Important: The fuel rail for the 5.3L regular production option (RPO) L59 (VIN Z) is compatible with fuel that has a composition of up to 85 percent Ethanol (E85). Because of this, the fuel rail will be serviced as an entire assembly, that includes both the left and right rail assemblies and the crossover pipe rail.

1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
2. Disconnect the fuel feed (1) and the fuel return (2) pipes from the fuel rail.



3. Remove the fuel return pipe attaching screw (3) and the fuel return pipe retainer (2).
4. Remove the fuel return pipe (1).
5. Remove and discard the fuel return pipe O-ring (6).
6. Remove the fuel pressure connection core assembly (24) from the crossover pipe rail (25).
7. Remove the retaining clip attaching screw (22) and the crossover fuel pipe retainer clip (21).
8. Remove the retaining clip attaching screw (4) and the crossover fuel pipe retainer clip (5).
9. Remove the crossover pipe rail assembly (25) from the left hand rail assembly (14) and the right hand rail assembly (15).
10. Remove and discard the crossover fuel pipe O-rings (7, 20).

1. Lubricate the NEW crossover fuel pipe O-rings (7, 20) with clean engine oil.
2. Install the NEW crossover fuel pipe O-rings (7, 20) onto the crossover pipe rail assembly (25).

Notice: Refer to Fastener Notice in the Preface section.

3. Install the crossover pipe rail assembly (25) to the left hand rail assembly (14) and the right hand rail assembly (15).

Important: When installing the retaining clip attaching screws for the crossover pipe, always start them by hand. This will prevent consequent stripping of the threads in the rail.

4. Install the crossover fuel pipe retainer clip (21). Loosely install the retaining clip attaching screw (22).
5. Lubricate the NEW fuel return pipe O-ring (6) with clean engine oil.
6. Install the NEW fuel return pipe O-ring (6) on the fuel return pipe (1).
7. Install the fuel return pipe (1).
8. Install the fuel return pipe retainer (2). Loosely install the fuel return pipe attaching screw (3).

Important: When installing the retaining clip attaching screws for the crossover pipe, always start them by hand. This will prevent consequent stripping of the threads in the rail.

9. Install the crossover fuel pipe retainer clip (5). Loosely install the retaining clip attaching screw (4).

Tighten

1. Tighten the crossover fuel pipe retainer clip attaching screws to 3.8 N·m (34 lb in).
2. Tighten the fuel return pipe attaching screw to 5 N·m (44 lb in).
10. Install the fuel pressure connection core assembly (24) to the crossover pipe rail assembly (25).



11. Connect the fuel return (2) and fuel feed (1) pipes to the fuel rail.
12. Tighten the fuel fill cap.
13. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
14. Use the following procedure in order to inspect for leaks:

14.1.

Turn ON the ignition, with the engine OFF, for 2 seconds.

14.2.

Turn OFF the ignition for 10 seconds.

14.3.

Turn ON the ignition, with the engine OFF.

14.4.

Inspect for fuel leaks.

15. Install the fuel pressure connection cap.