I used to have problems from stopping the car overheating in the summer. I used a waterless coolant for a couple of years after a friend got me some, (Not sure if it was the Evans one or another make) but it's not freely available here.
After replacing the radiator with one from Arrow Rads in the UK and using a lower temp thermostat and fan switch, don't remember where they came from, possibly Rodney Dickman's or possibly the Fiero Store. I have switched back to the normal green stuff and temps never get much above 1/4 before fans kick in. ( I also needed to replace 1 of the fans).
Now I can use the car in the summer here in the Middle East, OAT 40C+ and it still stays cool
However the air con is not good and I hate driving with the roof up, so I overheat before the car does.
Recently found some of the small bore coolant hose elbows that go to the throttle body plugged. Cleaning them out has reduced under bonnet temps a lot.