4.5 Use distilled water for the cooling system
Tap water contains many minerals that will eat the aluminum of the blocks
and heads, causing not only corrosion but a buildup of deposits in the
coolant passages, the radiator, and the thermostat. Distilled water
and a proper percentage of antifreeze/coolant (30% for winters below
3 degrees F, 50% for winters above 3 degrees F) will extend the life
of the engine and ensure maximum cooling efficiency.
