1998 Buick Century Owner's Manual - Page 243

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" in the Index for more information about theproper coolant mixture.) If you see a stream of coolant coming from an air bleed valve, close the valve. Otherwise, closethe valves after the radiator is filled. 5 . Rinse or wipe any spilled coolant from the engine and the compartment. 5-23