Heater core replacement?

If it was leaking coolant that bad then I wouldn't be surprised at all if everything in that dash is soaked with it. Will take some time for that to evaporate and dry up completely. It can definitely be blown out of the vents as well.

Remove the HVAC module assembly
Remove the heater core case cover
Remove the heater core bracket and screw
Remove the heater core

1. Disable the air bag by performing the following procedure:
A. Place the front wheel in the straight-ahead position.
B. Turn the ignition switch to the LOCK position.
C. Remove the air bag fuse from the fuse block.
D. At the left side, remove the sound insulator.
E. At the driver-s side, disconnect the Connector Position Assurance (CPA) and the yellow 2-way electrical connectors and the lead to the passenger-s side SIR module.

2. Disconnect the negative battery cable.
3. Drain the cooling system into a clean container for reuse.
4. Disconnect the heater hoses from the heater core and remove the drain tube from the heater/air conditioning housing.
5. Remove the steering wheel by removing or disconnecting the following:

CAUTION
Place the SIR module in a safe place with the front facing upward.

2 SIR module-to-steering wheel screws (located at the rear of the steering wheel), and the module
SIR module and disconnect the electrical connector and remove the SIR module

Horn and cruise control electrical connectors
Steering wheel-to-steering column nut
Steering wheel from the steering column

6. Remove the console by removing or disconnecting the following:

Front seats
Fold the console compartment upward
Console trim plate
Rear cup holder
Console-to-chassis screws and the console

7. Remove the instrument panel by removing or disconnecting the following:

NOTE
There is a screw located in the recess in the center of the cover.

Defroster grille
Instrument panel valance screws and the valance
Instrument panel end caps from both sides
Screws located under the instrument panel end caps
Instrument panel compartment
Steering column covers
Steering column stalks
Instrument cluster and accessory trim plates
Instrument cluster fasteners, disconnect the electrical connectors and remove the cluster
Heater/air conditioning control assembly
Stereo/tape deck assembly
Ignition switch
Upper windshield side garnish molding
Loosen the center console, pull it rearward to disengage it from the instrument panel
Instrument panel-to-tie bar screws
Instrument panel
Outlet from the heater/air conditioning housing
Heater core cover-to-heater/air conditioning housing

Heater core-to-heater/air conditioning housing clamps
Heater core

To install:

1. Install or connect the following:

NOTE
There is a screw located in the recess in the center of the cover.

Heater core
Heater core-to-heater/air conditioning housing clamps
Heater core cover-to-heater/air conditioning housing

Outlet to the heater/air conditioning housing

2. Install the instrument panel by installing or connecting the following:

Instrument panel
Instrument panel-to-tie bar screws
Move the center console forward and engage it to the instrument panel
Upper windshield side garnish molding
Ignition switch
Stereo/tape deck assembly
Heater/air conditioning control assembly
Instrument cluster, connect the electrical connectors and install the cluster fasteners
Instrument cluster accessory trim plates
Steering column stalks
Steering column covers
Instrument panel compartment
Instrument panel end caps, install the screws
Instrument panel end caps on both sides
Instrument panel valance and the valance screws
Defroster grille

3. Install the console by installing or connecting the following:

Console and the console-to-chassis screws
Rear cup holder
Console trim plate
Front seats

4. Install the steering wheel by installing or connecting the following:

Steering wheel to the steering column
Steering wheel-to-steering column nut and torque to 30 ft. Lbs. (41 Nm)
Horn and cruise control electrical connectors
SIR module and connect the electrical connector
SIR module and torque the 2 module-to-steering wheel screws to 89 inch lbs. (10 Nm)
Heater hoses to the heater core and install the drain tube to the heater/air conditioning housing

5. Refill the cooling system.
6. Connect the negative battery cable.
7. Enable the SIR or air bag by installing or connecting the following:

Connector Position Assurance (CPA), the yellow 2-way electrical connectors and the lead to the passenger-s side SIR module (located on the drivers- side)
Sound insulator, located on the left side
Air bag fuse to the fuse block

A. Turn the ignition switch to RUN and verify that the Air Bag Warning light flashes 7-9 times and turns OFF.

NOTE
If the SIR system does not operate as described, perform the SIR diagnostic system check.

8. Operate the engine to normal operating temperatures; then, check the climate control operation and check for leaks.

Yes, disconnect the battery and allow the vehicle to sit for at least 20 minutes before you start working on it.