Buick 1993 LeSabre Owner's Manual page 216

2. Then keep turning
the pressure cap,
but now push down
as you turn it.
Remove the
pressure cap.
I
3.
Fill the radiator
with the proper
mix, up to the base
of
the filler neck.
E
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.
214