GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Evaporator Core

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REMOVAL & INSTALLATION




CAUTION
Please refer to Routine Maintenance before discharging the compressor or disconnecting air conditioning lines. Damage to the air conditioning system or personal injury could result. Consult your local laws concerning refrigerant discharge and recycling. In many areas it may be illegal for anyone but a certified technician to service the A/C system. Always use an approved recovery station when discharging the air conditioning.

1964-70
  1. Properly discharge and recover the refrigerant in the A/C system using a suitable recovery station.
  2.  
  3. Remove the right fender skirt and hood hinge.
  4.  
  5. Disconnect the high pressure line at the condenser and the suction throttling valve to the compressor line at the suction throttling valve. Cover all lines immediately to prevent system contamination and subsequent damage.
  6.  
  7. Take out the three screws attaching the duct assembly to the evaporator housing and the blower assembly.
  8.  
  9. Take out the nine bolts holding the evaporator assembly to the cowl and lift out the assembly.
  10.  
  11. The core can be removed by removing the screws attaching the core to the case and lifting the core from the case.
  12.  
  13. After installing the evaporator core and tightening the refrigerant lines, evacuate, leak test and charge the system.
  14.  

1971-73

Core removal and installation may be made without removing the entire evaporator assembly.

  1. Properly discharge and recover the refrigerant in the A/C system using a suitable recovery station.
  2.  
  3. Disconnect the negative battery cable, then remove the carburetor air cleaner assembly.
  4.  
  5. Remove the expansion valve bulb from the core outlet line and the core outlet line at the POA valve. Disconnect the core outlet line at the expansion valve.
  6.  
  7. Remove the clamp screw and move the expansion valve and line out of the way.
  8.  
  9. Disconnect all wires and hoses attached the the evaporator assembly.
  10.  
  11. Remove the nuts and screws from the evaporator cover, and carefully pull the cover upward and outward.
  12.  
  13. Remove the core retaining screws and remove the core.
  14.  

To install:
  1. Install the core and tighten the retaining screws.
  2.  
  3. Install the cover, then secure using the nuts and screws.
  4.  
  5. Connect all wires and hoses to the evaporator assembly.
  6.  
  7. Reposition the expansion valve and line, then tighten the clamp screw.
  8.  
  9. Connect the core outlet line to the expansion valve, then install the expansion valve bulb to the core outlet line and the the core outlet line to the POA valve.
  10.  
  11. Install the carburetor air cleaner assembly, then connect the negative battery cable.
  12.  
  13. After checking that all the refrigerant lines are properly tightened, evacuate, leak test and charge the system.
  14.  

1974-77

Core removal and installation may be made without removing the entire evaporator assembly.

  1. Properly discharge and recover the refrigerant in the A/C system using a suitable recovery station.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the carburetor air cleaner assembly, AIR pipe at the manifold, PCV, carburetor heat stove and engine thermal switch, where necessary.
  6.  
  7. Disconnect the oil bleed and the core inlet and outlet lines at the VIR or accumulator assembly.
  8.  
  9. Remove the bracket screw and move the VIR or accumulator assembly out of the way.
  10.  
  11. Disconnect the vacuum lines and remove the vacuum tank and bracket.
  12.  
  13. Disconnect all wires and hoses attached to the evaporator case.
  14.  
  15. Remove the nuts securing the evaporator cover to the dash panel and the screws attaching the cover to the evaporator.
  16.  
  17. Remove the cover upward and outward.
  18.  
  19. Remove the core.
  20.  

To install:
  1. Install the core, then install the core cover and secure using the retaining nuts.
  2.  
  3. Connect the wires and hoses to the evaporator case, then install the vacuum tank and bracket. Connect the vacuum lines.
  4.  
  5. Reposition the VIR or accumulator assembly and install the bracket screw.
  6.  
  7. Connect the oil bleed and the core inlet/outlet lines at the VIR or accumulator assembly.
  8.  
  9. Where removed, install the carburetor heat stove, PCV, AIR pipe to the manifold and the air cleaner assembly.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. After checking that all the refrigerant lines are properly tightened, evacuate, leak test and charge the system.
  14.  

1978-88
  1. Properly discharge and recover the refrigerant in the A/C system using a suitable recovery station.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the module's rubber seal and screen. If necessary, disconnect the washer nozzle from the cowl.
  6.  
  7. If necessary, remove the right windshield wiper arm.
  8.  
  9. As applicable, remove or disengage, the diagonstic connector, high blower relay, thermostatic switch, ground strap and/or electrical connectors from the heater core module cover.
  10.  
  11. Loosen the retainers and remove the module's top cover. The cover is sealed to the module and this seal must be broken before the cover can be removed. Be absolutely sure that all cover fasteners are removed before attempting to break the seal or cover damage will result. Take your time and be careful not to force and crack or otherwise damage the cover.
  12.  

On many late model vehicles, cover interference with the vehicle's bulkhead will may removal difficult. On these vehicles it will be necessary to loosen the windshield's chromed lower trim plate for the necessary clearance.

  1. Remove the accumulator bracket screws.
  2.  
  3. Disconnect and tape the refrigerant lines at the accumulator and liquid line.
  4.  
  5. Remove the evaporator core.
  6.  

To install:
  1. Thoroughly clean the mating surfaces of the cover and the module of all old sealer.
  2.  
  3. Install the evaporator core, then remove the tap and connect the refrigerant lines at the accumulator and liquid line.
  4.  

When connecting the refrigerant lines, use new O-rings dipped in clean refrigerant oil.

  1. Install the accumulator bracket screws.
  2.  
  3. Apply a coating of sealant to the cover, then install the cover and tighten the fasteners. If the windshield trim plate was loosened for clearance, reposition and secure it.
  4.  
  5. Engage the electrical connectors and components to the module cover, as applicable.
  6.  
  7. If removed, install the right wiper arm.
  8.  
  9. Install the module screen and rubber seal. If removed, install the washer nozzle to the cowl.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. After checking that all the refrigerant lines are properly tightened, evacuate, leak test and charge the system.
  14.  

 
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