burning oil, maybe?

[yosh18981898]

I changed my spark plugs and noticed that the middle cylider on the drivers side spark plug was covered in oily deposits, I changed all the plugs and checked the new plugs a month later and that one plug was covered in oily deposits again. If I remember right, this is a sign of an internal oil leak causing oil burning. However, the engine only has 95,000 (not much for a 4.0) and runs like a top. It starts easily, idles smoothly, has a great throttle response, pulls hard, strong, and steady at all RPMs, and sounds good too. There is NO black, blue, or white exhaust. Any ideas why there is oil on the one spark plug?

 

[mrboyle]

Do you have to add oil between changes? From your desctipion it sounds like you may have a valve guide going bad. The only way to tell is to start with a leakdown test. This will eliminate any problems with the bottom end. Then its up to you weither you want to run the engine until the problem becomes bad enough to justify pulling the heads and having a valve job done or do it now.

 

[NickSD]

Saw this in a search.

I have the same thing in cyl. #6. All other plugs look great. Could the oil be coming in through a leak in the intake gasket? Do these engines typically start to wear out one guide before the others go? I would have expected the guides to generally wear out together. My rig gets about 1000 miles per quart but runs well. It sounds like I do have some detonation from #6.