I changed my spark plugs and found oil on one or 2 of the plugs in my 5.9 v8 magnum gas. I see a million videos about how to replace the spark plug tubes seals and how important it is to an engines health.. all of the videos are for spark plugs that install through the valve covers. I’m trying to figure out what I need to do to get to & replace the spark plug seals on my engine if the spark plugs install under valve covers.

 

There aren't any on the 5.9. If you are getting oil on the plugs, it is more likely coming from the valve cover.