I bought a 78 f250 for $350 the truck was a mud truck and i have had to replace alot of things like brake booster, mc, starter, alt, power steering pump. But me and my friends have noticed this things gets hot really really fast. But the temp guage shows normal temp readings. So toda i drove it for about 20-25 min. Got home ran it on a little dirt hill in 4lo i wasnt holding it full throttle basically idling. Well it stalled and wouldnt start, popped the hood coolent was boiling out the overflow tube connection of the radiator. So i let it cool down for an hour before i had to go to work. I started it, started it right up, idled very smooth for about 10 sec then started running very very bad. So i had to move it about 30 feet and it basically would stop and go, i stopped look at the exhaust and some black smoke came out tried to rev it a little, nop wouldnt do that. So i shut it off; popped the hood and there was what i think was collent on top of the block boiling, and it was big puddles. So im thinking its the water pump or radiator not working. But you guys would probally know a little better than i would.

 

If you have means to test the cooling system pressure see if the pressure builds rapidly indicating a leaking head gasket etc. Otherwise check to make sure it has the proper thermostat. Water does not circulate properly in these engines without the proper thermostat. Just because a thermostat is in place does not mean it is the right one. Overheating so quickly is strange tho. Head gaskets in backwards or leaking head gaskets can also cause coolant overflow and leaks all over.