Engine oil on spark plug

[xyy]

Hey guys,

I just change my spark plug today for my little Aveo. For the first three plugs, they were very dry and clean, but for the last one which locates in the driver size, I found a lot of oil( smell and look like engine oil) on it. Why would this happen? Spark plug suppose to contact gasline not engine oil right? And Aveo is 2007 still pretty new.

 

[MarkM66]

Does is use oil between oil changes? If so, how much?

 

[xyy]

use oil? I change my oil on Feb.

 

[MarkM66]

Originally Posted By: xyy
use oil? I change my oil on Feb.


Not sure how I could word that any more simple.

After you fill the oil, and check it at a later time, is it lower?

 

[tenderloin]

Sometimes it is a simple as a valve cover gasket allowing oil to leak in where the spark plugs are located.

 

[xyy]

I get it. No, after three monthes the oil level still keep the same. I didnot notice any engine oil leak.

Today, I just notice the last plug is very wet covered by the oil which are so different from previous three plugs.

 

[xyy]

If the oil cover plug, the function would be affected right?
Originally Posted By: tenderloin
Sometimes it is a simple as a valve cover gasket allowing oil to leak in where the spark plugs are located.

 

[eljefino]

It sounds like you have wet engine oil, which compares to crusty burned oil from inside the combustion chamber.

I agree on the valve cover gasket idea.

This also allows you to lose 25 ccs of oil over the course of an oil change, way too small to notice having leaked using the dipstick, but plenty to dirty the plug.

 

[doitmyself]

We haven't established if the oil is on the tip/electrode side, or on the "top" porcelain side.

If the top of the plug is wet with oil, then the center gaskets or o-rings on the valve cover are leaking and need to be replaced. Some wetness on the plug won't cause problems. I suppose you can keep an eye on it and when oil starts pooling in the well, then you should definitely take action. Either way, plan to have it fixed some time in the future.

 

[ChiTDI]

Great schematic there, doitmyself.
If there are metal tubes above the spark plug gaskets, they too can crack and provide a leak source.
I'm not familiar with the Aveo engine design.

 

[eljefino]

If there's oil on top of the spark plug, it will of course dribble down around the threads and tip when removed from the engine.