GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2001 🢒 L100/L200/LW200 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Heater Core Replacement

Removal Procedure

    Object Number: 878122 Size: SH

    Important: Do not attempt to open the coolant cap while the cooling system is under pressure.

  1. Disconnect the negative battery cable.
  2. Remove the coolant cap from the coolant surge tank.

    3. Caution: Refer to Vehicle Lifting Caution in the Preface section.


    Object Number: 894225 Size: SH
  3. Raise the vehicle.
  4. Remove the lower cradle splash shield to cradle and wheelhouse fasteners and remove the splash shield.

    5. Important: Failure to use a drain hose will result in uncontrolled coolant flow direction.

  5. Slide a pliable piece of hose with an inside diameter of 3/8 in over the radiator drain tube.

    6. Object Number: 894529 Size: SH

    Important: A 7.6 L (8 qt) coolant container will be needed.

  6. Route the hose rearward and down to an approved coolant container.

    7. Important: Only open the drain valve 1-2 turns.

  7. Use a flat-blade screwdriver or pliers to open the radiator drain valve and drain the coolant.

    8. Approximately 3.5  L (4 qt) of coolant can be drained from the radiator. Additional coolant will remain in some cooling system components. When completely drained, close the coolant drain valve and remove the drain hose.


    Object Number: 894225 Size: SH
  8. Install the lower cradle splash shield by sliding the shield (1) between the wheelhouse linen (2) and the wheelhouse (3). Install the splash shield to wheelhouse and cradle fasteners.

    9. Tighten
    Tighten the splash shield-to-wheelhouse and cradle fasteners to 5 N·m (44 lb in).

  9. Lower the vehicle.

    10. Object Number: 893899 Size: SH
  10. Remove the heater inlet hose:
    11. • From the auxiliary water pump outlet on L81 engines
    • From the thermostat outlet on L61 engines

    Object Number: 893904 Size: SH
  11. Remove the heater return hose:
    12. • From the head bridge on L81 engines
    • From the block inlet on L61 engines
  12. Place the end of heater return hose in a container and apply low pressure 34 kPa (5 psi) shop air to the heater inlet hose to blow the coolant out of the heater core.

    13. Object Number: 894220 Size: SH
  13. Remove the right console extension.

    14. Object Number: 894256 Size: SH

    Caution: Heater core pipes may be hot!

  14. Remove the heater core pipe to heater core clamps. The clamps may need to be rotated to gain access to the clamp retaining tab.
  15. Gently pull the pipes forward to remove the pipes from the heater core end tank.
  16. Place absorbent rags under the heater core pipe joints to catch any residual coolant.

    17. Object Number: 894259 Size: SH
  17. Remove the heater core retaining screw and strap.

    18. Important: Use care not to spill any residual coolant on carpet or seats.

    Important: The center console forward edge may need to be pulled outward to allow for the core to be removed.

  18. Pull the heater core out of the HVAC module and into the passenger foot area.

Installation Procedure

    Object Number: 894259 Size: SH
  1. Slide the heater core into the HVAC module being careful not to damage the foam seals.

    2. Tighten
    Tighten the heater core retaining strap screw to 1.9 N·m (9 lb in).


    Object Number: 894256 Size: SH
  2. Install the bushings and O-rings onto the heater core pipes.
  3. Install the heater pipes into the core and install the plastic clamps. The heater pipe clamps will only go on one way. The lower clamp hinge fits into the tab of the heater core retaining strap.

    4. Object Number: 894220 Size: SH
  4. Install the right console extension.

    5. Object Number: 894383 Size: SH
  5. Install the heater inlet hose to recirculation pump on L81, to thermostat outlet on L61.
  6. Install the clamp at the 12 o'clock position.

    7. Object Number: 894387 Size: SH
  7. Install the heater return hose to the thermostat inlet on L61.
  8. Install the clamp at the 12 o'clock position.
  9. Install the heater return hose to return inlet fitting on L81.
  10. Install the clamp at the 3 o'clock position.
  11. Rinse off any coolant that was spilled in the engine compartment.

    12. Object Number: 878122 Size: SH
  12. Connect the negative battery cable.

    13. Tighten
    Tighten the battery terminal bolts to 17 N·m (13 lb ft).

    Important: The vehicle must be level when filling the cooling system.

  13. Slowly add a mixture of 50/50 DEX-COOL® antifreeze and clean water to the coolant surge tank until the level reaches the cold indicator, surge tank seam.

    14. Capacity

        • Fill the L81 cooling system volumes and heater core to 7.4 L (7.8 qt).
        • Fill the L61 cooling system volumes and heater core to 7.0 L (7.4 qt).
  14. Start the engine and inspect for cooling system leaks.
  15. Run the engine until the thermostat has opened, use Tech 2 to verify the ECT is 87°C (188°F) or greater. Add coolant as necessary to bring the level up to the coolant surge tank cold line.
  16. Install the coolant surge tank coolant cap.