2021 FORD F-550 engine overheat

•
Your vehicle's brake system and the
trailer brake system work
independently of each other. Changing
the gain setting on the controller does
not affect the operation of your
vehicle's brakes.
• When you switch the engine off, the
controller output is disabled and the
display and module shut down.
Trailer Lamps WARNING: Never connect any
trailer lamp wiring to the vehicle's tail
lamp wiring; this may damage the
electrical system resulting in fire. Contact
your authorized dealer as soon as
possible for assistance in proper trailer
tow wiring installation. Additional
electrical equipment may be required.
Trailer lamps are required on most towed
vehicles. Make sure all running lights, brake
lights, turn signals and hazard lights are
working.
Before Towing a Trailer
Practice turning, stopping and backing up
to get the feel of your vehicle-trailer
combination before starting on a trip.
When turning, make wider turns so the
trailer wheels clear curbs and other
obstacles.
When Towing a Trailer
• Check your hitch, electrical connections
and trailer wheel lug nuts thoroughly
after you have traveled 50 mi (80 km).
• Do not drive faster than
70 mph
(113 km/h) during the first 500 mi
(800 km).
• Do not make full-throttle starts. •
When stopped in congested or heavy
traffic during hot weather, place the
gearshift in park (P) to aid engine and
transmission cooling and to help A/C
performance.
• Turn off the speed control with heavy
loads or in hilly terrain. The speed
control may turn off automatically
when you are towing on long, steep
grades.
• Shift to a lower gear when driving down
a long or steep hill. Do not apply the
brakes continuously, as they may
overheat and become less effective.
• If your transmission is equipped with a
Grade Assist or Tow/Haul feature, use
this feature when towing. This provides
engine braking and helps eliminate
excessive transmission shifting for
optimum fuel economy and
transmission cooling.
• If your vehicle is equipped with
Adaptive Steering and you have
enabled Tow/Haul, the Adaptive
Steering system adjusts the steering
response to match your vehicle ’s load.
The system reduces vehicle sensitivity
to steering inputs at higher vehicle
speeds while it maintains the ease of
parking and maneuverability at low
speeds.
• If your vehicle is equipped with
AdvanceTrac with RSC, this system
may turn on during typical cornering
maneuvers with a heavily loaded trailer.
This is normal. Turning the corner at a
slower speed while towing may reduce
this tendency.
• If you are towing a trailer frequently in
hot weather, hilly conditions, at the
gross combined weight rating (or any
combination of these factors), consider
refilling your rear axle with synthetic
gear lubricant (if the axle is not already
filled with it). See
Capacities and
Specifications (page 441).
313
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Towing

To top up the coolant level do the
following:
1. Unscrew the cap slowly. Any pressure
escapes as you unscrew the cap.
2. Add prediluted coolant meeting the correct specification. See Scheduled
Maintenance (page 565).
3. Add enough prediluted coolant to reach the correct level.
4. Replace the coolant reservoir cap. Turn
the cap clockwise until it contacts the
hard stop.
5. Check the coolant level in the coolant reservoir the next few times you drive
your vehicle.
Do not mix different colors or types of
prediluted coolant in your vehicle. Mixing
of prediluted coolant or using an incorrect
prediluted coolant may harm the engine
or cooling system components and may
not be covered by the vehicle Warranty.
If you have to add more than
1.1 qt (1 L) of
engine coolant per month, have your
vehicle checked as soon as possible.
Operating an engine with a low level of
coolant can result in engine overheating
and possible engine damage.
In case of emergency, you can add a large
amount of water without prediluted
coolant in order to reach a vehicle service
location. On arrival do the following:
1. Drain the cooling system.
2. Chemically clean the cooling system. We recommend Motorcraft Premium
Cooling System Flush.
3. Refill with prediluted coolant as soon as possible.
Water alone, without prediluted coolant,
can cause engine damage from corrosion,
overheating or freezing. Do not use the following as a coolant
substitute:
•
Alcohol.
• Methanol.
• Brine.
• Any coolant mixed with alcohol or
methanol antifreeze.
Alcohol and other liquids can cause engine
damage from overheating or freezing.
Do not add extra inhibitors or additives to
the coolant. These can be harmful and
compromise the corrosion protection of
the coolant.
Recycled Coolant
We do not recommend the use of recycled
coolant as an approved recycling process
is not yet available.
Dispose of used engine coolant in an
appropriate manner. Follow your
community ’s regulations and standards
for recycling and disposing of automotive
fluids.
Severe Climates
If you drive in extremely cold climates:
• It may be necessary to increase the
coolant concentration above 50%.
• A coolant concentration of 60%
provides improved freeze point
protection. Coolant concentrations
above 60% decrease the overheat
protection characteristics of the
coolant and may cause engine
damage.
365
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

