head gasket or cracks?

The burning of gasoline produces water vapor so that may be all it is. When it condenses inside the exhaust system, it drips out any hole it can find or out the tailpipe. If you're losing coolant, you'll have to find the cause. Have the system pressure tested to find any internal (or external) leaks. If you have a good mix of antifreeze, you can usually smell it in the exhaust fumes if you're "burning " it.