I just bought a 1994 chrysler LHS and the person i bought it from said it had an overheating problem. the first 24 hours i had it, i drove probably 10-20 miles and had no issues, after installing a thermostat and an AC belt, it was overheating every 5 miles or so. Today, while working on it. i noticed a gnarly coolant leak. i really dont want to have to replace the water pump, but can if needed. However when i tried to bleed the thermostat yesterday, nothing came out besides some steam and then all air.
anyone know what my issue is or have had the same?
it is a 3.5L engine.

 

There can be many causes of overheating including bad thermostat, thermostat installed backwards, clogged radiator (internal or external) collapsed hose, wrong or insufficient coolant, bad radiator cap, broken water pump, non-functional fan(s), blown head gasket and probably some more that I have forgotten about.
The best approach is to eliminate each possible cause by testing or replacing parts, starting with the cheap and easy stuff first, and working toward the expensive stuff if necessary. The car is 22 years old and almost an antique vehicle, so it's going to have problems.