GM Firebird 1967-1981 Repair Guide

Heater Core

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REMOVAL & INSTALLATION



Models Without Air Conditioning
1967 VEHICLES

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

  1. Disconnect the negative battery cable and drain the radiator.
  2.  
  3. Remove the heater hoses from the core. The top hose connects to the water pump and the lower hose goes to the thermostat housing.
  4.  
  5. Remove the cables and all electrical connections from the heater and defroster assembly.
  6.  
  7. Remove the nuts from the core case studs located on the firewall.
  8.  
  9. From inside the car, remove the case-to-firewall mounting screws and also the heater and defroster assembly.
  10.  
  11. Remove the retaining springs and core.
  12.  
  13. Install the core and retaining springs, making sure the core-to-case sealer is in good shape.
  14.  
  15. Complete the installation by reversing the removal procedure.
  16.  

1968-77 VEHICLES

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

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the radiator.
  4.  
  5. Disconnect the heater hoses. Plug the core inlet and outlet.
  6.  
  7. Remove the nuts from the air distributor duct studs on the firewall.
  8.  
  9. From beneath the dash, drill out the lower, right-hand distributor duct stud with a 1 / 4 in. drill.
  10.  
  11. On 1970 and later models remove the glove box and radio, then the defroster duct-to-distributor duct screw.
  12.  
  13. Pull the distributor duct from the firewall mounting. Remove the resistor wires. Lay the duct on the floor.
  14.  
  15. Remove the core assembly from the distributor duct.
  16.  
  17. Reverse the procedure to install.
  18.  

1978-81 VEHICLES

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

  1. Disconnect the negative battery cable. Drain the radiator. Disconnect heater hoses.
  2.  
  3. Remove the nuts that attach the heater case to the firewall from the firewall side. Then, remove the screws from inside the car.
  4.  
  5. Remove the glovebox and door. Remove the screws attaching the heater outlet duct to the heater case, and remove the duct.
  6.  
  7. Remove the defroster screw. Pull the heater case out. The core may now be pulled out of the case.
  8.  
  9. Reverse the removal procedure to install. Use new seals between the heater case and the firewall.
  10.  

Models With Air Conditioning


CAUTION
Please refer to Repair Guide 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.

Removal of the heater core from air conditioned cars requires the opening (evacuation) of the refrigerant lines. These lines contain pressurized Freon gas, capable of inflicting serious injury upon contact. Do not, under any circumstance, disconnect or loosen any refrigerant hose. This should be attempted only by a qualified refrigeration repairman. To avoid the possibility of accidents, heater core removal on air conditioned cars, and all other air conditioning service procedures have been deleted from the guide.

 
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