Page 321 of 358

What you should know about fail-safe cooling (if equipped)
If the engine coolant supply is depleted, this feature allows the vehicle to
be driven temporarily before incremental component damage is incurred.
The “fail-safe” distance depends on ambient temperatures, vehicle load
and terrain.
How fail-safe cooling works
If the engine begins to overheat:
•The engine coolant temperature gauge will move to the red (hot)
area.
•The coolant temperature warning light
will illuminate.
•The service engine soon
indicator will illuminate.
If the engine reaches a preset over-temperature condition, the engine
will automatically switch to alternating cylinder operation. Each disabled
cylinder acts as an air pump and cools the engine.
When this occurs the vehicle will still operate. However:
•The engine power will be limited.
•The air conditioning system will be disabled.
Continued operation will increase the engine temperature and the engine
will completely shut down, causing steering and braking effort to
increase.
Once the engine temperature cools, the engine can be re-started. Take
your vehicle to a service facility as soon as possible to minimize engine
damage.
When fail-safe mode is activated
You have limited engine power when in the fail-safe mode, so drive the
vehicle with caution. The vehicle will not be able to maintain high-speed
operation and the engine will run rough. Remember that the engine is
capable of completely shutting down automatically to prevent engine
damage, therefore:
1. Pull off the road as soon as safely possible and turn off the engine.
2. Arrange for the vehicle to be taken to a service facility.
3. If this is not possible, wait a short period for the engine to cool.
4. Check the coolant level and replenish if low.
Maintenance and Specifications
321
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 322 of 358

WARNING:Never remove the coolant reservoir cap while the
engine is running or hot.
5. Re-start the engine and take your vehicle to a service facility.
Driving the vehicle without repairing the engine problem
increases the chance of engine damage. Take your vehicle to a
service facility as soon as possible.
FUEL FILTER
Your vehicle is equipped with a lifetime fuel filter that is integrated with
the fuel tank. Regular maintenance or replacement is not needed.
WHAT YOU SHOULD KNOW ABOUT AUTOMOTIVE FUELS
Important safety precautions
WARNING:Do not overfill the fuel tank. The pressure in an
overfilled tank may cause leakage and lead to fuel spray and fire.
WARNING:The fuel system may be under pressure. If you hear
a hissing sound near the fuel filler door (Easy Fuel™ “no cap”
fuel system), do not refuel until the sound stops. Otherwise, fuel may
spray out, which could cause serious personal injury.
WARNING:Automotive fuels can cause serious injury or death
if misused or mishandled.
WARNING:Gasoline may contain benzene, which is a
cancer-causing agent.
Observe the following guidelines when handling automotive fuel:
•Extinguish all smoking materials
and any open flames before
refueling your vehicle.
•Always turn off the vehicle before
refueling.
Maintenance and Specifications
322
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 323 of 358

•Automotive fuels can be harmful or fatal if swallowed. Fuel such as
gasoline is highly toxic and if swallowed can cause death or permanent
injury. If fuel is swallowed, call a physician immediately, even if no
symptoms are immediately apparent. The toxic effects of fuel may not
be visible for hours.
•Avoid inhaling fuel vapors. Inhaling too much fuel vapor of any kind
can lead to eye and respiratory tract irritation. In severe cases,
excessive or prolonged breathing of fuel vapor can cause serious
illness and permanent injury.
•Avoid getting fuel liquid in your eyes. If fuel is splashed in the eyes,
remove contact lenses (if worn), flush with water for 15 minutes and
seek medical attention. Failure to seek proper medical attention could
lead to permanent injury.
•Fuels can also be harmful if absorbed through the skin. If fuel is
splashed on the skin and/or clothing, promptly remove contaminated
clothing and wash skin thoroughly with soap and water. Repeated or
prolonged skin contact with fuel liquid or vapor causes skin irritation.
•Be particularly careful if you are taking “Antabuse” or other forms of
disulfiram for the treatment of alcoholism. Breathing gasoline vapors,
or skin contact could cause an adverse reaction. In sensitive
individuals, serious personal injury or sickness may result. If fuel is
splashed on the skin, promptly wash skin thoroughly with soap and
water. Consult a physician immediately if you experience an adverse
reaction.
WARNING:When refueling always shut the engine off and
never allow sparks or open flames near the filler neck. Never
smoke while refueling. Fuel vapor is extremely hazardous under certain
conditions. Care should be taken to avoid inhaling excess fumes.
WARNING:The flow of fuel through a fuel pump nozzle can
produce static electricity, which can cause a fire if fuel is
pumped into an ungrounded fuel container.
Maintenance and Specifications
323
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 324 of 358

