The heater core is the most important part of the Dodge Durango's heating system, as it acts like a miniature radiator for the engine coolant/antifreeze. If you need to remove the heater core for replacement or inspection, you will need to remove the instrument panel from the truck. This exact process can vary, depending on the year of the Durango.
The air-conditioning system needs to be discharged first, and this should only be done by a licensed technician. Once the system is discharged, disconnect the negative battery cable. Drain the engine coolant into a large container by removing the drain plug at the radiator and then the engine block; this may require a wrench or pliers.
To disconnect the heater hoses at the core, slide away the clamps from their connections at the firewall and detach the hoses from the wall. Plug the openings with rubber or tape them up to prevent contaminants from entering the system.
Before removing the instrument panel, make sure the front wheels are facing straight ahead, then lock the steering column. Make sure the battery cable has been disconnected for at least two minutes so the air bags are disabled.
Remove all the dashboard trim panels; this can include the kick panels, the panel's top cover, the bezels covering the instrument cluster and stereo, glove box and steering column covers. Most of these will require a screwdriver, wrench and/or trim stick to detach the fasteners.
Lower the steering column once you've removed its covers, then disconnect all the electrical connectors on the driver's side of the panel. You may also need to disconnect parts like the parking brake rod, the brake light switch, center console, wire harnesses to the occupant restraint and floor pan (peel back the carpeting to find the latter) and the stereo amplifier.
Once all connectors are disconnected, remove the instrument panel's retaining fasteners with a wrench or screwdriver. Lift the panel out and away from the firewall and then out of the truck; you may need two people to do this.
Each component of the heater/AC system has its own retaining bracket. Once the instrument panel is out, remove the housing bracket for the heater/air-conditioner by unscrewing its fastener with a wrench, then disconnect the retaining bracket for the heater core tube at the firewall. To detach the heater core tubes from the core, release their retaining clips. Disconnect the retaining bracket for the heater core itself, then lift the heater core out of its housing.
