2008 FORD F750 engine

Running out of fuel
Avoid running out of fuel as this will allow air to enter the fuel system,
which will make restarting the vehicle difficult.
If you have run out of fuel:
•If your vehicle is equipped with dual fuel tanks,add at least 4–5
gallons (15–19 liters) of fuel to each tank before attempting to restart
the engine.
•The fuel system must be primed before attempting to restart the
engine. Refer to the engine operator’s manual for instructions on
priming the engine.
•Use caution not to overheat and damage the starterby cranking
the engine for an excessive period of time. You may need to crank the
engine for a longer time than normal. If the engine fails to start in 30
seconds, turn the ignition to the OFF position and wait for two
minutes before cranking the engine again.
•Any remaining trapped air will self-purge from the fuel system once
the engine starts running.
•The engine may run rough and produce white smoke while air is in
the fuel system. This is normal and should stop after a short period of
time.
FUEL CONSUMPTION IMPROVEMENT MEASURES
There are two important factors you can control to improve fuel
economy: the mechanical condition of your vehicle and how you drive it.
A properly maintained vehicle will deliver better performance than a
neglected vehicle. Always follow your maintenance schedule to keep your
vehicle in top operating condition.
Also, your driving habits have a significant influence on use of fuel. By
following these suggestions, you can stretch your fuel use:
•Avoid changes in speed as much as possible.
•Anticipate changing traffic conditions. Sudden stops and fast
acceleration waste fuel.
•Avoid extensive idling.
•Do not drive with your foot resting on the brake pedal.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
178

Essentials of good fuel economy
Measuring techniques
Your best source of information about actual fuel economy is you, the
driver. You must gather information as accurately and consistently as
possible. Fuel expense, frequency of fill-ups or fuel gauge readings are
NOT accurate as a measure of fuel economy. We do not recommend
taking fuel economy measurements during the first 1,000 miles
(1,600 km) of driving (engine break-in period). You will get a more
accurate measurement after 2,000–3,000 miles (3,000–5,000 km).
The advertised fuel capacity of the fuel tank(s) on your vehicle is equal
to the rated refill capacity of the fuel tank(s) as listed inFuel tanksin
this chapter. The advertised capacity is the amount of the Indicated
Capacity and the Empty Reserve combined. Indicated Capacity is the
difference in the amount of fuel in a full tank and a tank when the fuel
gauge indicates empty. Empty Reserve is the small amount of usable fuel
remaining in the fuel tank after the fuel gauge indicates empty.
The amount of Empty Reserve varies and should not be relied
upon to increase driving range. When refueling your vehicle after
the fuel gauge indicates empty, you might not be able to refuel
the full amount of the advertised capacity of the fuel tank due to
the empty reserve still present in the tank.
Filling the tank
For consistent results:
•Use the same fill rate setting (low - medium - high) each time during
filling.
•Allow three automatic click-offs when filling.
•Always use fuel of a known quality, preferably a national brand.
•Have the vehicle loading and distribution the same every time.
•When refueling a vehicle equipped with dual fuel tanks, if the two
tanks are not filled equally, the fuel gauge reading may fluctuate
slightly until the fuel level between the two tanks balance out and
become equal.
Your results will be most accurate if your filling method is consistent.
Note:For vehicles equipped with dual fuel tanks, engine performance
may degrade if fuel is not added to both tanks when refueling.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
179

Conditions
•Carrying unnecessary weight may reduce fuel economy.
•Fuel economy may decrease with lower temperatures during the first
8–10 miles (12–16 km) of driving.
•Flat terrain driving improves fuel economy over hilly roads.
•Transmissions give their best fuel economy when operated in the top
cruise gear and with steady pressure on the accelerator.
•Close windows for highway driving.
DIESEL PARTICULATE FILTER (DPF)
Your vehicle is equipped with a diesel particulate filter (DPF), as part of
the after-treatment exhaust system, to trap soot and other large particles
produced by the engine combustion process. The soot that accumulates
in the filter must be periodically reduced to ash to prevent excessive
exhaust restriction. The soot reduction process, also known as “filter
regeneration,” is generally performed automatically by your engine and
after-treatment system.
The normal operating temperature of the exhaust system is very
high. Never work around, or attempt to repair, any part of the
exhaust system until it has cooled. Use special care when working
around the diesel particulate filter. The DPF heats up to a high
temperature after only a short period of engine operation, and can
remain hot even after the engine is turned off. Failure to follow these
instructions may result in personal injury.
Diesel particulate filter regeneration (Caterpillar engine only)
DPF regeneration requires no operator interaction and may occur at any
time. A small increase in engine sound-level during filter regeneration is
normal and should be no reason for concern.
A separate fuel injector/nozzle, which requires periodic cleaning, is used
in the regeneration process. Refer to Caterpillar’sOperation and
Maintenance Manualfor details regarding cleaning requirements.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
181