Refueling
WARNING:Fuel vapor burns violently and a fuel fire can cause
severe injuries. To help avoid injuries to you and others:
•Read and follow all the instructions on the pump island;
•Turn off your engine when you are refueling;
•Do not smoke if you are near fuel or refueling your vehicle;
•Keep sparks, flames and smoking materials away from fuel;
•Stay outside your vehicle and do not leave the fuel pump unattended
when refueling your vehicle — this is against the law in some places;
•Keep children away from the fuel pump; never let children pump
fuel.
Use the following guidelines to avoid electrostatic charge build-up when
filling an ungrounded fuel container:
•Place approved fuel container on the ground.
•DO NOT fill a fuel container while it is in the vehicle (including the
cargo area).
•Keep the fuel pump nozzle in contact with the fuel container while
filling.
•DO NOT use a device that would hold the fuel pump handle in the fill
position.
Easy Fuel™ “no cap” fuel system
Your fuel tank is equipped with an Easy Fuel™ “no cap” fuel filler
system. This allows you to simply open the fuel filler door and insert the
fuel filler nozzle into the fuel system. The Easy Fuel™ system is
self-sealing and protected against dust, dirt, water and snow/ice.
When fueling your vehicle:
1. Turn the engine off.
2. Open the fuel filler door.
3. Slowly insert the fuel filler nozzle fully into the fuel system. Pump fuel
as normal.
4. After you are done pumping fuel, wait about five seconds before
slowly removing the fuel filler nozzle. This allows residual fuel to drain
back into the fuel tank and not spill onto the vehicle.
Maintenance and Specifications
324
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 325 of 358

Note:A fuel spillage concern may occur if overfilling the fuel tank. Do
not overfill the tank to the point that the fuel is able to bypass the fuel
filler nozzle. The overfilled fuel may run down the drain located within
the fuel filler housing and to the ground.
If the Check Fuel Fill Inlet message comes on, the fuel fill inlet may not
have properly closed. The inlet may have stuck open or debris may be
preventing the inlet from fully closing. At the next opportunity, safely
pull off the road, turn off the engine, open the fuel filler door and
remove any visible debris from the fuel fill opening. Insert either the fuel
fill nozzle or the fuel fill funnel (seeRefilling with a portable fuel
containerfor funnel location) provided with the vehicle several times to
dislodge any debris and/or allow the inlet to close properly. If this action
corrects the problem, the Check Fuel Fill Inlet message may not reset
immediately. It may take several driving cycles for the Check Fuel Fill
Inlet message to turn off. A driving cycle consists of an engine start-up
(after four or more hours with the engine off) followed by city/highway
driving. Continuing to drive with the Check Fuel Fill Inlet message on
may cause the service engine soon lamp to turn on as well.
WARNING:The fuel system may be under pressure. If you hear
a hissing sound near the fuel filler door (Easy Fuel™ “no cap”
fuel system), do not refuel until the sound stops. Otherwise, fuel may
spray out, which could cause serious personal injury.
Choosing the right fuel
Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded
fuel or any other fuel. The use of leaded fuel is prohibited by law and
could damage your vehicle.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based additives.
Note:Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.
Octane recommendations
3.7L V6 engine
Your vehicle will run normally on 87 octane regular fuel. Premium fuel
will provide improved performance.
Maintenance and Specifications
325
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 326 of 358

