2020 CHEVROLET LOW CAB FORWARD engine

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
216 Driving and Operating
When Increasing Vehicle Speed
When the cruise control resume
switch is operated, the speed
increases while the switch is held.
After the speed is increased to the
desired vehicle speed, and the
switch is released, the speed is set
at the increased vehicle speed.
If you want to increase the speed
quickly, press the accelerator pedal
and accelerate to the desired
vehicle speed. Then, operate the
cruise control set switch.When Increasing Vehicle Speed
Slightly
If the cruise control resume switch is
operated and released immediately,
the set vehicle speed increases
1.6 km/h (1 MPH) per operation.
When Decreasing Vehicle Speed
When the cruise control set switch
is operated, the speed decreases
while the switch is held.
After the speed is decreased to the
desired vehicle speed, and the
switch is released, the speed is set
at the decreased vehicle speed.
If you want to decrease the speedquickly, press the brake pedal to
cancel cruise control and decelerate
to the desired vehicle speed. Then,
operate the cruise control set
switch.
When Decreasing Vehicle Speed
Slightly
If the cruise control set switch is
operated and released immediately,
the set vehicle speed decreases
1.6 km/h (1 MPH) per operation.
When Canceling Cruise Control

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 217
Press the cruise control main switch
again to turn the cruise control
system off. The cruise control main
indicator light will go out.
The cruise control set speed is
canceled in the following cases:
.When the brake pedal is
pressed.
. When the selector lever is
shifted to the N position.
. When cruising speed is
approximately 27 km/h (17
MPH). *
. When the vehicle speed
decreases more than 20% below
your set speed.
. When the cruise control main
switch is turned off. *
. When the engine control switch
is turned to the LOCK position. *
. When trouble develops in the
system. *
Memory speed is eliminated. *
When you do not use the cruise
control, be sure to place the cruise
control main switch into off. When you place the engine control
switch into ACC, place the cruise
control main switch into off, then
reset the cruise control if you want
to use the cruise control again.
Using Cruise Control on Hills
How well your cruise control will
work on hills depends upon your
speed, load and the steepness of
the hills. When going up steep hills,
you may want to step on the
accelerator pedal to maintain your
speed. When going downhill, you
may have to brake or shift to a lower
gear to keep your speed down. Of
course, applying the brake takes
you out of cruise control. Many
drivers find this to be too much
trouble and do not use cruise
control on steep hills.
When Returning to Cruise Control
Driving
If you have canceled cruise control
under the following conditions, you
can return to the cruise control
driving condition before cancellation
when you operate and release the
cruise control resume switch. The
moment the resume switch is
released, the cruise set indicator
light comes on.
.
When pressing the brake pedal.
. When the selector lever is
shifted to the N position.
When the vehicle speed decreases
to 40 km/h (25 MPH) or less, it is
not possible to return to the cruise
control driving. You must reset the
cruise control.
If the cruise control is turned back
on while the vehicle speed exceeds
what is set prior to the cancellation
of cruise control, the set vehicle
speed cannot be changed until the
vehicle reaches to the set speed.
Also, the vehicle speed must be 1
MPH below the previously set
vehicle speed.
If you hold the switch at the +RES
position, the vehicle will keep going
faster until you release the switch or
apply the brake. So unless you want
to go faster, do not hold the switch
at the +RES position.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
218 Driving and Operating
Exhaust Brake Function
Diesel Vehicles Equipped with
Exhaust Brake-interlocked Cruise
Automatic activation of the exhaust
brake during cruise control driving
suppresses an increase in the
speed on a downhill slope,
decreasing the need for the driver to
apply the regular brake pedal. The
exhaust brake does not activate
when the exhaust brake switch is
turn off.
The maximum slope angle at which
the system can control the vehicle
speed increase is different
depending on the load the vehicle is
carrying.
Automatic Activation and
Automatic Release of Exhaust
Brake
The exhaust brake is engaged when
the vehicle speed exceeds the set
speed on a downhill slope.
The exhaust brake is disengaged
when the vehicle slows down close
to the set.
Fuel
Fuel for Diesel Engines
Diesel Fuel Requirement and
Fuel System
Fuel Requirements
Use of fuels other than ultra
low-sulfur fuel may not conform to
emission regulations.
The fuel supply pump, injector or
other parts of the fuel system and
engine can be damaged if you use
any fuel or fuel additive other than
those specifically recommended by
the dealer.
To help avoid fuel system or engine
damage, pay attention to the
following:
.Some service stations mix used
engine oil with diesel fuel. Some
manufacturers of large diesel
engines allow this; however, for
your diesel engine, do not use
diesel fuel which has been
contaminated with engine oil.
Besides causing engine damage, such fuel can also
affect emission control. Before
using any diesel fuel, check with
the service station operator to
see if the fuel has been mixed
with engine oil.
. Take care not to run out of diesel
fuel. If you do run out of fuel,
you may need to bleed air out of
the supply pump to re-start the
engine after fuel has been filled.
