Thanks for that. But I can't do a leak down test.

 

The shop has basically given up. They have seen it smoke and have no idea what is causing the problem. They did a compression test and the numbers were within spec.

The other day I removed the air filter, the air plenum and throttle body. The inside of the intake manifold is wet with oil. I then blew compressed air down through the hole in the right side (the cars right side) of the cam cover. That's the hole that draws filtered air into the engine. I could feel air coming out of the left side hole. So the baffles inside the cam cover are not plugged. My next step will be to remove the vacuum hose from the left side hole and plug the line. I will then run a hose from the hole down the side of the engine.

I think for some reason the vacuum line is pulling too much vacuum in the cam cover. The shop did say that maybe the baffles inside the cam cover have come loose or fallen off. Because I have never see the inside of the cover I have no idea what's in there. And remember, it didn't do this before they removed the head.

I'll update when I have some results.

 

There has been threads in the past about the baffles inside dislodging. In fact I think if memory serves me there is a YouTube video covering such stuff?

 

I have searched and searched and d?searched and can't find any video regarding baffles coming loose. The question now is if they do come loose can they reattached?
It's been a busy few days and I have not had time to work on the Hummer. My next step is to remove the vacuum line that comes off of the intake manifold and plug it off. Then vent the cover to the atmosphere. If that stops the smoking, which is still horrible, then the problem must be the baffles.

Thanks again for your help.

 

Well, disconnecting and plugging the vacuum hose and venting the cam cover to the atmosphere has stopped the smoking. So it seems as though the problem must be those baffles. The hose that vents to the atmosphere has no vapors or oil coming out of it and there are no new oil leaks. The Hummer starts and runs just fine.

I will make no further changes and do not plan on removing the cam cover.

Thanks to all for your comments.
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Until you get the CEL for that.

 

What is a CEL?

 

Check Engine Light

 

Ohhhh! That. I can ignore that. And then clear the code before it goes in for inspection.