GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 43181 Heater Line Quick Connect Release Tool
    • J 38185 Hose Clamp Pliers

Removal Procedure

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  2. Remove the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement in Engine Cooling.
  3. Using the J 43181 , disconnect the inlet heater hose from the heater core.
  4. 3.1. Install the J 43181 to the quick connect on the outlet heater core hose (2).
    3.2. Close the tool around the inlet heater core hose.
    3.3. Firmly pull the tool into the quick connect end of the heater hose.
    3.4. Firmly grasp the heater hose. Pull the heater hose forward in order to disengage the hose from the heater core.

    Object Number: 735781  Size: SH
  5. Position the hose clamp at the engine outlet using J 38185 .
  6. Remove the heater inlet hose (4) from the engine block.
  7. Remove the nut retaining the coolant bypass valve to the cowl.
  8. Remove the vacuum hose from the coolant bypass valve.
  9. Remove the coolant bypass valve.
  10. Position the clamps at the coolant bypass valve.
  11. Remove the heater inlet hoses form the coolant bypass valve.

Installation Procedure


    Object Number: 735781  Size: SH
  1. Apply coolant to the end of the heater inlet hoses.
  2. Important: When installing a new heater inlet hose, place the clamps on the hose before installing the hose to the inlet hose fitting at the engine block.

  3. Install the heater inlet hose to the inlet hose fitting at the engine block.
  4. Install the coolant bypass valve (6).
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the nut retaining the coolant bypass valve to the cowl.
  7. Tighten
    Tighten the nut to 10 N·m (89 lb in).

  8. Install the vacuum hose to the coolant bypass valve.
  9. Install the inlet heater hose to the engine block.
  10. Position the inlet heater hose clamp at the engine block using J 38185 .
  11. Connect the heater inlet hose to the heater core.
  12. Important: Firmly push the quick connect onto the heater core pipe until you hear an audible click.

  13. Install the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement in Engine Cooling.
  14. Fill the engine cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.