Oldsmobile 2002 Aurora - Manual (Page 243)

5-17
1. Park the vehicle on a level surface. 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. 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.
2. Then keep turning the
pressure cap slowly, and
remove it.
3. Then fill the coolant
surge tank with the
proper mixture, to the
base of the filler neck.