2005 1500 5.3 Vortec 4 Wheel Dr. Silverado Z71

Subject:
Major OIL leak intake manifold/head gasket on 2005 5.3 Z71

Hello,
I posted a few times here, but nothing like this. My engine has been leaking oil for a while now, but recently have been using more oil than ever.

It’s not leaking by the oil pressure switch.
Oil is spraying under the intake manifold on the valley plate between the heads

All spark plugs are burning clean but a little hot, engine idle is smooth and engine runs great.
We loose a quart of oil every 2 weeks.
Took off intake manifold and saw valley plate and the back knock sensor was flooded with oil.
Could this be a head gasket or cracked cylinder head?
Remember the motor runs real smooth and strong.........

Now I opened up the hood to see oil all over the top of engine. Could this be a cracked head? What are the symptoms?
Thank you!

 

I don't think it's a head gasket or cracked cyclinder head since you are not losing antifreeze and not blowing anything unusual out the tail pipe and as you say the engine runs smooth. My guess is that maybe a valve cover gasket is bad and pressure is blowing oil thru it. Another guess is it could be a crack in the engine block where an oil passage is.

 

There are rubber gaskets that go under the plate where the knock sensors are. I would replace the plate gasket and the 2 rubber gaskets. You have to remove the knock sensors the remove the plate. Rubber gaskets might be hard and cracked??