head gasket or not

If your looking for an external leak use a coolant pressure tester/ if your looking for a head/ head gasket issue, have a chemical test done to look for combustion gases in coolant.

if you have white smoke and see coolant in the oil and see oil around the front manifold gasket can it be a manifold gasket leak other then a head gasket leak,and can you have white smoke if manifold gasket is leaking?

Yes, if the upper intake plenum (black plastic) on this 3.8 is leaking, it will flood the intake runners with coolant and burn it, you will see smoke, it usaully hydro locks the engine,

what happen when manifold gasket is bad?

will that be white smoke too?

Yes, white, almost sweet smelling smoke