2000 Ford Ranger Overheating - bought new thermostat and still overheat's

Did you check the new thermostat? Used to be you kind of worked a new thermostat to make sure it would open and not shut closed. When selling Fords I cringed as a salesperson, I saw a new car going out with the gauge going towards hot - often car buyers are superstitious, and will not buy a car if they incur any problem before they drive it off the lot - so the salesperson would kill me if I pointed this out. But of course the car had a bad thermostat that was stuck shut, and the couple with their kids never got to where they were going - so a brand new thermostat can stick shut. You can always test one by placing in water on the stove, and monitor the temp you see it open at - it should open at whatever it is rated at - 180 degree's or whatever the rating is.