Tear Down Question

[JB601]

I request the advice of any one who may have recommendation:
1996 Monte Carlo Z34; 3.4 DOHC; 134,000

I have to tear down my top end to fix the dreaded O-Ring oil leak or at least I hope that is what it is. I have seen pics of a tear down shows were the o ring leak is located. I was under the impression that is was on the backside of the motor next to the fire wall (back meaning: standing at the front bumper looking toward the windshield) Then I was told that the o ring is located on the rear of the engine (rear meaning: The right side/ driver's side of the enging standing at the front bumper) Were exactly is this thing?

Second: I broke down and purchased the intake gasket set kit from NAPA (intake and plenum gaskets and another gasket that I really don't know were it goes yet). I went ahead purchased a 180 degree thermostat and gasket so I can change it out while I have the top end torn down. Got spark plugs even though they aren't bad, might as well change them out while I have the plenum off. Is there anything else I should check out or replace while I have the top end torn down?

Third: I have read thru the post and manuals, but exactly how do you bleed the air out of the cooling system. I changed the coolant out in the fall. I see the knob on the top of the thermostat housing, but what's the best way of doing it? Just open it and wait till all the air stop and the coolant starts spitting out?

Fourth: Is there any other known locations of oil leaks that would leak on the back side of the engine over on the driver's side?

One last item: My drivers side window gets a lil jammed on the way up. You have to physically grab the windows and slide it back and it will roll the rest of the way up. How in the way to you adjust the track? I took the door panel off and really didn't see how the thing tracks. Every month or so I spray silicone spray in the window jam (the jam right by the outside mirror). And it slide beautifully until it needs more spray.