Oldsmobile 1995 88 Owner's Manual page 214

6. Start the engine
and let it run until
you can feel the
upper radiator hose
getting hot. Watch
out for the engine
fans.
8. Then replace the
pressure cap.
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.
At
any
time during this procedure if coolant begins
to flow out of the filler neck, reinstall the pressure
cap. Be sure the mows on the pressure cap line up
like this.
5-18