Car normally over heats. Possible that previous owner put additive in radiator?

Temperature gauge will read less than 50%. I had a leak once and NO liquid in overflow tank. The car was very hot, but the gauge did not indicate this. It remained under 50%. So what are you considering?

Best bet is to have a scan tool hooked up so live data can be viewed to see what the actual engine temperature is! Then it an be compared to the gauge reading to check the accuracy of the gauge... IF both readings correspond and guage reading is not HOT..... No worries!... The hot engine smell is more likely to be caused by something else... Oil leakage onto hot exhaust perhaps...

I rarely drive the car because I am afraid of what will happen. Replacing the radiator is a great idea! What else would I need to replace along with that? Hoses, etc.? What about the heater core? I have no idea of what the expense would be, but it only has 127,000 miles. A new kit was put in transmission not many miles ago, but I suppose one time HOT would be enough.