all right I have a 1995 Dodge caravan and it overheats in different ways at random. When I start it and drive it around a few minutes the needle on the gauge will shoot all the way over to the highest temp and the light will come on. If I turn the engine off and then turn it back on, the temp will be fine until I start driving again. Eventually, after about 7 minutes of driving the needle will suddenly shoot down to normal operating temps. I changed the thermostat but changed nothing. The radiator fan does not come on. When I took the line of to test the water pump, the coolant moved but only in periods. It would shoot out about 10 ounces every minute. I am not sure if this is the proper amount or if the coolant is supposed to run all the time. Another note is that when I drive it on a highway it will shoot up to about 3/4 on the temp gauge. It stays here except when I go up hills or accelerate a lot. Then it overheats.

Another thing is that I tried to wire the fan up to the battery. It comes on but the wires get hot. Today, I noticed vapor coming from the exhaust so I am hoping it is not a bad ordeal.

My experience is water pumps output is directly related to RPM. Try draining the system to see what's in it... any physical particals are a bad sign... you may have water pump failure. The fan is controlled by a heat sensing switch in the cooling system. Follow the wires back from the fan motor to it's relay, then from the relay back to the switch. One may test the switch with a multimeter, from cold start and again at operating temp to see if it "makes" on temp rise. Does the fan motor spin freely, or slowly "scrape" to a stopwhen gently spun by hand? Good luck...