Oil on top of Spark Plug

I changed the plugs in my 2013 Tacoma 4.0 v6 today. One of the plugs had oil on the top side of the plug and had a stain pictured below. Is this concerning or a problem, truck runs great and I don’t have any problems.... it had 154k on the original plugs.

I can’t figure how to get the picture to load from my phone...

 

Probably the valve cover leaking around the spark plug tube..

 

Cheap fix but catastrophic if you dont repce your spark plug tube seals immediately . M engine overheated and was ruined when I thought I could make it driving to the mechanics shop. I should have towed it. Ended up buying a replacement engine on my civic

 

How did an oil leak in the spark plug tube cause over heating? Yea I would get it fixed but I wouldn’t consider it an emergency.

 

@scottalot - here is a pic of the stained plug. It had oil on it and the coil tube I pulled out had some also. Not sure if I should be concerned or need to fix anything... what seal did they replace on yours?

 

Looks like a corona stain. It’s normal.

 

Yep.. don’t worry about it.. this link explains the stain
https://www.tirereview.com/five-things-need-know-spark-plugs/

 

Yeah, I wouldn't worry about that. I do always put some dielectric grease in the opening of the boot before I put them back into the engine. If you had an oil leak there, the plug would be wet with oil, even down onto the steel hex portion.

 

No. Just no that is so wrong.

 

Just to clear up some misconception. The 1GR-FE doesn't have a spark plug tube exactly.
You should just have a gasket seal between the valve cover and the casting of the cylinder head and the valve cover.

( disregard the arrows as these images were taken from other posts. )





This is the old style below. Notice the individual tubes for each spark plug that is installed into the head: Notice that what holds the valve cover to the head is the spark plug tubes as there are no bolts or bolt holes around the head. There would be a large nut that screws onto the top of the tube to hold the valve cover on. You can see the threads at the top of the tube.

 

If you do decide to do the gaskets.
Makes sure to use some sealant in the right spots.

https://www.tacomaworld.com/threads...over-leak-gasket-replacement-and-more.479612/

 

I've seen it on motorcycles. Blows out all the oil and then gets hot.

edit: this is just to say it 'can' happen.

 

Well obviously if you run an engine without oil it is going to seize.
On the Honda or Tacoma being discussed in this thread: If you blow out 4 to 5 quarts of oil out around the spark plug then you are doing something wrong and need to surrender your drivers license.

 

OP,that doesn’t look like anything you gotta worry about. For all we know it could have been oil on the plug when it got installed originally.

 

I don't see a oil soaked plug.

 

I would think just going down the highway with no seal for an hour would do it. Seals don't have to fail linearly. Once they get old enough to rot or tear, it may go quick (or not).

 

Well in this case the oil under the valve cover is not under any pressure........................................................