Chevrolet 2003 Astro Owner's Manual page 255

3. Fill the radiator with the proper DEX-COOL@
coolant mixture, up to the base of the filler
neck. See Engine Coolant on page 5-28 for more
information about the proper coolant mixture.
4. Then fill the coolant recovery tank to the ADD mark.
5. Put the cap back on the coolant recovery tank,
but leave the pressure cap off.
5-38