The advertised fuel capacity of the fuel tank(s) on your vehicle is equal
to the rated refill capacity of the fuel tank(s) as listed inRefill
capacitiesin this chapter. The advertised capacity is the amount of the
indicated capacity and the empty reserve combined. Indicated capacity is
the difference in the amount of fuel in a full tank and a tank when the
fuel gauge indicates empty. Empty reserve is the small amount of usable
fuel remaining in the fuel tank after the fuel gauge indicates empty.
The amount of empty reserve varies and should not be relied
upon to increase driving range. When refueling your vehicle after
the fuel gauge indicates empty, you might not be able to refuel
the full amount of the advertised capacity of the fuel tank due to
the empty reserve still present in the tank.
Filling the tank
For consistent results:
•Use the same fill rate setting (low-medium-high) each time during
filling.
•Allow three automatic click-offs when filling.
•Always use fuel of a known quality, preferably a national brand.
•Have the vehicle loading and distribution the same every time.
•When refueling a vehicle equipped with dual fuel tanks, if the two
tanks are not filled equally, the fuel gauge reading may fluctuate
slightly until the fuel level between the two tanks balance out and
become equal.
Your results will be most accurate if your filling method is consistent.
Note:For vehicles equipped with dual fuel tanks, engine performance
may degrade if fuel is not added to both tanks when refueling.
Calculating fuel economy
1. Fill the fuel tank(s) completely and record the initial odometer
reading (in miles or kilometers).
2. Each time you fill the tank(s), record the amount of fuel added (in
gallons or liters).
3. After at least three to five tank fill-ups, fill the fuel tank(s) and record
the current odometer reading.
4. Subtract your initial odometer reading from the current odometer
reading.
Maintenance and Specifications
208
2011 F-650/750(f67)
Supplement, 2nd Printing
USA(fus)
