there three possible answers. If the white smoke only appears for a few minutes after starting the car, if is only condensation and will not be harmful. if the smoke is light blue or grayish blue white, this indicates worn piston rings and you are seeing burning oil. this smoke will hang in the air behind the car. if the smoke is definitely white and continues after the engine heats up, you probably have a bad head gasket or a cracked head. I would check the oil. If it contains milky white substance, that is water in the oil from the head gasket or cracked head. one final test, when the engine is cool, take the radior cap off, make sure the radiator if full, crank the engine. if water shoots from the radiator, this indicates again a bad head gasket or cracked head.
