GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Pickup - 4WD (CNG) 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 CNG Fuel Tank Cover Replacement

Removal Procedure

    Caution: Natural gas is highly flammable. In order to reduce the risk of fire and personal injury, keep sparks, flames, and smoking materials away from the vehicle while you perform the Compressed Natural Gas (CNG) fuel system service.

    Caution: The Compressed Natural Gas (CNG) system operates at pressures up to 24820 kpa (3600 psi). Relieve the CNG fuel system pressure before servicing CNG fuel system components in order to reduce the risk of fire and personal injury.

  1. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief in the Engine Controls section (supplement).

    2. Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  2. Disconnect the negative battery cable.

    3. Object Number: 296365 Size: SH
  3. Remove the fill door bolts.
  4. Remove the fill door.
  5. Remove the fill plate bolts.
  6. Remove the fill plate from the cover.

    7. Object Number: 296506 Size: SH
  7. Remove the fill valve nut (1).
  8. Remove the fill plate (2).

    9. Object Number: 296368 Size: SH
  9. Remove the bolt covers.
  10. Remove the tank cover bolts.
  11. Remove the tank cover.

Installation Procedure

    Object Number: 296368 Size: SH
  1. Install the tank cover.

    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 tank cover bolts.

    3. Tighten
    Tighten the bolts to 27 N·m (20 lb ft).

  3. Install the bolt covers.

    4. Object Number: 296506 Size: SH
  4. Install the fill plate (2).
  5. Install the fill valve to plate mounting nut (1).

    6. Tighten
    Tighten the nut to 41 N·m (30 lb ft).

  6. Install the fill plate in the cover.
  7. Install the fill plate bolts.

    8. Tighten
    Tighten the bolts to 12 N·m (108 lb in).


    Object Number: 296365 Size: SH
  8. Install the fill door with the fill door bolts.

    9. Tighten
    Tighten the bolts to 12 N·m (108 lb in).

  9. Connect the negative battery cable.

    10. Tighten
    Tighten the bolt to 15 N·m (11 lb ft).