check engine light FORD SUPER DUTY 2021 Owner's Manual

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 565).
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). 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
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, add prediluted coolant
immediately.
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Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-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.
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Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Maintenance

Check Every Month
Air filter restriction gauge. 1
Engine oil level.
Function of all interior and exterior lights.
Tires including the spare for wear and proper pressure. Windshield washer fluid level.
Fuel and water separator. Drain if necessary or if indicated by the information display. 1
Holes and slots in the tail pipe to make sure they are functional and clear of debris. 1
1 Diesel vehicles only. Check Every Six Months
Battery connections. Clean if necessary.
Body and door drain holes for obstructions. Clean if necessary. Cooling system fluid level and coolant strength.
Door weatherstrips for wear. Lubricate if necessary.
Hinges, latches and outside locks for proper operation. Lubricate if necessary. Parking brake for proper operation.
Safety belts and seat latches for wear and function.
Safety warning lamps, brake, ABS, airbag and safety belt for operation.
Washer spray and wiper operation. Clean or replace blades as necessary.
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Super Duty (TFE) Canada/United States of America, enUSA, Edition date: 202008, Second-Printing Scheduled Maintenance