FORD 2013 Flex v.4 - Manual (Page 200)

3.5L V6 EcoBoost® engine
“Regular” unleaded gasoline with a pump (R+M)/2 octane rating of 87 is
recommended. Some stations offer fuels posted as “Regular” with an
octane rating below 87, particularly in high altitude areas. Fuels with
octane levels below 87 are not recommended. Premium fuel will provide
improved performance and is recommended for severe duty usage such
as trailer tow.
Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily while you are using fuel with the recommended octane
rating, see your authorized dealer to prevent any engine damage.
RUNNING OUT OF FUEL
Avoid running out of fuel because this situation may have an adverse
effect on powertrain components.
If you have run out of fuel:
• You may need to cycle the ignition from off to on several times after
refueling to allow the fuel system to pump the fuel from the tank to
the engine. On restarting, crank time will be a few seconds longer
than normal. With keyless ignition, just start the engine. Crank time
will be longer than usual.
• Normally, adding 1 gallon (3.8 liters) of fuel is enough to restart the
engine. If the vehicle is out of fuel and on a steep grade, more than
1 gallon (3.8 liters) may be required.
• The service engine soon indicator may come on. For more information
on the service engine soon indicator, see Warning Lamps and
Indicators in the Instrument Cluster chapter.
Refilling with a Portable Fuel Container
WARNING: Do not insert the nozzle of a portable fuel container or
aftermarket funnel into the capless fuel system. This could damage
the fuel system and its seal, and may cause fuel to run onto the ground
instead of filling the tank, which could result in serious personal injury.
WARNING: Do not try to pry open or push open the capless fuel
system with foreign objects. This could damage the fuel system
and its seal and cause injury to you or others.
Note: Do not use aftermarket funnels; they will not work with the
capless fuel system and can damage it. The included funnel has been
specially designed to work safely with your vehicle.
Fuel and Refueling 199
2013 Flex (471)
Owners Guide gf, 4th Printing, December 2012
USA (fus)