It took a couple hours for me. I spent an hour trying to persuade the plastic screws off of the lower dash kick panel cloth. Only 2 of the 5 backed off; so I gave up and cut them off. Got the heater core out and replaced in 15 minutes; fire up the truck and coolant is pouring out from the top hose at the water pump. Tightened the crap outta the stainless hose (leftover from another heater core project) and waited for the truck to cool down so I could pop the radiator cap and try again. Been running good since. The old core looked good, but I think it's clogged. My temp gauge would spike and drop to "N" in normal and back again when driving. Now it doesn't do that. I will see if I can clean and flush the old core and see if I can reuse it.
I feared that this heater core would be like my Crown Vic as that involved dropping the steering column, pulling the entire dash, and finding all of the screws and nuts that hold the heater core box to the firewall. The manual said 5 nuts hold the box in, but they must have missed one or two as that sucker was still stuck to the firewall. After a day of that crap, I sent it to the mechanic, who couldn't figure it out either. So he cut a hole in the firewall and extracted it from there. Very annoying!!! And yeah, in the process, I must have severed a major vacuum line when pulling the dash as it hesitates and stumbles at lower rpms. When I pull the engine from that car, I will replace the line that I know I severed. I was saddened to read that the newer Rangers went back to that system of changing heater cores
XLTbeater