2012 Yukon, 5.3, shop says oil leak in head gasket causing oily plugs

[201125004x4Sub]

I think the AFM/DOD is still functioning. The #7 plug has been fouling for so long now. Car has like 130k-plus miles on it.

i have changed the valve cover/PVC and I even swapped out the valve stem seals on #7. That was such an annoying job, the two I removed did seem like the rubber was very hard and the opening for the valve was worn.

i finally took it to a shop. He said the head gasket is leaking oil to the plug.

I have not heard of oil getting to the plug from the head gasket.

Have you guys heard of this?

thank you

 

[j91z28d1]

there's a thread around here somewhere about oil control rings getting gunked up and stuck allowing for bad oil consumption. it was a back cyl, but I don't really. probably 7 though since it seems it's always the driver's side

I think it was @donjetman thread? maybe try that fix?

 

[mikez71]

Apparently there is no oil feed going through the headgasket..
And I don't think it would leak from the crankcase portion..

 

[strutaeng]

Huh? Never heard of that. Head gasket seals heads to the block. So combustion gases and it does also seal the coolant passages.

 

[j91z28d1]

oh and catch can.. they seems to be a must. mine I wouldn't even consider using oil being an issue, since i never notice is low or on the plugs. but added a catch can and it has a decent amount in it every oil change.

kinda wild


there's threads around here on those too. the 30$ Amazon ones seem fine.

 

[201125004x4Sub]

Hello! Hey, is it possible that the oil that is draining back down to the block in the lower corners could be leaking into the cylinder somehow?

Thanx.

 

[j91z28d1]

for oil to get into the cylinder thru the head gasket. air could get back thru during compression and firing. unless you have tons of blow by with it running. pull the oil cap and see if it's puffing like a freight train.

I can't think of any way oil can get in and air wouldn't get out. this is most likely oil getting by the rings, or somehow being poured or sucked down the intake port.

 

[Dustin Jackson]

piston rings could be letting oil by, maybe do a compression test

 

[donjetman]

piston rings or valve stem seals