[skidlids]

A strong Anti Freeze Mix and make sure you run it around the system for a while, As its also a corrosion inhibitor and will help protect your water cooling components.
Come the First meeting of the year on a couple of occasions I would run the bike up the day before leaving home to check all was OK, then drain the system and load up the bike.
Take to scrutineering with a dry system and then fill the system prior to practice.