My overflow bottle is low (dry!). I obviously MUST add something immediately. Can it just be tap water? Soft tap water or hard water? Distilled? Do I need to add special chemicals because of the aluminum engine like the Northstar engine requires? (so I hear) I probably should do a flush since the most recent one may have been 97 when a previous owner had a lot of work done at Houston. So in the mean time... water? --------- I read this somewhere: "most experts agree that the end of the world will come by accident, most likely. That's where we come in; we're Computer Experts, we make accidents."