Agreed. white smoke signifies coolant being burned inside the engine. it should not mix. it may be any of the following or a combination of:

Warped head
Poor gasket installation
incorrect torque specs or torque sequence
old/poor fuel


Check coolant levels and check for air. also check the oil for coolant. if oil is getting into the combustion chamber, it could be geting other places which could lead to bearing or ring failure.