3.5L V6 EcoBoost engine
Your vehicle is designed to run on regular fuel with an octane rating of
87 or higher. For best overall performance, premium fuel with an octane
rating of 91 or higher is recommended. The performance gained by using
premium fuel will be most noticeable in hot weather or in severe duty
applications such as towing a trailer.
Some stations offer fuels posted as
Regularwith an octane rating
below 87, particularly in high
altitude areas. Fuels with octane
levels below 87 are not
recommended for either engine. 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.
Fuel quality
If you are experiencing starting, rough idle or hesitation driveability
problems, try a different brand of unleaded gasoline. If the problems
persist, see your dealer or a qualified service technician.
It should not be necessary to add any aftermarket products to your fuel
tank if you continue to use high quality fuel of the recommended octane
rating. Aftermarket products could cause damage to the fuel system.
Repairs to correct the effects of using an aftermarket product in your
fuel may not be covered by your warranty.
Many of the world’s automakers approved the World-Wide Fuel Charter
that recommends gasoline specifications to provide improved
performance and emission control system protection for your vehicle.
Gasolines that meet the World-Wide Fuel Charter should be used when
available. Ask your fuel supplier about gasolines that meet the
World-Wide Fuel Charter.
Cleaner air
Ford endorses the use of reformulated “cleaner-burning” gasolines to
improve air quality.
Running out of fuel
Avoid running out of fuel because this situation may have an adverse
effect on powertrain components.
87(R+M)/2 METHOD
Maintenance and Specifications
326
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 327 of 358

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, cranking time will take a few seconds longer
than normal.
•Normally, adding 1 gallon (3.8L) of fuel is enough to restart the
engine. If the vehicle is out of fuel and on a steep grade, more than
1 gallon (3.8L) may be required.
•The service engine soon
indicator may come on. For more
information on the service engine soon indicator, refer toWarning
lights and chimesin theInstrument Clusterchapter.
Refilling with a portable fuel container
With the Easy Fuel™ “no cap” fuel system, use the following directions
when filling from a portable fuel container:
WARNING:Do not insert the nozzle of portable fuel containers
or aftermarket funnels into the Easy 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 Easy
Fuel™ system with foreign objects. This could damage the fuel
system and its seal and cause injury to you or others.
When filling the vehicle’s fuel tank from a portable fuel container, use the
funnel included with the vehicle.
1. After lifting the trunk cargo
cover, locate the white plastic
funnel. It is attached to the rear,
lower edge of the spare tire
compartment.
Maintenance and Specifications
327
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)
Page 328 of 358

2. Slowly insert the funnel into the
Easy Fuel™ system.
3. Fill the vehicle with fuel from the portable fuel container.
4. When done, clean the funnel or properly dispose of it. Extra funnels
can be purchased from your authorized dealer if you choose to dispose
of the funnel.Do notuse aftermarket funnels; they will not work with
the Easy Fuel™ system and can damage it. The included funnel has
been specially designed to work safely with your vehicle.
ESSENTIALS OF GOOD FUEL ECONOMY
Measuring techniques
Your best source of information about actual fuel economy is you, the
driver. You must gather information as accurately and consistently as
possible. Fuel expense, frequency of fill-ups or fuel gauge readings are
NOT accurate as a measure of fuel economy. We do not recommend
taking fuel economy measurements during the first 1,000 miles
(1,600 km) of driving (engine break-in period). You will get a more
accurate measurement after 2,000 miles–3,000 miles (3,000 km–5,000
km).
Filling the tank
The advertised fuel capacity of the fuel tank on your vehicle is equal to
the rated refill capacity of the fuel tank as listed in theMaintenance
product specifications and capacitiessection of 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 fuel remaining in the fuel
tank after the fuel gauge indicates empty.
Maintenance and Specifications
328
2010 MKS(mks)
Owners Guide(own2002), 1st Printing
USA(fus)