Basically just get the cooling system up to pressure and check for any coolant leaks.(cooling system pressure tester) Also watch the pressure gauge and make sure it doesn't drop in case it is internal. Most likely it's your intake manifold gaskets or a radiator hose since I'm not sure the coolant elbows would even be able to make it to an exhaust manifold. They should be replaced no matter what since they're cheap and will go bad soon anyway if not already. Look real good around the whole intake manifold and feel both radiator hoses and both heater hoses. If you saw a lot of smoke it can't be too hard to find the leak.
