Ford F-150 Owner's Manual page 331

If you drive in extremely hot climates:
• You can decrease the coolant
concentration to 40%.
• Coolant concentrations below 40%
decrease the freeze and corrosion
protection characteristics of the
coolant and may cause engine
damage.
Vehicles driven year-round in non-extreme
climates should use prediluted coolant for
optimum cooling system and engine
protection.
Coolant Change
At specific mileage intervals, as listed in
the scheduled maintenance information,
the coolant should be changed. Add
prediluted coolant approved to the correct
specification. See Capacities and
Specifications (page 384).
Fail-Safe Cooling
Fail-safe cooling allows you to temporarily
drive your vehicle before any incremental
component damage occurs. The fail-safe
distance depends on ambient
temperature, vehicle load and terrain.
How Fail-Safe Cooling Works
If the engine begins to overheat,
the coolant temperature gauge
moves toward the red zone:
A warning lamp illuminates and
a message may appear in the
information display.
If the engine reaches a preset
over-temperature condition, the engine
automatically switches to alternating
cylinder operation. Each disabled cylinder
acts as an air pump and cools the engine.
F-150 (TFC) Canada/United States of America, enUSA, Edition date: 201607, Second Printing
Maintenance
When this occurs, your vehicle still
operates, however:
• Engine power is limited.
• The air conditioning system turns off.
Continued operation increases the engine
temperature, causing the engine to
completely shut down. Your steering and
braking effort increases in this situation.
When the engine temperature cools, you
can re-start the engine. Have your vehicle
checked as soon as possible to minimize
engine damage.
When Fail-Safe Mode Is Activated
Fail-safe mode is for use during
emergencies only. Operate your
vehicle in fail-safe mode only as long
as necessary to bring your vehicle to rest
in a safe location and seek immediate
repairs. When in fail-safe mode, your
vehicle will have limited power, will not be
able to maintain high-speed operation, and
may completely shut down without
warning, potentially losing engine power,
power steering assist, and power brake
assist, which may increase the possibility
of a crash resulting in serious injury.
Never remove the coolant reservoir
cap when the engine is running or
hot.
Your vehicle has limited engine power
when in the fail-safe mode, drive your
vehicle with caution. Your vehicle does not
maintain high-speed operation and the
engine may operate poorly.
Remember that the engine is capable of
automatically shutting down to prevent
engine damage. In this situation:
1. Pull off the road as soon as safely
possible and switch the engine off.
328
WARNINGS