Why is machine blowing white smoke. what could happen while it is parke overnight?

worked trac hoe then parked it over night . machine would not start next day. started it with either now blows white smoke and has no power.i have changed lift pump,injector pump and injectors. checked timing still blows whit smoke.|||White smoke isn't white smoke it's steam. Blown head gasket, cracked head, something along those lines. It's coolant you're looking at.