Chevrolet 1997 Corvette Owner's Manual page 232

4. With the coolant surge tank pressure cap off, start the
engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the
engine fans.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mix to the coolant surge tank
until the level reaches the FULL COLD mark.
5. Then replace the pressure cap. Be sure the pressure
cap is tight.
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