Since the new station right down the road 1.5 miles from my yard went in, with it's truck stop style dual pumping stations, I've been playing around with checking my fuel usage. 63 mph on the freeway, 5.5 MPG, which I remember from when I drove it back from Wisconsin when I bought it. But the latest check up really surprised me: I filled both tanks, drove the 1.5 mile to my shop, the next morning drove 1 mile further to my job (a rare close job) and than swung trusses from 7 to 2, with the engine on constantly. Then I drove back to the station, used the same pumps, and the same method to fill it.
So, with 7 hrs. of working it, and 5 miles of 45 mph driving, no stops. LESS THAN 7 GALLONS OF DIESEL USED! 6.89 gallons. I was as exact as can be in how I determined it "filled", same flow rate, same foaming to same point in the filler neck, but even with a 25% error factor, that is still pretty amazing to me. I will NOT tell my customers this, none of their business, I do tell them about the 5.5 MPG though! 425 HP Mack. I was guesstimating more like 3-5 GPH for some reason....but since the vast majority of my work involves mountainous travel time, the on the road MPG was a known, the working it GPH not so much. Let's call it 12 gallons AT MOST (25% error), still only 1.7 GPH. If the 6.89 was accurate, about 1 GPH. Good news, with the fuel prices these days, $3.93 here.