Pontiac 2001 Montana Owner's Manual page 353

While refueling, let the cap hang by the tether as shown.
To remove the cap, turn it slowly to the left
(counterclockwise). The cap has a spring in it; if you let
go of the cap too soon, it will spring back to the right.
CAUTION:
If you get gasoline on yourself and then
something ignites it, you could be badly burned.
Gasoline can spray out on you if you open the
fuel filler cap too quickly. This spray can happen
if your tank is nearly full, and is more likely
in hot weather. Open the fuel filler cap slowly
and wait for any "hiss" noise to stop. Then
unscrew the cap all the way.
Be careful not to spill gasoline. Clean gasoline from
painted surfaces as soon as possible. See "Cleaning
the Outside of Your Vehicle" in the Index.
When you put the cap back on, turn it to the right
(clockwise) until you hear a clicking sound. Make sure
you fully install the cap. The diagnostic system can
determine if the fuel cap has been left off or improperly
installed. This would allow fuel to evaporate into the
atmosphere. See "Malfunction Indicator Lamp" in
the Index.
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