Chevrolet 2012 Corvette Owner's Manual page 306

WARNING (Continued)
Never turn the cap when the
cooling system, including the
coolant surge tank pressure cap,
is hot. Wait for the cooling system
and coolant surge tank pressure
cap to cool if you ever have to
turn the pressure cap.
If coolant is needed, add the proper
DEX-COOL coolant mixture directly
to the surge tank, but be sure the
cooling system is cool before this
is done.
1. When the cooling system,
including the coolant surge tank
pressure cap and upper radiator
hose, is no longer hot, remove
the pressure cap.
Turn the pressure cap slowly
counterclockwise about
one-quarter turn and then stop.
If a hiss is heard, wait for that to
stop. A hiss means there is still
some pressure left.
2. Keep turning the pressure cap
slowly, and remove it.
Vehicle Care
3. Fill the coolant surge tank with
the proper DEX-COOL coolant
mixture until the level inside
stabilizes at the FULL COLD
mark on the front of the
surge tank.
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