[Danr55]

I presume you have an electric fan. If it's a polar type fan do you have a shroud around it? If you don't then you need to put a shroud around it so the air flow comes over the radiator and not around it from the back. What kind of radiator are you running? How many cores does it have? And what's the capacity? as you can see I'm from Arizona and we pay special attention to things like overheating.