Mike Sigmond

So whats a good explanation for oil on the plug threads, My engine is very clean and I havent spilled any oil anyware. I feel I have a leaking manifold gasket, All my cylinders are between 100-110 PSI compression, Coolant is clean, oil is clean, Anyone have any input on this one? This may explain my hesitation on heavy acceloration if the Intake manifold gasket(s) is blown. Could this be from the seafoam treatment as well? breaking down the carbon and its working its way up the plug threads?

Pic of oiled plug attached, these plugs are only 3 weeks old, I put new AC DELCO iridium's in yesterday. I have learned that Bosch is crap for Chevys. Time to leave the plugs alone now for about 100,000 miles.

Koffietje

Do you have to refill oil after a certain amount of miles? If not, then the substance on your plugs isnt oil.
(Can you take a picture of the elektrode as well? If that elektrode is white, then the black isnt oil but gas).
Gas has a certain substance in it, that can give the same result on your spark plugs. Usually its because the gas isnt burned properly in your engine.

Plugs have a certain heat range. Could be yours is too low. Or you're not using the correct gas?

NGK plugs are good for american cars.

Maybe this can help allthough the symptoms you describe sound to me as if you've got an oil leak)

http://www.aa1car.com/library/reading_spark_plugs.jpg

Mike Sigmond

No I am not loosing any oil, I think your right , its not oil , its too thin, it had the viscosity of gas. I did use sea foam in the intake and tank, Hopefully its just gunk & carbon breaking down. I am loosing coolant though, about a quart every 3 months. My hesitations got to be the coolant leaking into the intake system since there is no visible leaks. Its fine if I drive it easy, but no power if I need it. Maybe it leaks only under high pressure( full throttle) or vacuum situations.

mudmaniac

I wonder if the coolant is a seperate issue, I have the TBI unlike you, but I had that same issue when I had too large of injectors installed. I could literaly go to the tail pipes and smell the un burnt fuel.
Could it be possible that a temp sensor is failing and therefor running rich and overheating without you being aware?
I imagine that would throw a code.

Mike Sigmond

No codes but I am not ruleing anything out , it could be a sensor that isnt out of range yet but is failing. I would take it to the dealer to get it diagnosed but I dont have the $ or the time for a while.

Here is a few pics of my version of the 6.0 with the cover off for any reference

Mike Sigmond

I guess what throws me off is that only 4 out of the 8 plugs were like that. 2 on the right side and 2 on the left.

mudmaniac

I assume it is a dual plane intake, were the cylinders all on the same plane?

Mike Sigmond

Yes, it was the front 2 cyl on each side.

in2pro

Active fuel management? 4cyl mode?

Mike Sigmond

I wish I had that, unfortunately not. I am pretty sure it was the sea foam I puored in the vacuum line that the PCV connects to. The hesitation/power loss problem was happening before this , the plugs I took out a few weeks ago did not look like that, just normally worn a little.