How to Replace the Heater Core in a Subaru Outbackby Contributor
The difficulty of replacing an Outback's heater core depends mainly on the vehicle's age. Newer models should require the complex removal of the entire instrument panel. On older vehicles, you should only have to remove the steering support beam.
Unplug the Outback's negative battery cable. Discharge or drain the air conditioning system and cooling systems.
Disconnect the expansion valve and pipe in the engine compartment by removing the bolts that secure them. Remove the heater hoses by releasing the clamps.
Remove the instrument panel, support beam and blower motor assembly. Unplug the actuator connector.
Loosen the heater unit's nuts and bolts to remove the unit. Separate the unit case to remove the heater core.
Install the new core into the heater unit. Connect everything in reverse order.
Refill the cooling and air conditioning systems to the correct levels. Properly charge the air conditioning system.
Shut off the Outback's power by disconnecting the negative battery cable. Drain the engine cooling system.
Remove the air intake system, heater hoses and air conditioning unit. Remove the airbag control unit (you'll need a Torx wrench) and disconnect its main wiring harness connector near the steering support beam.
Loosen the support beam's bolts and nuts and remove the beam, then disconnect the servo connector to reach the heater. Remove the heater unit and separate its case to remove the heater core.
Replace the new core in the heater unit and reconnect it. Connect the servo connector support beam, engage the airbag system and connect the AC unit, heater hoses and air intake system.
Fill the cooling system to the correct level. You may use the same coolant if you drained it into a clean container.