
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
Vehicle Care 249
Engine Overheating
When the Engine Overheats
The engine cooling system may
overheat if the engine coolant level
is too low, if there is a sudden loss
of engine coolant (such as radiator
hose failure), or if other problems
occur. It may also temporarily
overheat during severe operating
conditions such as:
.Climbing a long hill on a hot day.
. Stopping after high-speed
driving.
. Idling for long periods in traffic.
If engine power drops and the
needle on the engine coolant
temperature gauge goes up above
the upper limit of the safety zone
and enters the "H" zone, the engine
is overheating. The engine overheat
warning light will come on and the
warning buzzer will sound. Either
steam or boiling engine coolant will
squirt out of the radiator. The
vehicle will also have an “OVERHEAT”
message displayed. Take the
following corrective actions
immediately.{Warning
To help avoid being burned:
Do not tilt the cab or open the
engine access cover if you see or
hear steam or engine coolant
escaping from the engine
compartment. Wait until no steam
or engine coolant can be seen or
heard before tilting the cab or
opening the engine cover.
Do not remove the radiator cap or
engine coolant reserve tank cap if
the engine coolant in the tank is
boiling. Also do not remove the
radiator cap while the engine and
radiator are still hot. Scalding fluid
and steam can be blown out
under pressure if either cap is
taken off too soon.
You and others could be seriously
injured. If Steam Is Coming from the
Engine Compartment
{Warning
If the engine coolant temperature
gauge shows an overheat
condition or you have other
reasons to suspect the engine
may be overheating, continued
operation of the engine (other
than as described here) even for
a short period of time may cause
a fire and the result in personal
injury and severe vehicle
damage. Take immediate action
as outlined.
You and others could be seriously
injured.
If you see or hear escaping steam
or have any other reason to suspect
there is a serious overheat
condition, stop and park the vehicle
as soon as it is safe to do so, turn
on the hazard warning flasher and
then turn off the engine immediately
and safely exit the vehicle.

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
Vehicle Care 251
4. If no steam or engine coolantcan be seen or heard from the
engine compartment:
.Tilt the cab or open the
engine access cover.
‐If the engine coolant is
boiling, wait until it stops
before proceeding.
‐ Look at the see-through
reserve tank. The
engine coolant level
should be between the
"MAX" and "MIN" lines
on the reserve tank.
‐ If necessary, pour
engine coolant (See
Engine Coolant 0243
for the proper coolant
and water mixture) into
the reserve tank only,
not directly into the
radiator. Also, do not
check engine coolant
level at the radiator.
. Make sure the fan belts are
not broken, or off the
pulleys, and that the fan
turns when the engine is started. Make sure the fan
blade and pulleys are not
broken.
. Check the radiator hoses
and connections, heater
hoses and connections,
radiator, water pump, EGR
cooler, and SCR system
and hoses for leakage.
If you do not find a leak or
other problem, carefully add
engine coolant to the
reserve tank.
If the engine coolant level in
the reserve tank is at the
correct level but there is still
an indication on the
instrument panel of an
overheat condition:
You must let the engine
cool first. You may then add
engine coolant directly to
the radiator. See “Adding
Engine Coolant” under
Engine Coolant 0243.
5. Inspect to see if there is any dirt, etc. attached to the front
surface of the radiator. Also, inspect to see if there is
anything blocking the core.
If there is anything attached,
clean and remove it.
6. After the inspection, regardless of the vehicle condition, please
contact the nearest dealer.
Once the engine coolant
temperature gauge no longer
signals an overheat condition, you
can resume driving at a reduced
speed. Return to normal driving
after about 10 minutes if the gauge
pointer does not again show an
overheat condition.
When tap water only has been used
for engine coolant in an emergency,
change the engine coolant as soon
as possible.
Engine damage may be caused if
an overheating engine is suddenly
refilled with water. Instead, refill
slowly.

