GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1998 🢒 Silhouette Ext. 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Auxiliary Air Conditioning Evaporator Replacement

Removal Procedure
  1. Remove the rear heater A/C module. Refer to Auxiliary HVAC Module Replacement .
  2. Remove the thermal expansion valve. Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  3. Remove the air distribution valve vacuum actuator. Refer to Auxiliary Mode Valve Actuator Replacement .

    4. Object Number: 400630 Size: SH
  4. Remove the screws from the HVAC module base cover.
  5. Remove the HVAC base cover.
  6. Remove the screws from the HVAC module

    7. Important: Be careful when separating the HVAC case halves not to damage the heater core cooling fins.


    Object Number: 400631 Size: SH
  7. Separate the HVAC module case halves.

    8. Object Number: 400633 Size: SH
  8. Lift the evaporator core from the module half.
  9. Remove the insulator seal from the evaporator core.

Installation Procedure
  1. Install a new insulator/seal on evaporator core.

    2. Object Number: 400633 Size: SH
  2. Install the evaporator core into the HVAC module case.

    3. Important: Make certain the seal on the evaporator core pipes lines up with the seal grooves in the HVAC case halves.


    Object Number: 400631 Size: SH
  3. Assemble the halves of the HVAC module case.

    4. 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.

  4. Install the screws into the HVAC module case.

    5. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).


    Object Number: 400630 Size: SH
  5. Install the HVAC base cover.
  6. Install the retaining screws to the HVAC base cover.

    7. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  7. Install the vacuum actuator. Refer to Auxiliary Mode Valve Actuator Replacement .
  8. Install the thermal expansion valve. Refer to Auxiliary Air Conditioning Evaporator Thermal Expansion Valve Replacement .
  9. Install the rear heater A/C module. Refer to Auxiliary HVAC Module Replacement .