GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Controls - 6.6L (LB7) 🢒 Fuel Return Pipe Connector Replacement

Removal Procedure
  1. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.

    3. Object Number: 664851 Size: SH
  3. Remove the right turbo charged air outlet hose.

    4. Object Number: 664853 Size: SH
  4. Remove the left turbo charged air outlet hose.
  5. Remove the engine wiring harness. Refer to Engine Wiring Harness Assembly Replacement .

    6. Object Number: 660425 Size: SH
  6. Remove the heater pipe assembly.

    7. Object Number: 791983 Size: SH
  7. Remove the fuel feed line (1).
  8. Remove the generator. Refer to Generator Replacement in Engine Electrical.

    9. Object Number: 791986 Size: SH
  9. Remove the fuel hoses from fuel feed block (1).
  10. Remove the fuel feed block bolt and nut and remove feed block (1).
  11. Remove the fuel leak-off block pipe to cylinder head bolt.
  12. Remove the fuel leaf-off block (2).

Installation Procedure

    Object Number: 791986 Size: SH

    Important: Always install new fuel line gaskets when servicing fuel lines.

  1. Install the fuel leaf-off block (2).

    2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the fuel leak-off block pipe to cylinder head bolt.

    3. Tighten
    Tighten the leak-off block pipe bolt to 15 N·m (11 lb ft).

  3. Install the fuel feed block (1) and bolt and nut.

    4. Tighten
    Tighten the nut and bolt to 25 N·m (18 lb ft).

  4. Install the fuel hoses to fuel feed block (1).
  5. Install the generator. Refer to Generator Replacement in Engine Electrical.

    6. Object Number: 791983 Size: SH
  6. Install the fuel feed line (1).

    7. Tighten
    Tighten the fuel feed line to 8 N·m (70 lb in).


    Object Number: 660425 Size: SH
  7. Install the heater pipe assembly.

    8. Tighten
    Tighten the heater pipe bolt to 20 N·m (14 lb ft).


    Object Number: 664853 Size: SH
  8. Install the engine wiring harness assembly. Refer to Engine Wiring Harness Assembly Replacement .
  9. Install the left turbo charged air outlet hose.

    10. Object Number: 664851 Size: SH
  10. Install the right turbo charged air outlet hose.
  11. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  12. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.