2000 Chevy Astro gasket leak?

I recently bought this Astro and was told that the oil pump had failed and it might need an intake manifold gasket. When I took out the oil pan to change the oil pump, the oil had already been drained, but there was a little left and it was obvious there was some coolant leaked in there from the engine. Can a manifold gasket leak coolant, or is it the head gasket that is probably leaking the coolant? I am just unsure as to which gaskets needs replacing, thanks.