If you drive in extremely hot climates:
•
It may be necessary to decrease the
coolant concentration to 40%.
• A coolant concentration of 40%
provides improved overheat
protection. Coolant concentrations
below 40% decrease the freeze and
corrosion protection characteristics of
the coolant and may cause engine
damage.
Vehicles driven year-round in non-extreme
climates should use prediluted coolant for
optimum cooling system and engine
protection.
Fail-Safe Cooling
Fail-safe cooling allows you to temporarily
drive your vehicle before any incremental
component damage occurs. The fail-safe
distance depends on ambient
temperature, vehicle load and terrain.
How Fail-Safe Cooling Works
If the engine begins to overheat, the
coolant temperature gauge moves toward
the red zone: A warning lamp illuminates and
a message may appear in the
information display.
If the engine reaches a preset
over-temperature condition, the engine
automatically switches to alternating
cylinder operation. Each disabled cylinder
acts as an air pump and cools the engine.
When this occurs, your vehicle still
operates, however:
• Engine power is limited.
• The air conditioning system turns off. Continued operation increases the engine
temperature, causing the engine to
completely shut down. Your steering and
braking effort increases in this situation.
When the engine temperature cools, you
can re-start the engine. Have your vehicle
checked as soon as possible to minimize
engine damage.
When Fail-Safe Mode Is Activated
WARNING: Fail-safe mode is for
use during emergencies only. Operate
your vehicle in fail-safe mode only as
long as necessary to bring your vehicle
to rest in a safe location and seek
immediate repairs. When in fail-safe
mode, your 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. WARNING:
Do not remove the
coolant reservoir cap when the engine is
on or the cooling system is hot. Wait 10
minutes for the cooling system to cool
down. Cover the coolant reservoir cap
with a thick cloth to prevent the
possibility of scalding and slowly remove
the cap. Failure to follow this instruction
could result in personal injury.
Your vehicle has limited engine power
when in the fail-safe mode, drive your
vehicle with caution. Your vehicle does not
maintain high-speed operation and the
engine may operate poorly.
Remember that the engine is capable of
automatically shutting down to prevent
engine damage. In this situation:
1. Pull off the road as soon as safely possible and switch the engine off.
366
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

2. If you are a member of a roadside
assistance program, we recommend
that you contact your roadside
assistance service provider.
3. If this is not possible, wait a short period for the engine to cool.
4. Check the coolant level. If the coolant level is at or below the minimum mark,
add prediluted coolant immediately.
5. When the engine temperature cools, you can re-start the engine. Have your
vehicle checked as soon as possible to
minimize engine damage.
Note: Driving your vehicle without repair
increases the chance of engine damage.
Engine Coolant Temperature
Management (If Equipped) WARNING:
To reduce the risk of
crash and injury, be prepared that the
vehicle speed may reduce and the
vehicle may not be able to accelerate
with full power until the coolant
temperature reduces.
If you tow a trailer with your vehicle, the
engine may temporarily reach a higher
temperature during severe operating
conditions, for example ascending a long
or steep grade in high ambient
temperatures.
At this time, you may notice the coolant
temperature gauge moves toward the red
zone and a message may appear in the
information display. You may notice a reduction in vehicle
speed caused by reduced engine power in
order to manage the engine coolant
temperature. Your vehicle may enter this
mode if certain high-temperature and
high-load conditions take place. The
amount of speed reduction depends on
vehicle loading, grade and ambient
temperature. If this occurs, there is no
need to pull off the road. You can continue
to drive your vehicle.
The air conditioning may automatically
turn on and off during severe operating
conditions to protect the engine from
overheating. When the coolant
temperature decreases to the normal
operating temperature, the air conditioning
turns on.
If the coolant temperature gauge moves
fully into the red zone, or if the coolant
temperature warning or service engine
soon messages appear in your information
display, do the following:
1. Pull off the road as soon as safely
possible and shift the transmission into
park (P).
2. Leave the engine running until the coolant temperature gauge needle
returns to the normal position. After
several minutes, if the temperature
does not drop, follow the remaining
steps.
3. Switch the engine off and wait for it to
cool. Check the coolant level.
4. If the coolant level is at or below the minimum mark, add prediluted coolant
immediately.
5. If the coolant level is normal, restart the engine and continue.
367
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

