my car is a 1991 caprice, i recently just put a new 350 motor in it, and it is running hot, i put a new thermostat but i didnt put any coolant , i just put lots of water,...i think it might be the radiator hose or my water pump...
Water is ok during summer time, replacing the water pump is a good idea, if you have the money get a large radiator and change the whole system. changing oil more often helps to cool down your engine too.
it not the hose unless it stopped up or leaking it prolly not the water pump unless the weap holes are leaking maybe your thermostat is stuck shut, you could have blown head gaskets or cracked heads or block that makes it run hot to, it does have to mix oil in the water to be cracked you can do a compression test on the coolent system.
you have to have a mixture of coolant in it or it will run hot,it will also rust the inside of the engine up real bad,and cause it to scale off rust particles,which in time may cause the radiator to stop up on it,it needs a 50/50 mix at least in it ,plain water will boil a lot faster and evaporate,i suggest you use a mix of coolant in it,that may be the problem with it,good luck on it.
because your fan cltch is running does not mean its not bad, it could be slipping and not rotating fast enough, also depending on the miles of the car you could have a clogged up cat converter, and that will make it run hot also