Buick 2001 Century Owner's Manual page 235

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.
5-18
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.
4. Fill the radiator
with the proper
R
-
DEX COOL coolant
mixture, up to the base
of the filler neck. See
"Engine Coolant" in
the Index for more
information about the
proper coolant mixture.