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
Vehicle Care 255
Another characteristic of the HBB
system is that the brake pedal may
be pressed easily to the floor with
the vehicle at a stop. This is not a
sign of malfunction.
When the engine is running, the
system automatically charges the
accumulator whenever pressure has
been reduced after braking. Auto
charge may be activated without
braking, depending on temperature
changes in the accumulator. During
auto charge, a hissing and clicking
sound can be heard. This is not a
malfunction.
With the engine running, a booming
sound can be heard during hard
braking. This comes from the
brake-fluid pump. It is not a
malfunction.
Applying continuous hard braking
for a long time will lead to
considerable temperature rise in the
HBB pump. Such overworking of the
brakes is best avoided.Vacuum or hydraulic power
assisted brakes
If the engine stops, do not pump the
brakes. The system is designed to
stop the vehicle with reserve power
assist if the brake pedal is held
down. This reserve is greatly
reduced each time you apply and
release the brakes. If, when you
turn the steering wheel during
braking, the vehicle does not turn,
release some pressure from the
brake pedal.
In a Vehicle Equipped with an
HBB, Do Not Keep the Brake
Pedal Pressed for an Extended
Period
Caution
Failure to follow the above
instruction will cause the oil inside
the HBB oil pump to get very hot.
This could damage the HBB tank
and deteriorate seals and also
could cause damage to the HBB
oil pump, HBB unit and/or HBB
(Continued)
Caution (Continued)
hosing. Eventual leakage of HBB
oil, sudden increase in brake
pedal resistance and fire could
unexpectedly result in a crash.
Hydraulic Brake Booster (HBB)
Fluid (5500HD/5500XD Series)
The HBB system has been
designed to use Dexron VI ATF
fluid. If any other fluid is used with
this system, rubber components
may be damaged, oil may leak and
the system may malfunction. It is
important to remember that the fluid
used in the hydro-booster is
completely different in
characteristics from the brake fluid
used in the master and wheel
cylinders.
If hydro-booster fluid and brake fluid
from the master cylinder are
mistakenly mixed together and
used, rubber components will
deteriorate as a result of insufficient
lubrication. Any resultant oil leakage
or system malfunction can in turn

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
Vehicle Care 261
Rear Axle (Gear Oil Viscosity Chart)
Gear Oil Viscosity Chart
Select appropriate gear oil in accordance with the table below. It is important
to select the viscosity appropriate for the temperature at which your vehicle
operates. Use the following table for making correct selections.

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
Vehicle Care 309
this precaution can lead to heat
deformation and breakage of plastic
components, or to water leaks into
the cab. When using an automatic
car or truck-wash, ensure that a
distance of at least 0.4 m
(15.75 inches) is maintained
between the nozzle and the vehicle,
and when washing door windows,
that the spray is perpendicular to
the surface of the glass.
Ensure that all detergent is fully
washed and wiped away.
Particularly in the case of strong
alkaline detergents (typically those
for industrial uses), there is a
danger that hairline cracks can
develop in lighting-cluster lenses if
the vehicle is operated without
detergent being fully wiped away.
Always read the detergent
manufacturer's instructions carefully
before use. Airborne dirt that
adheres to plastic front bumpers as
a result of rain, for example, can be
difficult to remove. In such a case,
use a commercially-available
cleaner to clean away the dirt, and
then apply a wax for use with plastic
components.Vehicle Storage
In order to maintain your vehicle's
attractive appearance as long as
possible, special consideration must
be given to its storage location.
If the vehicle is stored or kept for an
extended period of time in any of
the following locations, a chemical
change may occur in the paint work,
resulting in staining, discoloration,
rusting, and corrosion of
components.
.Locations where a large amount
of oily matter, soot, heavy smoke
or metal powder can adhere to
the vehicle.
. Areas around pharmaceutical
plants and other facilities that
discharge chemical matter.
. Coastal areas
. Locations where a large amount
of dead bugs, bird droppings or
tree sap can adhere to the
vehicle.
Polishing and Waxing
Periodic polishing and waxing is
recommended to remove built-up
residue and eliminate any
"weathered" appearance.
Your authorized dealer offers
several polishes and cleaners which
have proven value in maintaining
original finish appearance and
durability.
Painted and chrome-plated surfaces
should be waxed once or twice a
month, or whenever water is being
poorly repelled on the surfaces.
Ensure that wax is not applied in
direct sunlight, and that the
temperature of the painted surface
is no more than 40 °C (104 °F).
Always follow the instructions
provided with your wax product.
Do not use wax containing abrasive
material. Failure to observe this
precaution can lead to scratching of
painted surfaces or plastic
components.

