1997 Dodge Caravan the water pump or head gasket

[quote:29b0df1637="baldie"]Engine Cooling problem
1997 Dodge Caravan 6 cyl Front Wheel Drive Automatic 239000 miles

i have 1997 dodge caravan and it has over heated on me. was low on oil when it happened. since then it overheats when under load and over 2 to 2 and a half thou revs.. heats up quickly from cold but if you crack the rad cap open and release the pressure and loose a little fluid it will run a half temp most the time. but give it a little to much power and it will raise in temp again and then bring down the revs and will slowly hit half temp again.. thought it was a head gasket but there is no water in the oil and no loss of power and no smoke..?? i also notice that the heater is not working properly. I have eliminated the radiator and the thermostat so can anyone tell me what it is...[/quote:29b0df1637]

When you say that you have eliminated the thermostat, are you saying that you have replaced it? Even if it's not the problem, it wouldn't hurt to replace. I've also read that the heater will malfunction if the thermostat is stuck open. The radiator cap could also be at fault. Good luck.