Your vehicle is designed to use
either Number 1-D or Number 2-D
diesel fuel. However, for better fuel
economy, use Number 2-D diesel
fuel whenever possible. At
temperatures below -7 °C (20 °F),
Number 2-D fuel may pose
operating problems (see "Cold
Weather Operation" which follows).
At colder temperatures, use Number
1-D fuel (if available) or use a
"winterized" Number 2-D (a blend of
Number 1-D and Number 2-D). This
blended fuel is usually called
Number 2-D also, but can be used
in colder temperatures than Number
2-D fuel which has not been

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 219
"winterized". Check with the service
station operator to be sure you get
the properly blended fuel.
Do not use fuels other than those
recommended in this manual. Doing
so may adversely affect the engine.DIESEL FUEL/APPLICABLE
STANDARD (Sulfur content below 15ppm)
ASTM
(AMERICAN
SOCIETY FOR
TESTING and
MATERIALS) Based on D975
Number 1–D
S15 or Number
2-D S15 (below
15 ppm)
Biodiesel
Biodiesel, may also be referred to
as FAME blended (Fatty-acid methyl
ester) fuel is a renewable fuel
produced from vegetable oils or
animal fats that have been
chemically modified to make it
compatible with diesel fuel.
Caution
Do not use home-made biodiesel
or home test kits because the
quality cannot be verified by
approved scientific methods. Do
not use raw vegetable oil or other
unmodified bio-oils, fats,
or blends of vegetable oil with
diesel. They could damage the
fuel system and engine, and
damages would not be covered
by the vehicle warranty.
Caution
Do not use blends containing
more than 20% biodiesel. Any
engine, fuel system, or exhaust
after-treatment system damage
would not be covered by the
vehicle warranty.
As a renewable fuel, biodiesel
provides some environmental
benefits. However, biodiesel has
unique properties and needs to be handled differently than diesel fuel.
Its use presents additional risks and
may not be appropriate in all
situations. Certain vehicle operating
modes increase these risks and
should be avoided. Read further to
determine if your driving habits are
compatible with the use of biodiesel.
Biodiesel fuel quality degrades with
time and exposure to high
temperature quicker than Ultra Low
Sulfur Diesel fuel. More frequent
refueling provides the best
opportunity to have a supply of fresh
fuel. Storage at hot ambient
temperatures will accelerate
biodiesel degradation.
Owners who use very little fuel,
or who have vehicles or fuel stored
for extended periods of time, should
avoid the use of biodiesel blended
fuels above 5% by volume. When
vehicles are stored for longer than
one month, they should be run out
of biodiesel to below one-quarter
tank, refueled with Ultra Low Sulfur
Diesel fuel, and driven several miles
before storage.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
220 Driving and Operating
At temperatures below 0 °C (32 °F),
it is recommended to switch to Ultra
Low Sulfur Diesel fuel with no
biodiesel content, or to blends with
biodiesel containing less than 5% by
volume. At these extreme cold
temperatures, biodiesel blends
higher than 5% by volume may
cause fuel filter plugging and
system gelling, which can lead to
vehicle operability problems.
Fuels improperly blended for cold
temperature operation may result in
restricted fuel filters and degraded
vehicle performance. The vehicle is
equipped with a fuel heating system
to provide a level of protection
against filter plugging from gelling or
waxing of conventional diesel fuel
and biodiesel blends. If the
operating temperature is far below
the temperature at which gelling or
waxing of the fuel occurs, the
system will not prevent all cases of
filter plugging.
If the vehicle experiences a fuel
filter restriction, the on-board
monitoring system will alert the
driver that the fuel filter requiresservice. The fuel filter, however, will
not prevent all damage caused by
poor quality biodiesel.
Biodiesel Blends
Use biodiesel blends that meet the
ASTM specification D6751.
Retail pumps dispensing blends
containing up to 5% biodiesel (B5)
are not required to be labeled with
the concentration of biodiesel.
Blends up to B5 must meet ASTM
D975 (Grades No. 2-D or No. 1-D
S15 Ultra Low Sulfur Diesel). When
refueling with a biodiesel blend
above B5, one of the following
labels should appear on the
dispenser:
Caution
Do not use blends containing
more than 20% biodiesel. Any
engine, fuel system, or exhaust
after-treatment system damage
would not be covered by the
vehicle warranty.
Blends containing more than 5%
and up to 20% biodiesel must meet
ASTM specification D7467
(Biodiesel blend, B6 - B20) and are
labeled with an orange or blue label.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 221
To reduce the risk of poor quality
fuel, purchase biodiesel blends from
a fuel supplier or fueling station
which sells BQ-9000 certified
biodiesel. See www.bq-9000.org for
a list of certified marketers.
Biodiesel Blends in Canada
Biodiesel blends that meet the CAN/
CGSB-3.522 specifications up to
20% (B20) can be used. Do not use
biodiesel blends above 20%, as
they may damage the engine and
fuel system.
