GM Service Manual Online
For 1990-2009 cars only

The expansion (orifice) tube is located at the condenser to evaporator tube connection in the condenser tube.

Important: When you replace an expansion (orifice) tube, compare the design of the orifice tube to the design of the replacement part for the correct selection. The different styles of orifice tubes are not interchangeable.

Removal Procedure


    Object Number: 599787  Size: SH
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Remove the upper filler panel. Refer to Hood Close Out Filler Replacement in Body Front End.
  3. Remove the bolt holding the evaporator hose assembly to the condenser.
  4. Remove the evaporator tube block fitting nut.
  5. Remove the evaporator tube from the condenser.
  6. Important: Cap or tape the open end of the evaporator tube immediately to prevent contamination.

  7. Remove and discard the O-ring seal.
  8. Using needle nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube without touching the filter screen and pull to remove the tube; cap or tape the evaporator tube to prevent contamination.
  9. Use the following procedure in order to remove a restricted or plugged expansion (orifice) tube:
  10. 8.1. Remove as much as possible of the impacted residue.
    8.2. Use a heat gun in order to apply heat to the expansion (orifice) tube. Apply the heat approximately 7 mm (1/4 in) from the dimples on the inlet pipe.
    8.3. While applying heat, use needle-nosed pliers in order to grip the orifice tube. Use a turning motion along with a push-pull motion.

    This will loosen the impacted orifice tube and remove the tube.

    8.4. Swab the inside of the evaporator inlet line to clean any contamination from the line.

    Object Number: 296238  Size: SH
  11. Inspect the expansion (orifice) tube for the following conditions and clean or replace with a new tube as indicated:
  12. • Broken plastic frame; replace tube
    • Filter screen (1,2) torn, damaged or plugged with fine gritty material; replace tube
    • Brass orifice tube (3) damaged or plugged; replace tube
    • Filter screen (1) coated with metal chips, flakes, or slivers; coating may be removed with low pressure shop air and reused if cleaned satisfactorily
    • If reusing the tube, install a new O-ring (4)

Installation Procedure


    Object Number: 296238  Size: SH
  1. Lightly coat the new orifice tube O-ring seal (4) with mineral base 525 viscosity refrigerant oil.
  2. Using needle-nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube (short filter screen (2) inlet side of tube) without touching the filter screen and insert the tube (long filter screen (1) outlet side first) fully into the evaporator line.
  3. Remove the cap or tape from the evaporator tube.
  4. Using a lint-free clean, dry cloth, carefully clean the sealing surfaces of the tube fittings.

  5. Object Number: 599787  Size: SH
  6. Install a NEW O-ring seal on the condenser tube.
  7. Coat the O-ring seal with 525 viscosity refrigerant oil.

    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.

  8. Install the evaporator tube and the block fitting nut to the condenser.
  9. Tighten
    Tighten the block fitting nut to 16 N·m (12 lb ft).

  10. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  11. Inspect the system operation.
  12. Perform the leak test. Refer to Leak Testing .
  13. Install the upper filler panel. Refer to Hood Close Out Filler Replacement in Body Front End.