Diesel particulate filter regeneration (Cummins engine only)
Under most operating conditions, DPF regeneration will be transparent
to the operator. A small increase in engine/turbo sound-level is normal
during filter regeneration. If, however, your engine is operated for
extended periods of time under one of the following conditions, operator
assistance may be required to facilitate the filter regeneration process:
•Vehicle is operated in stop-and-go traffic and/or maintains low speeds
as in a city/delivery driving
•Engine is started and shut-off frequently
•Vehicle payload is relatively light
•Vehicle is regularly operated in cold ambient temperatures (i.e. below
0°F [-18°C])
Diesel Particulate Filter Four–Level Loading Chart
Level/Lamp status Filter status Requested action
Level 1
DPF lamp solidRegeneration required. Drive on highway at
highway speedsOR
started “parked
regeneration” to
prevent loss of engine
performance. Level 2
DPF lamp flashingNearly full. Engine
performance is limited.
Level 3
DPF lamp flashing +
Service Engine Soon
lamp solidFull. Engine is
increasingly limited.Perform “parked
regeneration” to
prevent loss of engine
performance.
Level 4
Stop Engine lamp
solidOver full. Engine
performance is highly
limited. Continued
operation may result
in irreparable damage
to the filter.Pull vehicle safely off
roadway, turn on
hazard flashers and
shut down engine as
soon as possible. Seek
service immediately.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
182

Instrument cluster lamp(s) will
illuminate and/or flash when
operator assistance is required. In
addition, engine performance will
become increasingly limited above
Level 1.
At Levels 1 and 2, two courses of action may be taken by the operator to
facilitate filter regeneration:
1. The vehicle may be driven on the highway at highway speeds,
2. The operator may perform a parked regeneration by following the
steps inParked regeneration procedure (Cummins engine only).
At Level 3, performing a parked regeneration is the only available course
of action (short of professional servicing) available to the operator for
regenerating the filter. At Level 4, professional servicing is the only way
to regenerate the filter.
Parked regeneration procedure (Cummins engine only)
When performing the parked regeneration procedure, make
certain the vehicle is safely off roadway, and the exhaust system
is away from people, or any flammable materials, vapors, or structures.
Engine speed may increase during parked regeneration.
Note:Parked regeneration is only available when the DPF lamp on the
instrument cluster is illuminated (solid or flashing).
1. Bring the vehicle to a complete stop on level ground and safely off the
road with the exhaust system away from people, flammable materials,
vapors or structures.
2. If your vehicle is equipped with an automatic transmission and a
steering column shift lever, place transmission in P (Park). Otherwise,
place the transmission in N (Neutral).
3. Remove feet from the accelerator pedal and clutch pedal (if
equipped).
4. Set the parking brake.
5.Within 5 seconds of setting the parking brake,remove foot from
the service brake pedal.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
183

