I ran my red & white truck for more than a year without a cooling fan at all. The only fallout I had was you had to pay attention to when you could run the a/c. If it was really hot out you could not just let it idle with the a/c on blast, but as long as you were moving at 10+ MPH, no problems. I did tow with my truck without a fan, but nothing super heavy (drag car and trailer but flat ground), and in the end I did install a Taurus electric fan which worked pretty well.
The mechanical fan moves a lot of air and I would highly recommend it if you are going to work your truck hard. I was experimenting and I did get measurably better mileage without the fan, but you can do that with your right foot too. If I had it to do all over again I'd do the workhorsecustoms electric fan kit as I think that's the best of both worlds.
