Not too long ago, I bought a 1996 Mustang GT V8. Everything is perfect despite this annoying heating problem that I can't seem to figure out what the problem is. It only overheats during very hot weather and turning the AC makes it overheat even worse. Whenever it got really bad, the antifreeze would POUR out of the bottom, but we have inspected everything and can't seem to find where it's coming out of. So, I have put in a new thermostat because the older one wasn't working as well anymore. That didn't fix the problem. Then, we put in a new 16" radiator fan, because the previous owner put in two 10" fans that didn't seem to be cooling the engine down enough. Unfortunately, the new fan hasn't completely fixed the problem. Can anyone PLEASE give me an idea as to what it could be?
Also, it idles kind of rough at times, and sometimes it feels like the car is going to shut off when the RPMs get too low. Any ideas as to what that could be?
Thanks!

 

It sounds as though the radiator is clogged--get it flow tested at a radiator shop--or just buy a new one as they do not cost that much, $90 to $130 at RockAuto.

Idle problems are generally caused by a bad IAC...

 

Alright thanks for your help! I'll try that

 

With the engine cold, remove the overflow cap, and run the engine. When at full operating temperature look for water flow inside the coolant bottle. You should see a good amount of water flow in the bottle. If not, id suggest removing the water pump, and checking the impeller.

 

Thanks for the ideas I will try it tomorrow. Thanks, Mick