In Florida, your probably OK, but up here in northern IL where we can get cold weather in the winters, anything driven year around needs to run through the bottom of the radiator. Even with just the cooler in the bottom of the rad, the RE46 in my truck doesn't like to shift well until it runs enough to get the fluid temp up some when its cold like it was around Christmas this year. Once it got warmed up a bit, it worked great.