3.1L chevy vin M ohv engine?

I have coolant loss that is draining down to the bottom of the oil pan. after some drives when put the car in park the engines idle speed goes low and white smoke comes out the exhaust for about 5 seconds until idle speed rebounds and then the smoke stops. There is no fluid contamination "oil in coolant or coolant in oil" I know the intake gaskets are often a problem on this engine. I have no over heating problems but sometimes there is a knock sound "more like exhaust leak" when the coolant is low. I will probably do intake and head gaskets at the same time since its already so torn down from the intake work. My question is can the head gasket leak and cause these symptoms or is it more likely just the lower intake manifold gasket. I do not think the tick is a knock because it is more rare and seldom happens unless the fluid is low making me think both gaskets are bad but still no over heating or fluid contamination. But coolant is leaking on the ground and some is getting in the cylinders.