GMC 1998 Safari Owner's Manual page 290

Adding Coolant
If you need more coolant,
add the proper
DEX-COOL@
coolant mixture at the coolant recovery tank.
Ihning the radiator pressure cap when the
engine and radiator are hot can allow steam and
scaldingjiquids to blow out and burn you badly.
With the coolant recovery tank, you will almost
never have to add coolant at the radiator,
Never turn the radiator pressure cap
--
even a
little
--
when the engine and radiator are hot.
Add coolant mixture at the recovery tank, but be careful
not to spill it.
Radiator Pressure Cap
NOTICE:
Y o n r
ra&#or cap is
B
15 psi (IO5 kPa)
presmm-type
cap and must be
tightly installed
to
prevent coolant loss
and podble engine
damage
from overheating.
Be
sure the arrows on the cap
line up with the over&law tube an
the
radiator
mer neck.