Oldsmobile INTRIGUE 2000 Owner's Manual page 227

Turn the pressure cap slowly counterclockwise (left)
-
about one quarter turn and then stop.
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.
5-18
1. You can remove
the coolant surge
tank pressure cap
when the cooling
system, including
the coolant surge
tank pressure cap
and upper radiator
hose, is no
longer hot.
2. Then keep turning the pressure cap slowly, and
remove it.