low oil pressure CHEVROLET LOW CAB FORWARD 2019 Owner's Manual

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
64 Instruments and Controls
Instruments and
Controls
Controls
Steering Wheel Adjustment . . . . 65
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Windshield Wiper/Washer . . . . . . 66
Power Outlets . . . . . . . . . . . . . . . . . 67
Warning Lights, Gauges, and
Indicators
Warning Lights, Gauges, andIndicators . . . . . . . . . . . . . . . . . . . . 68
Instrument Cluster . . . . . . . . . . . . . 69
Speedometer . . . . . . . . . . . . . . . . . . 70
Odometer . . . . . . . . . . . . . . . . . . . . . . 70
Trip Odometer . . . . . . . . . . . . . . . . . 70
Tachometer . . . . . . . . . . . . . . . . . . . . 71
Fuel Gauge . . . . . . . . . . . . . . . . . . . . 71
Engine Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . . . 72
Diesel Exhaust Fluid (DEF) Gauge . . . . . . . . . . . . . . . . . . . . . . . . 72
Seat Belt Reminders . . . . . . . . . . . 72
Battery Warning Light . . . . . . . . . . 73
Malfunction Indicator Lamp (Check Engine Light) . . . . . . . . . 73
Service Vehicle Soon Light . . . . 74 Brake System Warning Light
(Parking Brake Light) . . . . . . . . . 74
Antilock Brake System (ABS) Warning Light . . . . . . . . . . . . . . . . 76
Exhaust Brake Light . . . . . . . . . . . 77
Service Transmission Warning
Light . . . . . . . . . . . . . . . . . . . . . . . . . 77
Automatic Transmission Fluid Temperature Warning Light . . . 78
Overdrive Off Light . . . . . . . . . . . . . 78
Wait-to-Start Light . . . . . . . . . . . . . 79
Engine Oil Pressure Light . . . . . . 79
Engine Oil Level Indicator Light . . . . . . . . . . . . . . . . . . . . . . . . . 79
Diesel Exhaust Fluid (DEF) Warning Light . . . . . . . . . . . . . . . . 80
Engine Shutdown Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . 80
Idle Shutdown Light . . . . . . . . . . . . 80
Reduced Engine Power Light . . . . . . . . . . . . . . . . . . . . . . . . . 81
High-Beam On Light . . . . . . . . . . . 81
Daytime Running Lamps (DRL) Indicator Light . . . . . . . . . . . . . . . . 81
Cruise Control Light . . . . . . . . . . . 82
Information Displays
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . 82
Vehicle Messages
Vehicle Messages . . . . . . . . . . . . . 86
Warning Buzzers . . . . . . . . . . . . . . 91

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Instruments and Controls 79
Wait-to-Start Light
This light comes on when the
engine control switch is turned to
the ON position and goes out when
preheating is complete.
SeeStarting and Stopping the
Vehicle 0168.
Engine Oil Pressure Light
This light should come on briefly
when the engine control switch is
turned to the ON position, and then
should go out after the engine is
started. This light comes on when the
engine oil pressure has fallen below
the normal level while the engine is
running or the oil pressure across
the oil filter rises above the normal
level while the engine is running.
If the warning light comes on while
driving, immediately pull off to a
safe place and stop the engine.
Check the oil level in the engine
crankcase. If the oil level is normal,
restrictions are in the oil filter or
within the lubricating system. Have
the vehicle inspected at your dealer.
Do not run the engine with this light
on. It could damage the engine.
When this light comes on while
driving, a warning tone also sounds.
The oil level varies while the engine
is running right after it has stopped
or if the vehicle is on uneven
ground. As a result, the red engine
oil pressure warning light may
light up.
When checking the oil level, press
the engine oil level check switch on
level ground while the engine is
cool. The red engine oil pressurewarning light in combination with the
green engine oil level indicator light
can indicate if the engine oil level is
OK or low.
While driving, this light will also
activate the engine alarm and
automatic shutdown system.
See
Engine Oil Level Indicator Light
0 79 and Engine Oil 0245.
Engine Oil Level Indicator
Light
When the engine oil level check
switch is pushed with the engine
control switch in LOCK, the green
engine oil level indicator light will
come on if the engine oil level
is OK.
See Engine Oil Pressure Light 079
and Engine Oil 0245.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
148 Driving and Operating
Vapor Lock :If the brakes overheat
due to frequent use, the heat can
cause the brake fluid to boil so that
air bubbles are created in the brake
fluid. Pressing the brake pedal
simply compresses the air bubbles;
pressure is not transmitted to the
wheel cylinders, so the brakes'
effectiveness sharply deteriorates.
This phenomenon is called
vapor lock.
Even so, you should be very careful
when using engine braking in a low
gear because the engine is likely to
over-rev.
See Exhaust Brake 0222 and
Selector Lever 0214.
Do not adjust the exhaust brake
valve.
The engine should never be allowed
to exceed the governed speed.
Supplement the exhaust brake with
vehicle service brakes intermittently
and/or shift to higher transmission
gear to prevent engine overspeed.
A rule of thumb for gear selection is
that the vehicle should be driven
down a grade in the same gear that
would be used to climb that grade.{Warning
To reduce the risk of personal
injury, before going down a steep
or long grade, reduce speed, turn
on the exhaust brake and shift the
transmission to the next lower
gear. This will help control your
speed. Do not hold the brake
pedal down too long or too often
while going down a steep or long
grade. This could cause the
brakes to get hot and not to work
as well. As a result, the truck will
not slow down at the usual rate.
Failure to take these steps could
result in loss of vehicle control.
You and others could be seriously
injured.
Brake Effectiveness When the
Vehicle Has Been Driven on a
Flooded Road or Washed
{Warning
When the vehicle is driven on a
flooded road, parked on a flooded
road or washed, water can get
into the brakes and reduce their
effectiveness. If the brakes do not
work well afterward, drive slowly
and gently press the brake pedal
several times until the brakes dry
out and start working normally.
Always do this after driving
through water or washing the
vehicle to help reduce the risk of
personal injury. Before parking
the vehicle in winter, press the
brake pedal several times in the
same way to get rid of moisture in
the brakes. Otherwise, the
moisture in the brakes may freeze
and make the vehicle immovable.
You and others could be seriously
injured.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 159
SymptomCauseCorrective Action Reference
Engine is overheating No engine coolant Add engine coolant
See
Engine
Coolant 0253
Front of radiator is
clogged with dirt Wash clean with tap
waterSee
Exterior Care
0 317
Radiator cap not
sufficiently tightened Make sure it is firmly
tightened or replace the
radiator cap
-
Fan belt loose Adjust the tension or
replace the beltSee
Engine Drive
Belt Routing 0363
Engine coolant dirty
4-
Fan clutch is faulty
4-
Radiator cap dirty or
faulty Clean or replace -
Oil pressure is low Improper engine oil
viscosity
Change to an oil with
proper viscositySee
Engine Oil
0 245
Engine oil level too low Add engine oil See
Engine Oil
0 245
Engine inner
components are faulty
4-
Meter, indicator/warning
lights or switches faulty
4-