It is very important to use prediluted
coolant approved to the correct
specification to avoid plugging the small
passageways in the engine cooling system.
See Cooling System Capacity and
Specification (page 455). Do not mix
different colors or types of coolant in your
vehicle. Mixing of engine coolants or using
an incorrect coolant may harm the engine
or cooling system components and may
not be covered by the vehicle Warranty.
Note: Coolants marketed for all makes and
models may not be approved to our
specifications and may cause damage to
the cooling system. Resulting component
damage may not be covered by the vehicle
Warranty.
If the coolant level is at or below the
minimum mark, immediately add
prediluted coolant.
For vehicles with overflow coolant systems
with a non-pressurized cap on the coolant
recovery system, add coolant to the
coolant recovery reservoir when the engine
is cool. Add prediluted coolant to the
maximum level. For all vehicles which have
a coolant degas system with a pressurized
cap, or if it is necessary to remove the
coolant pressure relief cap on the radiator,
follow these steps to add engine coolant:
1. Turn the engine off and let it cool.
2. Slowly unscrew the cap. Any pressure escapes as you unscrew the cap.
3. Slowly fill the coolant reservoir with prediluted engine coolant to within the
minimum and maximum range on the
engine coolant reservoir. If you
removed the radiator cap in an
overflow system, fill the radiator until
the coolant is visible and the radiator
is almost full. If you add coolant to
bring the level within the minimum and
maximum range when the engine is not
cold, the system may remain under
filled. 4.
Replace the coolant reservoir cap. Turn
the cap clockwise until it contacts the
hard stop.
5. Check the coolant level in the coolant reservoir the next few times you drive
your vehicle. If necessary, add enough
prediluted engine coolant to bring the
coolant level to the proper level.
Note: If prediluted coolant is not available,
use the approved antifreeze concentrate
diluting it to 50/50 with distilled water. See
Cooling System Capacity and
Specification (page 455). Using water that
has not been deionized may contribute to
deposit formation, corrosion or plugging of
the small cooling system passageways.
If you have to add more than
1.1 qt (1 L) of
engine coolant per month, have your
vehicle checked as soon as possible.
Operating an engine with a low level of
coolant can result in engine overheating
and possible engine damage.
In case of emergency, you can add a large
amount of water without prediluted
coolant in order to reach a vehicle service
location. On arrival do the following:
1. Drain the cooling system.
2. Chemically clean the cooling system. We recommend Motorcraft Premium
Cooling System Flush.
3. Refill with prediluted coolant as soon as possible.
Water alone, without prediluted coolant,
can cause engine damage from corrosion,
overheating or freezing.
Do not use the following as a coolant
substitute:
• Alcohol.
• Methanol.
• Brine.
• Any coolant mixed with alcohol or
methanol antifreeze.
369
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

Alcohol and other liquids can cause engine
damage from overheating or freezing.
Do not add extra inhibitors or non-specified
additives to the coolant. These can be
harmful and compromise the corrosion
protection of the coolant.
Engine and Secondary Cooling
System Refill Procedure
Perform this procedure when refilling the
engine or secondary cooling systems after
it has been drained or become extremely
low:
1. Before you remove the cap, turn the
engine off and let it cool.
2. When the engine is cool, wrap a thick cloth around the cap. Slowly turn cap
counterclockwise until pressure begins
to release.
3. Step back when the pressure releases.
4. When you are sure that all the pressure
has been released, use the cloth to turn
the cap counterclockwise and then
remove it.
5. Slowly add prediluted engine coolant to the coolant reservoir until the
coolant level is within the minimum
and maximum range as listed on the
reservoir.
6. Reinstall the pressure relief cap.
7. Start and run the engine at 2000 rpm for 2 minutes.
8. Shut the engine off, and remove the pressure relief cap as previously
outlined.
9. If required, add prediluted engine coolant to the coolant reservoir until
the coolant level is within the minimum
and maximum range as listed on the
reservoir. 10.
Engine cooling system: Repeat steps
5 through 9 until the coolant level has
stabilized and is no longer dropping
after each step and the upper
radiator hose at the radiator is warm
to the touch, indicating that the
engine thermostat is open and
coolant is flowing through the
radiator.
11. Check the secondary cooling system.
Repeat steps 1 through 10 until the
coolant level has stabilized and is no
longer dropping after each step and
the lower passenger side of the
secondary radiator is warm to the
touch, indicating secondary
thermostat is open and coolant is
flowing through the entire system.
12. Check the coolant level in both systems before you drive your vehicle
the next few times.
13. If necessary, add prediluted engine coolant to the coolant reservoirs until
the coolant level is within the
minimum and maximum range as
listed on the reservoir. After you add
coolant, check the coolant
concentration.
Recycled Coolant
We do not recommend the use of recycled
coolant as an approved recycling process
is not yet available.
Dispose of used engine coolant in an
appropriate manner. Follow your
community ’s regulations and standards
for recycling and disposing of automotive
fluids.
370
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

