Chevrolet 2006 Corvette Owner's Manual page 315

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
cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level stabilizes at the FULL COLD mark
on the coolant surge tank.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Check the level in the surge tank when the system
has cooled down. If the coolant is not at the
proper level, repeat Steps 1 through 4, then reinstall
the pressure cap. If the coolant is not at the
proper level when the system cools down again,
see your dealer.
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