GM Corvette 1984-1996 Repair Guide

Heater Core

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REMOVAL & INSTALLATION




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by 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.

1984-88 Vehicles

See Figure 1

  1. Disconnect the negative battery cable. Drain the cooling system into a suitable container.
  2.  
  3. Remove the instrument cluster bezel including the tilt wheel lever and instrument panel pad.
  4.  
  5. Remove the A/C distributor duct and disconnect the flex hose.
  6.  
  7. Remove the right side hush panel.
  8.  
  9. Remove the side window defroster flex hose.
  10.  
  11. Remove the side window defroster to heater cover screws and disconnect the extension.
  12.  
  13. Remove the temperature control cable and bracket assembly at heater cover including disconnecting heater door control shaft.
  14.  

Make sure the ignition switch is

OFF prior to disconnecting the ECM.

  1. Remove the ECM (Electric Control Module) and disconnect the electrical connectors.
  2.  
  3. Remove the tubular support brace from the door pillar to aluminum, instrument panel reinforcement brace.
  4.  
  5. Remove heater core cover attaching screws.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a typical heater core assembly

  1. Remove heater pipe and heater water control bracket attaching screws.
  2.  
  3. Remove heater hose at heater core pipes.
  4.  
  5. Remove the heater core.
  6.  
  7. Installation is the reverse of the removal procedure. Fill the cooling system with the proper type and amount of coolant.
  8.  

1989-96 Vehicles

See Figure 1

  1. Properly disable the SIR air bag system, then disconnect the negative battery cable.
  2.  
  3. Remove the instrument panel upper trim pad as follows:
    1. Remove the lower right trim panel.
    2.  
    3. Remove the fuse box cover and side trim panel.
    4.  
    5. Remove the glove compartment.
    6.  
    7. Remove the right outer air outlet and center air outlet.
    8.  
    9. Remove the console trim plate and accessory trim plate.
    10.  
    11. Remove the windshield defroster grill.
    12.  
    13. Remove the left outer air outlet.
    14.  
    15. Unfasten the dash pad retaining bolts/screws, then remove the pad by pulling rearward and upward.
    16.  

  4.  
  5. Drain the engine coolant into a suitable container. Disconnect the in-vehicle temperature sensor aspirator hose.
  6.  
  7. Unplug the in-vehicle temperature sensor electrical connector.
  8.  
  9. Remove the floor heat deflector attaching screws, right side knee bolster brace and the floor heat deflector.
  10.  
  11. Disconnect the relays from the multi-use relay bracket.
  12.  
  13. Loosen the nuts attaching the wiring harness retainer to the radio receiver, then slide the wiring harness retainer from the receiver.
  14.  
  15. Remove the harnesses from the wiring harness retainer, then remove the wiring harness retainer.
  16.  
  17. Remove the carrier nuts from the right side pillar, the multi-use relay bracket and the passenger knee bolster brace attachments.
  18.  
  19. Unclip the side window defroster duct clip, then remove the duct hose from the knee bolster brace.
  20.  
  21. Pull the carrier back, then remove the passenger knee bolster brace. Detach the electrical connectors from the radio receiver.
  22.  
  23. Remove the multi-use relay bracket and unplug the cruise control module electrical connector.
  24.  
  25. Remove the screws attaching the side window defroster duct to the rear of the heater case. Remove the fuse block from the carrier.
  26.  
  27. Disconnect the vacuum hose from the actuator, then remove the vacuum line retainer tape from the heater. Remove the harness from the retainer clip, mounted on the bottom of the rear heater case.
  28.  
  29. Disconnect the side window defroster duct (center) extension, in the heater case. Remove the rear heater case attaching screws, then the rear heater case half.
  30.  
  31. Remove the high fill reservoir. Disconnect the heater hoses from the heater core. Remove the heater core from the case.
  32.  

To install:
  1. Install the heater core into the case. Connect the heater hoses to the heater core. Install the high fill reservoir, then the rear heater case.
  2.  
  3. Install the side window defroster duct extension. Install the harnesses to the retainer clip on the bottom rear of the heater case.
  4.  
  5. Install the vacuum line and tape onto the retainer. Connect the vacuum hose to the actuator. Install the fuse block to the carrier.
  6.  
  7. Install the side window defroster duct screws to the rear of the heater case. Attach the radio receiver and cruise control module electrical connectors.
  8.  
  9. Install the multi-use relay bracket, the knee bolster brace and attachments. Install the carrier to pillar attachment, then the wiring harness retainer, harness retainer to the radio receiver and the relays to the multi-use relay bracket.
  10.  
  11. Install the floor heat deflector, the right side knee bolster brace and then the floor heat deflector screws. Attach the in-vehicle temperature sensor electrical connectors and the aspirator hose.
  12.  
  13. Install the upper instrument pad assembly in the reverse order of removal. Connect the negative battery cable and enable the SIR system. Properly fill the engine cooling system and check for leaks.
  14.  

 
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