GM Service Manual Online
For 1990-2009 cars only

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

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: 588303  Size: SH
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Remove the bolt holding the evaporator hose assembly to the condenser.
  4. Remove the evaporator hose assembly from the condenser.
  5. Important: Cap or tape the open end of the condenser line immediately to prevent contamination.

  6. Remove and discard the O-ring seal.
  7. 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.
  8. Use the following procedure in order to remove a restricted or plugged expansion (orifice) tube:
  9. 7.1. Remove as much as possible of the impacted residue.
    7.2. 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.
    7.3. 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.

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

    Object Number: 296238  Size: SH
  10. Inspect the expansion (orifice) tube for the following conditions and clean or replace with a new tube as indicated:
  11. • 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. Remove the cap or tape from the evaporator line.
  3. Using needle-nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube (long filter screen (1) inlet side of tube) without touching the filter screen and insert the tube (short filter screen (2) outlet side first) fully into the evaporator line.
  4. Remove the cap or tape from the condenser line.
  5. Using a lint-free clean, dry cloth, carefully clean the sealing surfaces of the line fittings.

  6. Object Number: 588303  Size: SH
  7. Install a NEW O-ring seal on the condenser tube.
  8. 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.

  9. Install the evaporator hose assembly and the bolt to the condenser.
  10. Tighten
    Tighten the bolt to 25 N·m (18 lb ft).

  11. Lower the vehicle.
  12. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  13. Inspect the system operation.
  14. Perform the leak test. Refer to Leak Testing .