I'm gonna second the blown head gasket. I concur that it's an alternator/battery issue originally. Alternators can take out batteries when they fail. It's also possible (unlikely, but possible) that you have a grounding issue causing power drain.

Coolant issue is hard to diagnose. Could be a thermostat. Could be a head gasket. Could be a connected problem which chained from one thing to another. Could be an old/clogged/bad radiator. Could be fan clutch needs replaced. LOTS of things could contribute.

I STILL don't know what caused the head gasket in my VX to fail. I did get virtually every other component replaced though--and I haven't had a temp problem in 2 years.