Buick PARKAVENUE 1994 Manual page 215

4. Then fill the coolant recovery tank to "FULL COLD."
5. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.
6.
Start the engine and
let it run until you
can feel the upper
radiator hose
getting hot. Watch
out for the engine
fans.
7 .
By this time the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper mix through the filler neck until
the level reaches the base of the filler neck.