1998 GMC Suburban Owner's Manual - Page 299

To remove the cap, turn it slowly to the left (counterclockwise). I If you get gasoline yourself and then on something ignites it, you could bebadly burned. Gasoline can spray outon you if you open the fuel filler cap too quickly. This spray can happen if your tankis nearly full, and is more likely in hot weather. Open thefuel filler capslowly and wait for any"hiss" noise to stop. Then unscrew the capall the way. ~ When you put the cap back on, turn it tothe 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 or improperly off installed. Thiswould allow fuel to evaporate into the atmosphere. See"Malfunction Indicator Lamp" in the Index. NOTICE: If you need a new cap, be sure to get the right type. Your dealer canget onefor you. If you get the wrong type, it may not fit properly. This may cause your malfunction indicator lamp to light and yourfuel tank andemissions system may be damaged. See "Malfunction Indicator Lamp" in the Index. 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. 6-7