Most efans are sealed that i know? I mean their in front of the grill, you sit behind a water misting semi in a drenching rain for 10 miles and the fans are going to be absolutely soaked. I don't see any reason why they wouldn't river cross unless the water density would burn out the motors. Then agian I'd think the density of water on a mechanical fan would bend blades and shaft or tear belt. I still am putting efans on my expy when I get the $$$ unless someone can point out a deficiency.