Lumina V6-3.8L VIN K (1998)
Fuel Return Line: Description and Operation
FUEL FEED AND RETURN PIPES / HOSES
The fuel feed and fuel return pipes carry fuel from the fuel sender assembly to the fuel injection system and back to the fuel sender assembly.
NYLON FUEL PIPES
Nylon fuel pipes are designed to perform the same job as the steel or rubber fuel pipes they replace. Nylon pipes are constructed to withstand
maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There are two sizes used: 3 / 8" ID for the fuel feed, and 5
/ 16" ID for the fuel return.
Pipes that are exposed to chafing, high temperature or vibration are protected with heat resistant rubber hose and / or corrugated plastic conduit.
Nylon fuel pipes are somewhat flexible and can be formed around gradual turns. However, if forced into sharp bends, nylon pipes will kink and
restrict fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Special care should be
taken when working on a vehicle with nylon fuel pipes.
WARNING: To Reduce the Risk of Fire and Personal Injury:
Always cover nylon fuel pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher then
115° C (239° F) for more than one hour, or more than 90° C (194° F) for any extended period.
Take care not to nick or scratch the nylon fuel pipes. If damaged, they must be replaced.
QUICK-CONNECT FITTINGS
Quick-connect type fittings provide a simplified means of installing and connecting fuel system components. Depending on the vehicle model,
there are two types of quick-connect fittings, each used at different locations in the fuel system. Each type of quick-connect fitting consists of a
unique female connector and a compatible male fuel pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking
tabs or fingers hold the quick-connect fittings together.
FUEL PIPE O-RINGS
Fuel feed and return pipe threaded connections at the fuel rail and fuel filter are sealed with replaceable O-ring seals. These O-rings seals are made
of special material, and should only be serviced with the correct service part.
