Buick 2003 Century Owner's Manual page 225

While refueling, let the fuel cap hang by the tether
below the fuel fill opening.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). The fuel cap has a spring in it;
if you let go of the cap too soon, it will spring back to
the right.
If you get fuel on yourself and then something
ignites it, you could be badly burned. Fuel can
spray out on you if you open the fuel cap too
quickly. This spray can happen if your tank is
nearly full, and is more likely in hot weather.
Open the fuel cap slowly and wait for any
"hiss" noise to stop. Then unscrew the cap all
the way.
Be careful not to spill fuel. Clean fuel from painted
surfaces as soon as possible. See
Cleaning the Outside
of Your
Vehicle
on
page
5-82. When filling the tank
do not overfill by squeezing in much more fuel after the
pump shuts off.
5-8