Finally mined my way down to the lower intake manifold on the 3.4L engine in my daughter's 2000 Alero today. (By the way whoever out there said that he can do this whole gasket change job in five hours has my utmost admiration and respect.)
What took me by complete surprise after the manifold was off was the minor pitting that was present in the gasket surfaces of both the head and the manifold around the coolant passages.
Is this pitting the cause of the notorious leakage on these engines or is it the gasket itself that fails?
Could it be that some component or combination thereof in the gasket material doesn't get along well with aluminum in the presence of coolant with heat and gasket clamping stress factored in? I'm not up on the various electromotive series present in this part of the engine. It would be interesting to find out what metals can coax aluminum to sacrifice itself for the existing conditions.
What theories do you have?