1974-1983 Pontiac Mid-size Heater Core Repair Guide

REMOVAL & INSTALLATION Exploded view of the heater assembly components-1980-81 LeMans shown Heater cable routing-Phoenix and Ventura Heater control cable and panel mounting-LeMans and Grand Prix To remove the heater core, unfasten the lower windshield trim panel screws ... ... then remove the lower windshield trim panel Remove the rubber seal from around the cowl screen If necessary, disconnect the windshield washer hose Unfasten the windshield cowl screen retainers ... ... then remove the cowl screen Unfasten the heater case cover retaining bolts ... ... then remove the heater case cover assembly Unscrew the heater hose clamps ... then disconnect the heater hoses from the core Remove the heater core bracket retaining bolt ... ... then remove the heater core from the case.
1974-77 GTO, LeMans and Grand Am WITHOUT AIR CONDITIONING
1. Drain the radiator.
2. Disconnect the heater hoses at the air inlet assembly.
3. Remove nuts from core studs on firewall (under hood). Remove the glove box.
On 1977 LeMans, remove glove box and door, then remove heater outlet from case. Remove defroster duct screw on all models.
4. From inside the car, pull the heater assembly from the firewall.
5. Disconnect control cables and wires, then remove heater assembly.
6. To remove core, unhook retaining springs or strips.
7. To install, reverse removal procedure, making sure core is properly sealed during installation.

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