help with over heating

Did it overheat before you added the homemade shroud? If the shroud is too deep into the fan blade it can reduce the effectiveness of the fans ability top draw air through the radiator. I think you want at least 3/4" of fan blade sticking outside of the shroud area. Post some pics of your setup.

Just re-read your post before I actually posted mine. Sounds like you have an electric fan. My comments were for a stock fan setup so may not apply to you. Post a few pics anyway maybe someone can spot a problem for you.