Chevrolet 2002 Prizm Owner's Manual page 211

6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fans.
7. By this time, the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper coolant mixture through the
filler neck until the level reaches the base of the
filler neck.
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8. Then replace the pressure cap. At any time during
this procedure if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the ears
on the pressure cap are in line with the vent tube.