Jeep CJ/Scrambler 1971-1986 Repair Guide

Heater Core

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11

1971-74
  1. Drain the cooling system.
  2.  



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Fig. Fig. 1: Remove the cable retainer from the blend door arm



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Fig. Fig. 2: Disconnect the blend door cable from the control arm



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Fig. Fig. 3: Remove the cable from its mount near the blower motor



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Fig. Fig. 4: Disconnect the defroster duct hose



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Fig. Fig. 5: Disconnect the hoses from the heater case



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Fig. Fig. 6: Remove the center heater case mounting bolt from the engine compartment side



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Fig. Fig. 7: Remove the left side heater case mounting bolt from the engine compartment side



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Fig. Fig. 8: Remove the right side heater case mounting bolt from the engine compartment side



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Fig. Fig. 9: Lower the heater case onto the floor of the vehicle, then remove it from the vehicle



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Fig. Fig. 10: Remove the heater case back cover retaining screws, then remove the cover



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Fig. Fig. 11: Pull the heater core from the heater case


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Mark the duct halves to be sure they are reassembled properly.
  2.  
  3. Remove the screws that fasten the two halves of the duct together.
  4.  
  5. Remove the screws that secure the heater core to the duct.
  6.  
  7. Remove the heater core from the vehicle.
  8.  
  9. Install in reverse order of the above procedure.
  10.  

1975-76
  1. Drain about two quarts of coolant from the radiator.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the battery cables, remove the battery and battery box.
  2.  
  3. Disconnect the heater hoses.
  4.  
  5. Disconnect the damper door control cables.
  6.  
  7. Disconnect the blower motor wiring harness at the switch and ground wire at the instrument panel.
  8.  
  9. Remove the glove box.
  10.  
  11. Disconnect the water drain hose and defroster hose.
  12.  
  13. Disconnect the heater-to-air deflector duct at the heater housing.
  14.  
  15. Remove the nuts from the heater housing studs in the engine compartment and remove the heater housing assembly.
  16.  
  17. Remove the heater core from the heater housing.
  18.  
  19. Install the heater core in the reverse order of removal, refill the radiator, run the engine and check for leaks.
  20.  

1978-86

The heater housing assembly has to be removed to get out the heater core.

  1. Drain about two quarts of coolant.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the heater hoses at the engine side of the firewall.
  2.  
  3. Detach the heater control cables.
  4.  
  5. Disconnect the motor wiring.
  6.  
  7. Detach the water drain hose and the defroster hose.
  8.  
  9. Remove the nuts from the studs in the engine compartment.
  10.  
  11. Tilt the heater housing assembly down and pull it back toward the inside of the vehicle.
  12.  
  13. Lay the assembly on a flat surface and remove the screws that retain the back cover of the housing.
  14.  
  15. Remove the back cover from the housing and pull the heater core out of the housing.
  16.  
  17. When installing the heater core be sure to seal the core tubes where they stick through the case.
  18.  
  19. Install the back cover retaining screws and install the heater case into the vehicle.
  20.  
  21. Reconnect all of the cables and hoses then refill the cooling system. Check the operation of the heater.
  22.  

 
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