Chevrolet 2003 Impala Owner's Manual page 261

1
If you get fuel on yourself and then sometnmg
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.
While refueling, let the fuel cap hang by the tether
below the fuel opening.
To remove the fuel cap, turn it slowly to the left
(counterclockwise).
Be careful not to spill fuel. Clean fuel from painted
surfaces as soon as possible. See Cleaning the Outside
of Your Vehicle on page 5-86. When filling the tank
do not overfill by squeezing in much more fuel after the
pump shuts off.
When you put the fuel 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 lndicator Lamp on
page 3-36.