Chevrolet 2005 Equinox Owner's Manual page 264

1. You can remove the coolant surge tank pressure
cap when the cooling system, including the coolant
surge tank pressure cap and upper radiator
hose, is no longer hot. Turn the pressure cap slowly
counterclockwise about one-quarter of a turn. If
you hear a hiss, wait for that to stop. This will allow
any pressure still left to be vented out the
discharge hose.
2. Then keep turning the pressure cap slowly, and
remove it.
5-30
3. Fill the coolant surge tank with the proper
®
DEX-COOL coolant mixture, to the COLD
FILL line.