If you are mechanically inclined, it will take 3.5-4.0 hours. The hardest part is getting to nuts that are in the firewall area down low. You either drill a hole in the wheel well or take the wheel well out complete. There are 3 nuts in the firewall and one bolt in the pass.. compartment.
I jus did mine less than 3 weeks ago. Make sure ya dont run the heater or anything prior to changing it.
When you take the heater hoses off, stuff something in the heater core outlets to keep from making a mess. I lost about 1/4 cup of fluid when I did this. And tie the heater hoses up high outa the way so they dont leak out. Its not necessary to drain any fluid from rad.
I have working A/C and I did not have to mess with this or remove any part of this.
When removing the heat exchanger and assembly from under the dash, jus take your time. Dont jus start ripping it out.
You will have to COMPLETELY dissassemble the assembly that holds the heater core, Im talking every single screw and nut. You will have to move the pivot rods that move the vent and heater doors. Also all the hardware on the top of the box. Jus pay very close attention to where everything goes. It can be pretty tricky.
I removed the pass. seat and pulled carpet back incase I made a mess, which I didnt. But the seat being removed really made it easy to work on the box.
Jus take your time and look to see how things go and bolt up. Its actually pretty easy, jus takes time.