Oil on Glow Plug

[eand28]

Changed all 8 glow plugs on my lly and all of them looked fine except for the one on cylinder 3. When I pulled it out, it was covered in oil near the tip. I assumed at the time it was from the oil leak I have from the egr valve, but after further reading online, I feel like I need to test the compression. Balance rates were fine last time I looked at them. Truck seems to run fine. Pictures of suspect glow plug and all 8 below.

 

[2004LB7]

Valve guide

 

[Chevy1925]

Valve guide

Better not be. Hed have a heck of a noise comin from that cylinder like a blown injector copper



Looks like oil leak down from your oil leak. That leak will kill the glow plug quicker than the others will die

Also be sure you put true acdelco g9’s in there

 

[gmduramax]

Is that oil or fuel leaking down the valve cover?

 

[eand28]

Is that oil or fuel leaking down the valve cover?

I’m pretty sure it’s oil from the egr valve but the one injector is right below it and it’s an oily mess

 

[eand28]

Better not be. Hed have a heck of a noise comin from that cylinder like a blown injector copper



Looks like oil leak down from your oil leak. That leak will kill the glow plug quicker than the others will die

Also be sure you put true acdelco g9’s in there

Yup. Put oem ones back in. The glow plugs seal against the head where the tip of the plug enters the combustion chamber correct?

 

[eand28]

Can kinda see the oil goes up the head a bit. I guess it could maybe be something injector related since the cylinder 1 injector line is covered in oil but I think it’s from the egr

 

[Bdsankey]

To me it looks like residual oil from the leak that found it's way down to the glow plug hole. Fix the oil leak or as James said it'll kill that glow plug quicker than the others.

Also as James said, ONLY use genuine GM/ACDelco 9G glow plugs. Do not use anything aftermarket. RockAuto tends to be the cheapest place for these I've found (my local area that is).