FORD f150 - Manual (Page 244)

What You Should Know About Fail-
Safe Cooling
If you deplete the engine coolant supply,
this feature allows you to temporarily drive
your vehicle before you incur incremental
component damage. 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 and:
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
• this will disable the air conditioning
system.
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 an authorized dealer as soon as possible
to minimize engine damage.
When Fail-Safe Mode Is Activated
WARNINGS
Fail-safe mode is for use during
emergencies only. Operate the
vehicle in fail-safe mode only as long
as necessary to bring the vehicle to rest in
a safe location and seek immediate repairs.
When in fail-safe mode, the 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 while the engine is running or hot.
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. Have your vehicle towed to an
authorized dealer
3. If this is not possible, wait a short
period for the engine to cool.
4. Check the coolant level and replenish
if low.
5. Re-start the engine and take your
vehicle to an authorized dealer.
Note: Driving the vehicle without repairing
the engine problem increases the chance of
engine damage. Take your vehicle to an
authorized dealer as soon as possible.
242
F150 (TF6)
Maintenance