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
Service and Maintenance 319
.Frequent short trips of less than
16 kilometers (10 miles) in sub-
freezing temperatures
. Frequent and extended low-
speed engine operation (door-
to- door deliveries, stop- and- go
traffic, etc.)
. Driving on unpaved roads with
heavy dust
. Towing a trailer
Power Take Off (PTO) and
Extended Idle Use
When the vehicle is used with the
PTO equipment or used in a way
that requires extended idle time,
one hour of use shall be deemed
the same as 33 miles. See Driver
Information Center (DIC) 070 for
hourmeter.
Preventive Maintenance
As any mechanical device operates,
a certain amount of wear occurs.
The amount of wear depends on
certain variables –type and method
of operation and the schedule of
maintenance. These variables may be emphasized as critical to
malfunction but each is dependent
upon the other. For example, if a
vehicle is repeatedly overloaded,
driven at excessive speed or
improperly shifted, no schedule of
maintenance can prevent
malfunction. Also, if a preventive
maintenance schedule is not
followed, or is improperly carried
out, no amount of correct vehicle
operation will prevent malfunction.
If vehicle application, operation and
preventive maintenance schedules
and procedures are followed and
properly carried out, the life of the
vehicle will be greatly extended.
For example, regular attention to the
engine oil is essential. The oil level
must be periodically checked and oil
added whenever needed. Also, the
oil should be changed at the
intervals specified with the proper
quality and viscosity of oil. If your
engine should run excessively low
on oil or if the oil has lost its
lubricating qualities because of old
age, serious engine damage could
occur.
Maintenance Schedule Table
Letters Used to Indicate
Maintenance Service Types
I :
Inspect then clean, repair or
replace as necessary
A : Adjust
R : Replace
T : Tighten to the specified torque
L : Lubricate
C : Clean

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
Index 367
D
Damage Repair, Collision . . . . . . . 359
Danger, Warning, and Caution . . . . 3
Daytime Running Lamps (DRL)Indicator Light . . . . . . . . . . . . . . . . . . 69
Devices Auxiliary . . . . . . . . . . . . . . . . . . . . . . 107
Diesel Engine Engine Alarm andAutomatic Shutdown . . . . . . . . 164
Diesel Exhaust Fluid . . . . . . . . . . . . 180
Diesel Exhaust Fluid (DEF) Gauge . . . . . . . . . . . . . . . . . . . . . . . . . 60
Diesel Exhaust Fluid (DEF)
Warning Light . . . . . . . . . . . . . . . . . . 68
Diesel Particulate Filter . . . . . . . . . 171
Distracted Driving . . . . . . . . . . . . . . . 130
Dome Lamps . . . . . . . . . . . . . . . . . . . . 84
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Power Locks . . . . . . . . . . . . . . . . . . . . 21
Drive Belt Routing, Engine . . . . . . 355
Driver Behavior . . . . . . . . . . . . . . . . . 129
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . . . 70
Driving Better Fuel Economy . . . . . . . . . 129
Emergencies . . . . . . . . . . . . 145, 155 Driving (cont'd)
Hill and Mountain Roads . . . . . . 141
If the Vehicle is Stuck . . . . . . . . . 144
Wet Roads . . . . . . . . . . . . . . . . . . . 140
Winter . . . . . . . . . . . . . . . . . . . . . . . . 142
E
Electrical Equipment,
Add-On . . . . . . . . . . . . . . . . . . . . . . . 227
Electrical System
Overload . . . . . . . . . . . . . . . . . . . . . 277
Emergencies . . . . . . . . . . . . . . 145, 155
Engine Air Cleaner/Filter . . . . . . . . . . . . . 243
Alarm and Automatic
Shutdown . . . . . . . . . . . . . . . . . . . 164
Check Light (Malfunction Indicator) . . . . . . . . . . . . . . . . . . . . . . 61
Checks Before Operating . . . . . 166
Compartment Overview . . . . . . . 234
Coolant . . . . . . . . . . . . . . . . . . . . . . . 243
Coolant Temperature Gauge . . . . 60
Cover . . . . . . . . . . . . . . . . . . . . . . . . . 235
Drive Belt Routing . . . . . . . . . . . . 355
Exhaust . . . . . . . . . . . . . . . . . . . . . . 168
Heater . . . . . . . . . . . . . . . . . . . . . . . . 163
High Idle System . . . . . . . . . . . . . 165
Oil Pressure Light . . . . . . . . . . . . . . 67 Engine (cont'd)
Overheating . . . . . . . . . . . . . . . . . . 249
Reduced Power Light . . . . . . . . . . . 69
Running While Parked . . . . . . . . 170
Shutdown Warning Light . . . . . . . . 68
Engine Oil Level Indicator Light . . . . . . . . . . . . 67
Engines Diesel Fuel . . . . . . . . . . . . . . . . . . . 218
Exhaust Brake . . . . . . . . . . . . . . . . . . 213
Exhaust Brake Light . . . . . . . . . . . . . 65
Exhaust Fluid Diesel . . . . . . . . . . . . . . . . . . . . . . . . 180
Extender, Seat Belt . . . . . . . . . . . . . . 37
Exterior Lamp Controls . . . . . . . . . . 80
F
Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Filter, Engine Air Cleaner . . . . . . . . . . . 243
Fixed Mast Antenna . . . . . . . . . . . . . 90
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . 81
Flashers, Hazard Warning . . . . . . . 82
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . 300
Fluid Automatic Transmission . . . . . . 241
Brakes . . . . . . . . . . . . . . . . . . . . . . . . 258

