2004 Buick Century Owner's 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. 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. The other is located on the thermostat bypass tube. 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