[sglemans]

Just noticed a pool of antifreeze in the front curved section of the intake manifold, as seen in the pic behind the water pump. Dont see any leaks anywhere. Anyone have any ideas? Must be a common issue, since my last Pontiac had the same problem (sold it before it was fixed)

[A390GT]

The thermostat housing upper rad hose or the water pump to intake seal could be weeping.
I’d try slightly tightening the thermostat housing gasket bolts and upper radiator hose clamps first.

The intake to water pump is more involved

John-

[tom s]

From the pic it looks like the thermo gasket or hose has been weeping,the intake to front cover looks tight.Tom

[goatlessJr.]

I had the same issue on my engine. The problem went away with a new set of intake manifold gaskets after doing a larger project.

[Ben M.]

It's almost always the intake to timing cover bypass. That rubber o-ring gets hard and can't handle the pressure of the system, tightening the intake to timing cover bolt won't help. It won't look like it's leaking because of the fan, but that spot is 9 out of 10 times the bypass. It's an easy job to fix.

[sglemans]

I will check the thermo cover bolts and the upper hose clamps for looseness.

It's interesting that it only leaks after sitting, when you drive it apparently dries up. Then it comes back after sitting for a few days.