Wally Kimble and I drove our wives to Newfoundland from Oregon several years ago. His then new '06 Patriot Thunder fan never stopped blowing. When I was in trail, I could see the road dust bellow out! I recall a discussion that the fan system consumed about 50 hp and the necessary fuel to keep it turning. It may have been a malfunction, but it seemed normal. Wally averaged about 6 to 6.5 mpg.