2021 FORD F650/750 check engine

Maintain coolant concentration within
48% to 50%, which equates to a freeze
point between -30°F (-34°C) and -34°F
(-37°C). Check the coolant concentration
using a refractometer. We do not
recommend the use of hydrometers or
coolant test strips for measuring coolant
concentration.
Adding Coolant
WARNING: Do not add engine
coolant when the engine is on or the
cooling system is hot. Failure to follow
this instruction could result in personal
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.
Note: Automotive fluids are not
interchangeable. Do not use coolant or
windshield washer fluid outside of its
specified function and vehicle location.
Note: Do not use stop leak pellets, cooling
system sealants, or non-specified additives
as they can cause damage to the engine
cooling or heating systems. Resulting
component damage may not be covered by
the vehicle Warranty. It is very important to use prediluted
coolant approved to the correct
specification in order to avoid plugging the
small passageways in the engine cooling
system. See
Capacities and
Specifications (page 288). 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, add prediluted coolant
immediately.
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.
227
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

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
Capacities and Specifications (page 288).
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
Capacities and
Specifications (page 288).
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.
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.
228
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

Coolant Change
Change the coolant at specific mileage
intervals as listed in the scheduled
maintenance information. 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 281).
Engine-driven Cooling Fan (Fan
Clutch)
Your vehicle comes with 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 will hear
the amount of fan noise increasing and
decreasing as the engine power
requirements and vehicle driving conditions
change as you drive. This is to be expected
as being normal to the operation of your
vehicle. High levels of fan noise might also
be heard when your engine is first started,
and should normally decrease after driving
for a short time.
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
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
229
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

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
shutting down to prevent engine damage.
In this situation:
1. Pull off the road as soon as safely possible and switch the engine off.
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 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:
230
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

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.
ENGINE COOLANT CHECK -
6.7L DIESEL WARNING: Do not remove the
coolant reservoir cap when 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. WARNING:
To reduce the risk of
personal injury, make sure the engine is
cool before unscrewing the coolant
pressure relief cap. The cooling system
is under pressure. Steam and hot liquid
can come out forcefully when you loosen
the cap slightly. WARNING:
Do not add coolant
further than the MAX mark.
When the engine is cold, check the
concentration and level of the coolant at
the intervals listed in the scheduled
maintenance information. See Scheduled
Maintenance
(page 319).
Note: Make sure that the coolant level is
between the
MIN and MAX marks on the
coolant reservoir.
Note: Coolant expands when it is hot. The
level may extend beyond the
MAX mark.
Maintain coolant concentration within
48% to 50%, which equates to a freeze
point between -30°F (-34°C) and -34°F
(-37°C). Coolant concentration should be
checked using a refractometer. We do not
recommend the use of hydrometers or
coolant test strips for measuring coolant
concentration.
Adding Coolant WARNING:
Do not add engine
coolant when the engine is hot. Failure
to follow this instruction could result in
personal injury. WARNING:
Do not remove the
coolant reservoir cap when 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.
Note: Automotive fluids are not
interchangeable. Do not use coolant or
windshield washer fluid outside of its
specified function and vehicle location.
231
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

Note:
Do not use stop leak pellets, cooling
system sealants, or non-specified additives
as they can cause damage to the engine
cooling or heating systems. Resulting
component damage may not be covered by
the vehicle Warranty.
It is very important to use prediluted
coolant approved to the correct
specification in order to avoid plugging the
small passageways in the engine cooling
system. See Capacities and
Specifications (page 288). 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 Ford
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, add prediluted coolant
immediately.
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 under
filled.
4. Replace the coolant reservoir cap, turn
it clockwise until you feel a strong
resistance.
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
Capacities and Specifications
(page 288).
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.
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.
232
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

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 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
The following procedure should be used
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 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 (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 (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 any
coolant has been added, check the
coolant concentration.
Recycled Coolant
We do not recommend the use of recycled
coolant as an approved recycling process
is not yet available.
233
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance

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.
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.
Checking Coolant Corrosion
Inhibitor Additive Strength
At specific mileage intervals as listed in the
scheduled maintenance information
chapter, the coolant corrosion inhibitor
additive should be checked. An information
message may display in the optional
information display at this time. The
purpose of checking is to verify the correct
engine coolant concentration (freeze point
protection) and corrosion inhibitor additive
level (strength) of the coolant for
maximum engine performance and
protection. Three products are available to confirm
the life and health of the coolant, one tool,
a test kit and a coolant inhibitor additive:
234
F650750 (TBC) , enUSA, Edition date: 202010, Second-Printing Maintenance