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If your vehicle is equipped with a diesel engine, refer to the
Maintenance product specifications and capacities section of your
diesel supplement.
Fill your engine coolant reservoir as outlined previously in the Adding
engine coolant section.
Severe climates
If you drive in extremely cold climates:
• It may be necessary to increase the coolant concentration
above 50%.
• NEVER increase the coolant concentration above 60%.
• A coolant concentration of 60% will provide improved freeze
point protection. Increased engine coolant concentrations
above 60% will decrease the overheat 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 freeze protection at the temperatures in which you
drive in the winter months.
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. Maintenance and Specifications
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Owners Guide, 4th Printing
USA (fus)
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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.
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: Never remove the coolant reservoir cap while the
engine is running or hot.
5. Re-start the engine and take your vehicle to an authorized dealer.
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.Maintenance and Specifications
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Owners Guide, 4th Printing
USA (fus)
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Engine fluid temperature management (except 6.8L V10)
Your vehicle has been designed to pull a trailer, but because of the added
load, the vehicle’s engine may temporarily reach higher temperatures
during severe operating conditions such as ascending a long or steep
grade while pulling a trailer in hot ambient temperatures.
At this time, you may notice your engine coolant temperature gauge
needle move toward the H and the POWER REDUCED TO LOWER
TEMP message may appear on the message center.
You may notice a reduction in the vehicle’s speed caused by reduced
engine power. Your vehicle has been designed to enter this mode if
certain high temperature/high load conditions take place in order to
manage the engine’s fluid temperatures. The amount of speed reduction
will depend on the vehicle loading, towing, grade, ambient temperature,
and other factors. If this occurs, there is no need to pull off the road.
The vehicle can continue to be driven while this message is active.
WARNING: To reduce the risk of collision and injury, be
prepared that the vehicle speed may reduce and the vehicle may
not be able to accelerate with full power until the fluid temperatures
reduce.
The air conditioning may also cycle on and off during severe operating
conditions to protect overheating of the engine. When the engine coolant
temperature decreases to a more normal operating temperature, the air
conditioning will turn on once again.
If you notice any of the following:
• the engine coolant temperature gauge moves fully into the red (hot)
area
• the coolant temperature warning light illuminates
• the service engine soon indicator illuminates
1. Pull off the road as soon as safely possible and place the vehicle in P
(Park).
2. Leave the engine running until the coolant temperature gauge needle
moves away from the H range. After several minutes, if this does not
happen, follow the remaining steps.
3. Turn the engine off and wait for it to cool before checking the coolant
level. Maintenance and Specifications
381
2011 F-250/350/450/550 (f23)
Owners Guide, 4th Printing
USA (fus)