Nothing Nothing
there might be a leak some where in a coolant line. or maybe you have a leak in your radiator.
Volkswagen or any other vehicle shouldn't use any antifreeze. If any car is using antifreeze something is wrong.
probably a blown head gasket.
if you run your engine without antifreeze your car will overheat and ruin the engine.
crack the engine block and oil mixes with water or antifreeze.
It will overheat because the water is needed to circulate/transfer the heat.
If you have water instead of antifreeze in your cooling system, it will freeze! You won't be able to start the car, because the engine is connected to the water pump (which won't be able to move). If you have nothing in your cooling system (no water, no antifreeze, nothing else), then you need your head checked. Your car won't start either.
Probably a blown head gasket. Get a technician to look at it. If it is, it will be a major ordeal.
Probably not. If the water pump is gone it would be a separate issue
Then the headlights won't work.
Ask this question again specifying what the car is.
the heater core may be plugged up