Oil on sparkplug #1

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rustyxl

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Recently bought a 2013 yukon 5.3 and there is oil on the number 1 spark plug, there are no check engine light on and the oil pressure stays a hair under 40 at idle and raises above 40 when accelerating what could be the issue?
 

Charlie207

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Is it possible that oil is leaking from above (valve cover, etc.) the spark plug and simply dripping into the cavity where the spark plug sits?
That was my guess. It'd be hard for oil to travel the other direction, from inside the cylinder, and out, without a lot more indication that something was wrong.
 

j91z28d1

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I've have actually taken out a plug before, not on my yukon but other stuff that threads were full of oil, plug was clean ish for a old plug inside and zero oil outside from valve cover or showing on the head.


I can't explain it, but I've seen it. either way, make sure you torque the new plugs to spec and as long as they don't oil foul inside the cyl. I've never seen it be an issue.
 

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