1998 Chevrolet Astro Owner's Manual - Page 268

The fuel cap is behind a hingeddoor on the driver's side of your vehicle. A CAUTION: 1 If you get gasoline on yourself and then something ignites it, could be badly burned. you Gasoline can spray out you if you open the on fuel filler cap too quickly. This spray can happen if your tankis 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. While refueling, place the cap inthe holder on the fuel filler door. When you put the cap back on, turnit to the right (clockwise) until you hear a clicking sound. Make sure you fully installthe 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. 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.