What You Should Know About Fail-Safe Cooling; How Fail-Safe Cooling Works - Ford Super Duty Owner's Manual

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If you drive in extremely hot climates:
• It may be necessary to have a Ford authorized dealer decrease the
coolant concentration to 40%.
• A coolant concentration of 40% will provide improved overheat
protection. Engine coolant concentrations below 40% will decrease the
corrosion and freeze protection characteristics of the engine coolant
and may cause engine damage.
Vehicles driven year-round in non-extreme climates should use
prediluted engine coolant for optimum cooling system and engine
protection.
What You Should Know About Fail-Safe Cooling (If Equipped)
WARNING: If fail-safe cooling activates, pull off the road as soon
as safely possible and turn the engine off. The engine may
automatically shut off while driving without further indication.
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 information display will indicate the engine is overheating.
• 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 restarted. Take
your vehicle to an authorized dealer as soon as possible to minimize
engine damage.
2013 F-250/350/450/550 (f23)
Owners Guide gf, 2nd Printing, December 2012
USA (fus)
Maintenance