well, yes. You will be chilling the water and blowing room temp air across it, which will in turn get colder as it exits the radiator. The catch... is condensation will form and drip all over the place. Figure out a way to capture the condensation.
Then your waterblock will do this:



No, i am kidding. It will not frost over (without an actually chiller unit) and it will not spontaniously carve my nickname into the frost. But when you start doing the crazy things this thread encourages, you will get condensation.