Pontiac 1999 Firebird Owner's Manual page 229

2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Don't spill coolant on a hot engine.
3. After the engine cools, open the coolant
air bleed valve.
There is one bleed valve. It is located on the
thermostat housing.
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