Ive been on here a couple times complaining about my mpg's. Well to my surprise I took off my WF outa curiosity and picked up 1.2 MPG on a known 120mi run that Ive tested on several times this week. 06cc 4wd W 35 x 12.5 Bfg's 18.2 MPG at 72mph W plow frame hangin down, no bed cover, no load. With WF on temp was 210, WO/WF 185 and slightly more "pingy" sounding, Adequate cab heat. Im guessing this is due to the fan clutch staying unlocked.