When these steps are performed successfully in the order outlined above,
the DPF lamp will begin flashing at a rate of once every 10 seconds. The
engine speed may also increase slightly. To allow parked regeneration to
continue uninterrupted:
1. The vehicle must remain parked
2. The transmission must remain in P (Park) or N (Neutral) (as
previously described in Step 2).
3. The accelerator pedal, service brake pedal, and clutch pedal (if
equipped) must not be depressed
4. The parking brake must remain set
On average (depending on filter level and other factors), the process will
take 20–30 minutes to complete. The DPF lamp will turn off when the
process is complete. Repeat Steps 1–5, if parked regeneration is
interrupted.
To discontinue parked regeneration (Cummins engine only)
Depress any of the floor pedals to discontinue parked regeneration.
Diesel particulate filter maintenance and service
The DPF is designed to retain a relatively large amount of residual ash
and provide many miles and hours of maintenance-free operation. At
some point, generally beyond 150,000 miles (240,000 km) or 5,000 hours
of operation (whichever comes first), the DPF will require professional
cleaning to remove the accumulated ash
The exact number of miles or hours of operation will vary greatly
depending upon vehicle/engine loading and operating conditions, ash
content of the engine oil, and quality of the diesel fuel used in your
truck. Adhering to your engine manufacturer’s recommended oil and fuel
specifications will maximize the miles and hours of operation before a
DPF professional cleaning is required. Refer to your engine
manufacturer’s owner’s manual for more details regarding recommended
maintenance and service of your DPF.
Exhaust outlet assembly
The normal operating temperature of the exhaust system is very
high. Never work around or attempt to repair any part of the
exhaust system until it has cooled. Failure to follow these instructions
may result in personal injury.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
184

The exhaust outlet assembly on your vehicle is a uniquely functioning
device that accompanies the DPF assembly. It is designed to help control
the temperature of the exhaust during the DPF regeneration process.Do
not modify or remove this device. Modification of the system
and/or additions of aftermarket devices can reduce the
effectiveness of the system, as well as cause damage to the
exhaust system and/or engine. Any modifications may also
invalidate the vehicle and/or engine warranties. See the vehicle
and engine warranty guides for more information.
The inlet holes in the side of the assembly are functional. These holes
allow outside air to be drawn into the outlet assembly. The holes need to
be kept clear of mud and other foreign material to maintain proper
functionality of the system. One way to keep the holes clear is to spray
the outlet assembly with a hose when washing the vehicle. Failure to
keep the functional holes clear of foreign material may result in the holes
becoming blocked or plugged.Blocked/plugged holes or
modification/removal of the outlet assembly could result in
elevated exhaust temperatures which may result in
vehicle/property damage and/or personal injury.
NOISE EMISSIONS – EXTERIOR
In order to comply with the federal exterior noise regulations, your
vehicle may be equipped with noise emission items. Depending on the
vehicle configuration, it may have all or some of the following items:
Air Intake System
•Air Cleaner:should be inspected and its location should not be
altered. Do not alter inlet and outlet piping.
Body
•Wheel Well:splash shields, cab shields and under-hood insulation
should be inspected for deterioration, dislocation, and orientation.
Cooling System
•Check the fan for damage to blades; replace, if damaged, with the
recommended parts. Inspect for fan to shroud interference, and any
damage to shroud such as cracks and holes.
•The fan ratio should not be changed and the fan spacer dimensions
and positions should not be altered.
•Inspect the fan clutch for proper operation, make sure that the fan is
disengaged when cooling of the engine is not required.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
185

•Check for proper operation of radiator shutters, if equipped. The
shutters should be open during normal operating temperatures.
Engine and Driveline System
•Transmission Enclosure:inspect for cracks, holes, and tears. Clean
any deposits such as oil, dirt, and stones.
•Engine valve covers and block covers are made to damp out engine
mechanical noise and, if needed, should be replaced with
recommended parts. Check for mechanical isolations.
Exhaust System
•Inspect the exhaust system for leaks at various joint connections and
tighten the clamps.
•Do a visual inspection for cracks or holes in the muffler and tail pipe.
•Always use the recommended parts when items need to be replaced.
•The tail pipe elbow or offset tail pipe orientation must not be changed
from the standard position as originally received.
•To avoid abnormal changes in vehicle sound levels, it is necessary for
the owner to perform inspections and necessary maintenance at the
intervals shown in theScheduled Maintenance Guidechapter.
POWER STEERING FLUID
Check the power steering fluid level using the following procedure. If
adding fluid is necessary, refer toLubricant Specificationsin this
chapter for the proper fluid type. Refer to theScheduled Maintenance
Guidechapter for the recommended service intervals.
1. Set the parking brake, shift into N (Neutral) (automatic transmission)
or 1 (First) (manual transmission) and turn the engine off.
2. Open the hood.
3. Clean the top of the power steering fluid reservoir.
4. Remove the dipstick from the reservoir and wipe the dipstick clean.
5. Reinstall the dipstick. Remove it again and check the fluid level.
2008 F-650/750(f67)
Supplement
USA(fus)
Maintenance and Specifications
186