Ford F-150 2010 Owner's Manual page 377

How fail-safe cooling works
If the engine begins to overheat:
• The engine coolant temperature gauge will move to the red (hot)
area.
• The mini message center (if equipped) will indicate "Check Gauges",
refer to Warning lights and chimes in the Instrument Cluster
chapter.
• The
light 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:
• The engine will completely shut down.
• Steering and braking effort will 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
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 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.
WARNING: 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.
Maintenance and Specifications
377