Pontiac 2003 Aztek Owner's Manual page 329

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.
Housing
BypassTube
3. After the engine cools, open the coolant air bleed
valves.
There are two bleed valves. One is located on the
thermostat housing. The other is located on the
thermostat bypass tube.
4. Fill the radiator with the proper DEX-COOL@
coolant mixture, up to the base of the filler
neck. See Engine Coolant on page 5-22 for more
information about the proper coolant mixture.
If you see a stream of coolant coming from an air
bleed valve, close the valve. Otherwise, close
the valves after the radiator is filled.
5. Rinse or wipe any spilled coolant from the engine
and the compartment.
5-34