug, above the threads. Oil cannot be pushed through the threads. Unless the spark plug was loose, the amount of pressure required to do that would blow the head gasket. Not to mention the amount of blow-by that would be produced. And if the spark plug was loose, the engine would have ran rough and they'd have heard it. The oil came from a leaking spark plug seal, as I stated above. Simple fix with a valve cover gasket kit.

 

[Burla]

Did I say it wasn't? All I said it could be many things and offered some other possibilities. And most certainly oil can make it past spark plug threads if there was a pressure issue in a combustion chamber. And even if what you say it correct, what caused it to fail? Most likely culprit, pressure from something such as faulty pcv. peace

 

[18CrewDually]

Post #2 above is spot on. And that's all I got to say.

 

[mikeru]

Did I say it wasn't? All I said it could be many things and offered some other possibilities. And most certainly oil can make it past spark plug threads if there was a pressure issue in a combustion chamber. And even if what you say it correct, what caused it to fail? Most likely culprit, pressure from something such as faulty pcv. peace

No need to get into a speculative argument over this. Why make it more complicated than it has to be? Seals and gaskets go bad. Rubber becomes plasticized over time. They can and do fail on their own. I've seen this happen on other engines with similar combustion chamber designs. It's a simple fix for the OP.

 

[Burla]

I hate to state the obvious, but knowing why something failed can be helpful in avoiding it happening again. Seals blow mostly when psi is up and that is very treatable. That engine is known for pcv issues, you can go to all the trouble of fixing it but if you don't address the psi it will just fail again, good day.