Originally Posted by CHUCK
heard of some having problems in the winter with rain water or snow making through the air inlet side..onto the filter element, and freezing/stopping it up...be it the Napa 6637 or the stock enclosed air box. I think ford sales a cover for the grille though. I wouldnt worry about it till it actually happens. No reason not to run the Napa 6637 filter.....like I said, happened to stock air intakes too. Its rare...
What you said is exactly what i was worried about, since it did happen to me last year in a bad storm with my stock airbox, i might just keep a spare one in the truck for the long trips... just in case.