Help! Oil on spark plug threads...

Hey fellas just doing maintenance on the 4.0L and when I took out spark plug #5 (driver side closest to firewall) there was oil on the spark plug threads. Not a lot but you can definitely get oil on your hand by holding it by the threads. What do you guys think this is caused by??? I'm hoping just bad valve cover gaskets and not bad rings in the cylinder. The very tip of the spark plug looks ok I guess. I have 140,000 mi on the motor. Any opinions???

 

worst case scenario engine rings....but it could just be your PCV valve (easiest fix ever) if the PCV valve is plugged or inoperative, it can cause a buildup of crankcase pressure. This condition can force oil and oil vapors past the rings and valve guides into the combustion chamber.

 

valve cover gasket? same problem in my old accord, easy fix

 

EVERY time i've had oil on myspark plug threads its been a valve cover gasket or oil I spilled down the spark plug hole.

Not that there aren't other reasons. But in my limited experience, that's what I've seen.

 

Really? Why?

 

yea. on threads it pretty much has to be, at worst, a valve cover gasket. If its not filling the well, its no threat, just keep an eye on it. If its on the electrode that's trouble.

 

Thanks for the replies...Hopefully its just a gasket another weekend project....The electrode looks pretty normal at best im going to keep an eye on it....Would this problem have anything to do with loss of power or compression???

 

no. No effect on cylinders.. Are you having those? I mean, there's a tiny chance you could have a cracked head, but its pretty tiny.

 

I have had a loss of power After I changed my plugs 30,000 mi ago with factory plugs....I had the loss of power right after....I even put the old plugs back in to see if it goes back to normal but no luck. Since then I changed the maf sensor and tried locating a vacuum leak or something even changed the fuel pump but nothing. Once in a while Ill have it come back to life for about 10 to 15 min then feels sluggish again. Had check engine light come on for about three hours and went away, it was "bank1 to lean" forgot the code. So Im baffeled

 

Maybe you have a bad catylitic converter or clogged injector. Bad O2 sensor.
I haven't been under the hood too much. This truck have the coils on the top of the plugs?

DOubt your oil on the plug is related. I'd tell you you were imagining it if you never had a code.
Have you pulled your codes other than that one? "pending" codes.

 

Make sure to read your sensors and find out if they are reading true. If a temp sensor is inaccurate, your fuel mix will be off.

 

Another symptom I forgot to mention is when I take off I give it gas but I dont have that "feeling of getting pushed back in the seat even a little" it just goes then when I reach past 2500 rpms it kicks in and goes and this is just moderate driving. It does have coil plugs on top of them and I'll look into the temp sensor if i could find it.

 

Just noticed the same thing on Mine... I have 52k miles and the same plug (driver side closest to firewall) had oil on the threads and there was a small amount of oil down in there...

Bought it used at 46k and I don't think the plugs were ever changed....

I am thinking about buying a valve cover gasket and replacing mine... but at 52k miles??????? Seems a little soon for something like that...

It's an '06

 

Unless I wanted to do it for the fun of it I wouldn't bother with it. What's the worse it can do? cause a mis-fire?

I'm not sure it will that, based on what I've seen: my old truck used to fill all it's wells and it never misfired. I also know a couple people who's plug wells on their Maxima's fill up with never a misfire. I just don't see the problem leaving it alone unless you do see some kind of secondary effect.

 

Hmm well after reading what Chris4x4 said I feel a little better....

Glad I found this thread...

Guess I could pull the boot at 15k and check for more oil....

 

Dont even bother, oil there is from vacum line coming from valve cover. So no need for new gasket. Its the way it works

 

I have oil on all of my spark plug threads, had it for a year now, checked everything, but was unable to find the cause, lets continue this thread maybe someone more experienced will chime in and tell us what the hell causes this

 

You did plug the plug wires back in proper order, right?! I recall a buddy in HS just unplugging all w/o paying attn and had no clue there was an order to them.