The total bill just for adding AdBlue? A stunning $316.99. We were down to 18 percent full on the additive at 16,566 miles. It took 7.5 gallons to fill the tank, costing an eye-opening $241.50 for the fluid alone. The labor to add the fluid plus tax accounted for the rest. None of this was covered by the warranty… At the current rate and cost of consumption, just the AdBlue itself (without the labor, which would probably be included as part of the routine service) would cost $1,457.80 for 100,000 miles of driving. That's a lot of money, knocking about a third off of your fuel savings vs. buying a GL450 V8.