Download Except Air-Conditioned Cars 1967 MODELS 1. Disconnect the negative battery cable and drain the radiator. 2. Remove the heater hoses from the core. The top hose connects to the water pump and the lower hose goes to the thermostat housing or intake manifold. 3. Remove the cables and all electrical connections from the heater and defroster assembly. 4. Remove the nuts from the core case studs located on the firewall. 5. From inside the car, remove the case-to-firewall mounting screws and the heater and defroster assembly. 6. Remove the retaining springs and core. 7. Install the core and retaining springs, making sure the core-to-case sealer is in good condition. 8. Complete the installation by reversing the removal procedure. 1968-77 MODELS 1. Disconnect the negative battery cable. 2. Drain the radiator. 3. Disconnect the heater hoses. Plug the core inlet and outlet. 4. Remove the nuts from the air distributor duct studs on the firewall. 5. On 1970-77 Camaros: remove the glove box and radio, then the defroster duct-to-distributor duct screw. Pull the defroster duct out of the way, then pull the distributor duct from the firewall mounting. Remove the resistor wires. Lay the duct on the floor. 7. Remove the core assembly from the distributor duct. 8. Reverse the procedure to install. Use new sealer on the duct flange, if necessary.