Severe Climates
If you drive in extremely cold climates:
•
It may be necessary to increase the
coolant concentration above 50%.
• A coolant concentration of 60%
provides improved freeze point
protection. Coolant concentrations
above 60% decrease the overheat
protection characteristics of the
coolant and may cause engine
damage.
If you drive in extremely hot climates:
• You can decrease the coolant
concentration to 40%.
• Coolant concentrations below 40%
decrease the freeze and corrosion
protection characteristics of the
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.
Coolant Change
Follow the specific mileage intervals, as
listed in the scheduled maintenance
information, to change the coolant. The
information display may display a message
to change coolant at this time. Add
prediluted coolant approved to the correct
specification. See Capacities and
Specifications (page 441). Engine-driven Cooling Fan
Your vehicle may have an engine driven
cooling fan drive also called a fan clutch.
This fan drive changes the fan speed to
match the vehicle
’s changing cooling air
flow requirements. Fan speed, fan noise
level and fuel consumption all will increase
based on the driving conditions that
include trailer towing, hill climbing, heavy
loads, high speed and high ambient
temperature, individually or in combination.
The fan drive is designed to provide the
minimum fan speed and resulting
minimum fan noise and fuel consumption
required to meet the ever-changing vehicle
cooling air flow requirements. You can hear
the amount of fan noise increasing and
decreasing as the engine power
requirements and vehicle driving conditions
change as you drive. This is normal to the
operation of your vehicle. You may also
hear high levels of the fan when the engine
is first started and should normally
decrease after driving for a short time.
ENGINE COOLANT CHECK -
7.3L WARNING:
Do not remove the
coolant reservoir cap when the engine is
on or the cooling system is hot. Wait 10
minutes for the cooling system to cool
down. Cover the coolant reservoir cap
with a thick cloth to prevent the
possibility of scalding and slowly remove
the cap. Failure to follow this instruction
could result in personal injury. WARNING:
Do not put coolant in
the windshield washer reservoir. If
sprayed on the windshield, coolant could
make it difficult to see through the
windshield.
371
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance

For vehicles with overflow coolant systems
with a non-pressurized cap on the coolant
recovery system, add coolant to the
coolant recovery reservoir when the engine
is cool. Add prediluted coolant to the
maximum level. For all vehicles which have
a coolant degas system with a pressurized
cap, or if it is necessary to remove the
coolant pressure relief cap on the radiator,
follow these steps to add engine coolant:
1. Turn the engine off and let it cool.
2. Unscrew the cap slowly. Any pressure
escapes as you unscrew the cap.
3. Fill the coolant reservoir slowly with prediluted engine coolant to within the
minimum and maximum range on the
engine coolant reservoir. If you
removed the radiator cap in an
overflow system, fill the radiator until
the coolant is visible and the radiator
is almost full. If coolant is added to
bring the level within the minimum and
maximum range when the engine is not
cold, the system may remain
underfilled.
4. Replace the coolant reservoir cap. Turn
the cap clockwise until it contacts the
hard stop.
5. Check the coolant level in the coolant reservoir the next few times you drive
your vehicle. If necessary, add enough
prediluted engine coolant to bring the
coolant level to the proper level.
Note: If prediluted coolant is not available,
use the approved antifreeze concentrate
diluting it to 50/50 with distilled water. See
Cooling System Capacity and
Specification (page 455). Using water that
has not been deionized may contribute to
deposit formation, corrosion or plugging of
the small cooling system passageways. If you have to add more than 1.1 qt (1 L) of
engine coolant per month, have your
vehicle checked as soon as possible.
Operating an engine with a low level of
coolant can result in engine overheating
and possible engine damage.
Note: During normal vehicle operation, the
coolant may change color from orange to
pink or light red. As long as the coolant is
clear and uncontaminated, this color change
does not indicate the coolant has degraded
nor does it require the coolant to be drained,
the system to be flushed, or the coolant to
be replaced.
Note: In case of emergency, you can add a
large amount of water without coolant in
order to reach a vehicle service location.
Water alone, without coolant, can cause
engine damage from corrosion, overheating
or freezing. When you reach a service
location, you must have the cooling system
drained, flushed and refilled using the
correct specification prediluted coolant or
antifreeze concentrate. See
Cooling
System Capacity and Specification (page
455
).
Do not use the following as a coolant
substitute:
• Alcohol.
• Methanol.
• Brine.
• Any coolant mixed with alcohol or
methanol antifreeze.
Alcohol and other liquids can cause engine
damage from overheating or freezing.
Do not add extra inhibitors or additives to
the coolant. These can be harmful and
compromise the corrosion protection of
the coolant.
Recycled Coolant
We do not recommend the use of recycled
coolant as an approved recycling process
is not yet available.
373
Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Third-Printing- Maintenance