How to Replace the Heater Core in a Toyota Corolla
Replacing your Toyota Corolla's heater core is best left for an expert if at all possible. Changing the core itself isn't hard, but getting to it is. You must remove the air bags, steering column, dashboard and evaporator in order to reach the heater.
- Replacement heater core
- Torx socket wrench
- Steering wheel puller
- Liquid line tool
- Engine coolant
Remove the Old Core
Unplug the Corolla's the negative battery cable and wait 90 seconds for the air bags to lose energy. Drain the coolant from the cooling system, disconnect the heater hoses and discharge the air conditioner refrigerant.
Take out the driver air bag by loosening the screw covers on the steering wheel and the module-to-wheel Torx screws. Remove the steering wheel nut and press the wheel from the steering column. Remove the glove box and passenger air bag.
Detach the steering column. Remove the front door scuff plates, cowl side trims, front pillar garnishes, lower finish panel, hood lock control cable, lower insert, cluster finish panel, steering column cover and combination switch, heater-to-register duct, combination meter, column-to-dashboard fasteners, and steering column shaft pinch bolt.
Disassemble and remove the dashboard. The lower left and right side panels, shifting hole knob or bezel rear console box, center lower cluster finish panel, stereo opening cover, lower center finish panel, air conditioning panel, center cluster finish panel, radio, and electrical connectors.
Disconnect the evaporator housing. Remove the heater-to-register duct, lower defroster nozzle, braces, reinforcement. Disconnect the cruise control actuator connector and set bolts and the refrigerant line clamps. Remove the tube and drain hose grommets, air conditioning amplifier and the evaporator housing.
Remove the rear heater ducts by pulling back the carpet. Remove the heater housing by disconnecting the wiring harness, housing-to-chassis nuts and the heater housing. Remove the air duct from the housing, then the heater core from the housing.
Install the New Core
Install the new heater core, attach the air duct and connect the housing back to the chassis. Install the heater ducts and replace the carpet.
Reinstall the evaporator housing, dashboard, steering column and air bags into the Corolla. Perform everything from Section 1 in reverse order.
Connect the heater hoses back to the core. Fill the cooling system, reconnect the battery cable, then evacuate, charge and leak test the air conditioner refrigerant.