Fuel Pipe O-Rings
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.
O-rings seal the threaded connections in the fuel system. Fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.