Cold Weather Operation
Diesel fuel is sensitive to
temperature. All diesel fuel has a
certain amount of paraffin
components, which are high in
energy value and help improve fuel
economy. But, when temperatures
are below -7 °C (20 °F), the paraffin
components begin turning into wax
flakes. If temperatures are low
enough, these flakes can obstruct
the fuel filters and stop fuel from
reaching the engine.At low temperatures, wax flakes are
more likely to form in Number 2-D
fuel than in Number 1-D (or
"winterized" Number 2-D) fuel. For
best operation at temperatures
below -7 °C (20 °F), use Number
1-D, or Number 2-D which has been
blended with Number 1-D for winter
use. When temperatures are
consistently below (or near) -18 °C
(0 °F), use Number 1-D if at all
possible. Bear in mind, however,
that even Number 1-D fuel will form
wax flakes when temperatures are
extremely low.
Do not use home heating oil or
gasoline in your diesel engine;
either may cause engine damage.
The addition of kerosene will not
unplug a filter plugged with wax.
Warming a "waxed" filter to a
temperature of 0 °C to 10 °C (32 °F
to 50 °F) will return the wax to
solution. Filter replacement is not
normally required.
Water in Fuel
During refueling, it is possible for
water (and other contaminants) to
be pumped into your fuel tank along
with the diesel fuel. This can occur if
a service station does not regularly
inspect and clean its fuel tanks, or if
a service station receives
contaminated fuel from its
supplier(s).
To protect your engine from
contaminated fuel, there is a water
separator system on the engine
which allows you to drain excess
water from the fuel.
{Warning
The drained water/diesel fuel
mixture is flammable, and could
be hot. To help avoid personal
injury or death and/or property
damage, do not touch the fuel
coming from the water separator
drain valve, and do not expose
the fuel to open flames or sparks.
(Continued)

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
222 Driving and Operating
Warning (Continued)
Be sure you do not overfill the
drain pan. Heat (such as from the
engine) can cause the fuel to
expand. If the container is too full,
fuel could be forced out of the
pan. This could lead to a fire and
the risk of personal injury and/or
vehicle damage.
Biocides
In warm or humid weather, fungus,
and/or bacteria may form in diesel
fuel if there is water in the fuel.
Fungus or bacteria can cause fuel
system damage by plugging the fuel
lines, fuel filters or injector. They
can also cause fuel system
corrosion.
If fungus or bacteria has caused fuel
system problems, you should have
your authorized dealer correct these
problems. Then, use a diesel fuel
biocide to sterilize the fuel system
(follow the biocide manufacturer's
instructions). Biocides are available from your dealer, service stations,
parts stores and other automotive
places. See your authorized dealer
for advice on using biocides in your
area and for recommendations on
which biocides you should use.
Smoke Suppressants
Because of extensive testing of
treated fuel versus untreated fuel,
the use of a smoke suppressant
additive is not recommended
because of the greater possibility of
stuck rings and guttered valves,
resulting from excessive ash
deposits.
Water Separator
The purpose of the water separator
is to separate any water from the
fuel that may have formed in the
fuel tank due to condensation.
The water separator is located on
the bottom of the fuel filter.
Caution
Remaining water that is not
discharged from the water
separator could freeze and
damage the vehicle.
If the warning light comes on
while the engine is in operation,
promptly drain the water from the
water separator (fuel filter).
Continuing to drive with the light
remaining on could damage the
fuel injection system. If this
happens, have the vehicle
checked and serviced by the
nearest dealer.
Draining Water from the Fuel
Filter
Clean off any fuel that has adhered
to the vehicle body.
Starting the engine immediately
after draining the water from the fuel
filter requires a little more time than
usual. If the engine does not start in
10 seconds, wait for a while and try
again.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 223
Fuel will be mixed in the drained
water. Dispose of it in a method
conforming to the regulatory
requirements in your state.
If the water separator (fuel filter)
requires frequent draining, have the
fuel system inspected at your
dealer.
Pre Fuel Filter (Chassis-side)1. Attach a plastic hose to the drain plug (2) on the bottom of
the chassis-side fuel filter and
put the other end of the hose in
a container placed beneath the
filter. 2. Loosen the drain plug and
move the priming pump (1) up
and down by hand between
10 and 20 times.
3. Fully tighten the drain plug (2) and move the priming pump (1)
several times.
Fuel Filter (Engine-side)1. Attach a plastic hose to the drain plug (2) on the bottom of
the engine-side fuel filter (1)
and put the other end of the
hose in a container placed
beneath the filter.
2. Loosen the drain plug andmove the priming pump up and
down by hand between 10 and
20 times.
3. Fully tighten the drain plug and move the priming pump several
times.
4. Test run the engine and check that there are no fuel leaks
from the drain plug of the
engine-side fuel filter. Also
check that the water separator
(fuel filter) warning light
stays off.