
So step one I go online to see if the local parts store has a heater core in stock. They did. $60. OK, so I then go to there online repair database to see what I am in for.
I look up "heater core" 1991-1999 Ranger. I read the first 2-1/2 pages and it seems easy enough. I print the 5 page hard copy. I go out and drain off some coolant and prepare for the task at hand. I look under the dash and say wait a minute, my airbox doesn't look like the photo on the paper. Then to my surprise, on the top off page three is a little side note: "NOTE: It is necessary to remove dashboard on 1994-1999 models, refer to factory manual". Oh joy.

It took me about an hour to locate the hidden fasteners I needed to remove for the dash. The dash came off easier than I expected with a vent trim piece the only casualty from aggrevation.
I had to pull the blower motor off the engine fire wall to access the air box or "plenum" fasteners as they called it in the instructions. After wrestilng the dash out of place I tried to pull the heater unit away from the firewall. No good. I looked for the hangup and I had missed a 8MM nut located behind the engine block on the firewall. The kind that gives you only 1.500" to get at. After dropping my 1/4" ratchet twice and having to fish it off the bellhousing, I finished slowly with a boxwrench.
That loosend the heater box but I could not get it pulled away far enough to get the heater core pipes through the firewall. The dash was about 14" from the firewall and it was not enough room! So next I figured I would have to disconnect the steering wheel. Looking underneath I found a support bracket and disconnected that. It gave me enough space to slide the pipes through the firewall. The only smart thing Ford did was put a access cover on top the heater box so you could slide the heater core out.
I jump in the wifes car to go buy the new core and the kid at the parts store says "that comes with a lifetime warranty". Now my Ranger has 250K on it and I tell the kid "like yea, I want to do this again in my lifetime"

All in all it went back together easier than it came apart. Total was about 6 hours labor. Now however my radio has no sound. I probably pulled some pigtail loose along the way. I'll wait until Spring to look into that. I am still not warmed up
