Re: 93 probe GT over heating
I'm by far no expert, but I think you need to add coolant to the radiator 'till it's full (you can see it in the filler neck), then add a little to the reservoir, at least that's how I do it on my '94 Probe and other vehicles I own.
When does it overheat, and how badly? Is the water pump making noise? It's on the fan belt side of the engine, and will usually make a howling/whining or grating noise early on, and progress to grinding. Mine was recently leaking slowly, and couldn't cool the engine after a while, even when it was full of coolant.
If you don't show any of these symptoms, first change the thermostat, it's cheap and easy and they go bad often. Then fill the radiator, and while the engines running, look in the radiator neck to see if water's moving through it. Maybe it's clogged, but probably not, chances are pump or thermostat in my experience.
Anyway, that's a start which includes some things I did to mine when I had similar problems. Let me know.