I just replaced the radiator in my 81 spider. I removed the air filter box as suggested here and the coolant "T". I think the added working room with them removed is worth the time. I also used new coolant as the existing was over 5 years old. I have the plastic "T" in the heater line but filled the system per the instruction sheet you have. After the car cooled down I topped off from the "T" in the heater line. All seems good.
I'm gonna remove existing radiator (damaged lower tank) and replace with another similar radiator. Any tips or tricks to this job? I am a 77 yr old fart with a few hand tools.and a 1982 fiat spider that I dearly love! Does elec fan come out with radiator, or have to remove fan first? Any help will be appreciated.