Buick 2004 Century - Manual (Page 245)

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 a stream of coolant is 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.
5-33