I had two mounted in the bed of my old mini and drove it all the time in the rain, never had a problem, BUT maybe I just got lucky? I'm sure you would be fine since they are "sealed".. just don't submerge them in water.. haha.
i heard that at a show like sema or something like that they dropped a viair in a fishtank full of water and it ran under water. so they are very water proof. any viair reps out there that can confirm this?
as long as the filters are remote mounted and the wiring is sealed those bitches pump under water! my boy had his mounted under his f-150 and they would kick on while he was dumping his jet ski! i guess its one way to cool them! hahaha
aslong as they are sealed type, and make sure that you locate the filters so that it dont suck any water in. if any gets in they stop pumping. i have had mine under the truck with the filter relocated with the line they give you and for years they been fine drivein it every day
my viair 460 was mounted in the bed of my mazda before i bought it the truck sat for a year getting rained on when i got the truck the comp was did not work the motor was no good