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
Index 369
L
LampsCargo . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Cornering . . . . . . . . . . . . . . . . . . . . . . . 83
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Exterior Controls . . . . . . . . . . . . . . . . 80
Interior . . . . . . . . . . . . . . . . . . . . . . . . 277
License Plate . . . . . . . . . . . . . . . . . 276
Malfunction Indicator (CheckEngine) . . . . . . . . . . . . . . . . . . . . . . . 61
Roofmarker . . . . . . . . . . . . . . . . . . . 274
Sidemarker . . . . . . . . . . . . . . . . . . . 274
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . . . 36
Lighting Illumination Control . . . . . . . . . . . . . 83
Lights Antilock Brake System(ABS) Warning . . . . . . . . . . . . . . . . 64
Automatic Transmission
Fluid Temperature . . . . . . . . . . . . . 66
Battery Warning . . . . . . . . . . . . . . . . 61
Brake System Warning . . . . . . . . . 62
Check Engine (Malfunction Indicator) . . . . . . . . . . . . . . . . . . . . . . 61
Cruise Control . . . . . . . . . . . . . . . . . . 70
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . . . 69
Diesel Exhaust Fluid (DEF) . . . . . 68 Lights (cont'd)
Engine Oil Level Indicator . . . . . . 67
Engine Oil Pressure . . . . . . . . . . . . 67
Engine Shutdown Warning . . . . . 68
Exhaust Brake . . . . . . . . . . . . . . . . . . 65
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 81
High-Beam On . . . . . . . . . . . . . . . . . . 69
High/Low Beam Changer . . . . . . . 81
Idle Shutdown . . . . . . . . . . . . . . . . . . 68
Overdrive Off . . . . . . . . . . . . . . . . . . . 66
Reduced Engine Power . . . . . . . . 69
Seat Belt Reminders . . . . . . . . . . . . 60
Service Transmission
Warning . . . . . . . . . . . . . . . . . . . . . . . 65
Service Vehicle Soon . . . . . . . . . . . 62
Wait to Start . . . . . . . . . . . . . . . . . . . . 67
Loading the Vehicle . . . . . . . . . . . . . . 46
Locks Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Power Door . . . . . . . . . . . . . . . . . . . . . 21
M
Maintenance and CareAdditional . . . . . . . . . . . . . . . . . . . . . 336
Maintenance Schedule . . . . . . . . . 317 Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . 339
Malfunction Indicator Lamp . . . . . . 61 Messages
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . 74
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Heated . . . . . . . . . . . . . . . . . . . . . . . . . 22
N
New Vehicle Break-In . . . . . . . . . . . 156
Noise Control System . . . . . . . . . . 262
O
Odometer . . . . . . . . . . . . . . . . . . . . . . . . 58Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Oil
Engine . . . . . . . . . . . . . . . . . . . . . . . . 235
Pressure Light . . . . . . . . . . . . . . . . . . 67
Online Owner Center . . . . . . . . . . . 357
Operating Temperature . . . . . . . . . 162
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Overdrive Off . . . . . . . . . . . . . . . . . . . 206
Overdrive Off Light . . . . . . . . . . . . . . 66
Overheating, Engine . . . . . . . . . . . . 249
Overview Instrument Panel . . . . . . . . 8, 10, 11
Owner Checks and Services . . . . 330