If you need to store the cooling system open, as when the radiator is removed, here is a tip to help prevent evaporation and rust from setting in.

• Leave the upper and lower radiator hoses installed.
  
  
• Grab some plastic wrap and aluminum foil from the kitchen.
  
  
• Place a small piece of plastic wrap around the end of a radiator hose, followed by a piece of aluminum foil, and another piece of plastic wrap on top.
  
  
• Slide a hose clamp over the whole thing and snug down a bit.