FORD 2012 F-550 v.2 - Manual (Page 383)

If you drive in extremely hot climates:
• It is still necessary to maintain the coolant concentration
above 40%.
• NEVER decrease the coolant concentration below 40%.
• Decreased engine coolant concentrations below 40% will
decrease the corrosion/freeze protection characteristics of the
engine coolant and may cause engine damage.
• If available, refer to the chart on the coolant container to
ensure the coolant concentration in your vehicle will provide
adequate protection at the temperatures in which you drive.
Vehicles driven year-round in non-extreme climates should use a 50/50
mixture of engine coolant and distilled water for optimum cooling system
and engine protection.
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.
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.
How fail-safe cooling works
If the engine begins to overheat:
• The engine coolant temperature gauge will move to the red (hot)
area.
• The message center 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.
Maintenance and Specifications
383
2012 F-250/350/450/550 (f23)
Owners Guide, 2nd Printing
USA (fus)