2007 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 472

To remove the fuel cap, turn it slowly counterclockwise. It will require more effort to turn the fuel cap on the last turn as you loosen it. {CAUTION: If you spill fuel 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. If your vehicle is a dual fuel tank chassis cab model, and it runs out of fuel, refuel the front fuel tank first to ensure a quick restart. Be careful not to spill fuel. Do not top off or overfill the tank and wait a few seconds after you have finished pumping before removing the nozzle. Clean fuel from painted surfaces as soon as possible. See Washing Your Vehicle on page 591. When replacing the fuel cap, turn it clockwise until it clicks. It will require more effort to turn the fuel cap on the last turn as you tighten it. Make sure the cap is fully installed. 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 on page 256. The TIGHTEN FUEL CAP message will be displayed on the Driver Information Center (DIC) if the fuel cap is not properly installed. See DIC Warnings and Messages on page 267 for more information. 472