Compressed Natural Gas Tank Replacement - Aft Tank

Compressed Natural Gas Tank Replacement - Aft Tank

Special Tools

J-45878 - Combustible Gas Detector

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Removal Procedure

1. Raise and properly support the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair.

2. Vent both aft fuel tanks if replacing one using the Compressed Natural Gas Tank Venting Service and Repair.

Warning:
Refer to Battery Disconnect Warning Service Precautions.


3. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection Battery Negative Cable Disconnection and Connection.





4. Close the manual tank valve(s).





5. Support tank assembly with aft axle tank cradle.

6. Remove the trailer hitch.

7. Disconnect the electrical connections.

Note:
Do Not remove "Live" pressure relief device (PRD) lines.

8. Disconnect the fuel line fittings.





9. Remove the bracket support nuts and lower aft axle tank assembly.

10. Disconnect the aft tank fuel lines.

11. Remove the aft tank retaining straps.

12. Carefully remove the aft tanks from the vehicle.

Installation Procedure

Caution:
Refer to Component Fastener Tightening Caution Component Fastener Tightening Caution.

1. The PRD and lines must be transferred to the new tank assembly before installation. Replace all O-rings with new seals and tighten fittings to 35 Nm (26 lb ft).

2. Raise the tank assembly up to the bolt locations.





3. Install the bracket support nuts. Tighten the mounting nuts to 79 Nm (60 lb ft).

4. Connect the fuel inlet line to the tank valve using a new O-ring. Lubricate the O-ring with petroleum jelly or equivalent. Tighten the fitting to 35 Nm (26 lb ft).





5. Connect the electrical connectors at the HPL.

6. Open the manual tank valve(s).

7. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection Battery Negative Cable Disconnection and Connection.

8. Pressurize the CNG fuel system by cycling the ignition ON and OFF several times.

9. Start the engine and use the J-45878 - detectorin order to inspect for CNG fuel system leaks at each serviced fitting.

10. Install the trailer hitch.

11. Install the fuel tank cover. Refer to Compressed Natural Gas Tank Cover Replacement - Aft Tank Compressed Natural Gas Tank Cover Replacement - Aft Tank.

12. Lower the vehicle