Thanks. I will try using one of the IR thermometers if I can get my hands on one (would this be at a hardware store or an auto store?).

Also will report back if the temperature happens to drop to correct level as air leaves the system.

I may try the thermostat test, but the chances of two different thermostats both being equally bad is almost nil.

As far as the radiator, yes, I know it didn't go bad in such a short time, but it can't hurt to put in a new one because my old one does drain some particulate matter each time I drain/flush the system, so I'd like to do it preventatively before it gets plugged up or plugs up the block.