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 173
The engine block and oil pan
heaters are designed to warm the
block and oil pan areas that will let
the engine run faster. To use the
heaters:1. On single cab vehicles, tilt the cab.
2. Unwrap the electrical cord and remove the protective cap.
3. Plug the cord into any three-prong 110 volt outlet
(normal household current).
It may require several hours to
sufficiently heat the engine.
Outside temperature, oil
viscosity, etc., will affect how
long the block and oil pan
heater should remain plugged
in. Contact your dealer for the
conditions in your area.
4. After using the heater(s), be sure to restore the cord
properly, to help keep it away
from moving engine parts. If the cord is too short, use a heavy
duty, three-prong extension cord. Do
not use an extension cord such as
you would use for a lamp, because
the cord may overheat.
The engine should go through a
warm-up period to warm up the
engine oil before placing engine
under load. This will ensure proper
lubrication of the engine. See
Cab
Tilting 0243.
Engine Alarm and
Automatic Shutdown
If the system senses any of the
following conditions: high engine
temperature, low engine oil pressure
or low engine coolant, the
corresponding warning light and
engine alarm (shutdown) warning
light will come on. If the engine
alarm (shutdown) warning light
comes on, you will also hear a tone
alarm.
If your vehicle has the engine
shutdown feature, your engine will
shut down in 30 seconds.
Pull safely off the road and shut off
the engine. Do not start it until the
cause of the problem is known, and
the problem is fixed. However, if the
engine shuts down when you are
still in traffic, you can restart the
engine and get another 30 seconds
of operation. Do this only if you
have to, since there is a problem
that can harm the engine if it is not
fixed. See Engine Shutdown
Warning Light 080.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 175
4. Press the cruise control mainswitch to set it to ON. At this
time, the operation indicating
light will turn to green.
5. Turn and hold the cruise control set switch in the SET
position. After approximately
3 seconds the cruise control
set indicator light will begin to
flash slowly and the engine idle
will increase to 1,200 r/min.
Canceling High Idle Mode
Any of the following actions will
cancel high idle mode.
. The cruise control main switch is
set to OFF.
. The brake pedal is pressed.
. The parking brake is released.
. The selector lever is moved from
P (Park) or N (Neutral) position.
. The accelerator pedal is
pressed, accelerating the engine
beyond the engine speed
threshold. The cruise set indicator light will
stop flashing and the engine speed
will return to normal.
Engine Checks Before
Operating
Checks Before Operating
Allow the engine to warm up before
placing the engine under heavy load
driving. While the engine is warming
up under light load, the following
checks should be made:
1. Observe the red engine oil pressure warning light. The
light should go out when the
engine is running. If it stays on,
shut the engine off and find the
cause.
2. Look at the engine coolant temperature gauge. If the
gauge reaches the H (HOT)
area, stop the engine and find
the cause of the overheating.
3. Check that the battery warning light has gone out. The light
should go off and stay off at
normal idle speeds. If the light does not go out or comes on
during normal operation, have
the charging system checked.
4. Check that the brake low vacuum warning light is out
and that the vacuum buzzer is
not sounding. It is normal for
the warning buzzer to sound
for a few seconds after the
engine starts. If the light and
buzzer remain on, do not drive
the vehicle until the cause has
been found and corrected.
5. Look at the brake system warning light. It should be out
when the parking brake is
released and the engine is
running. If it stays on, it could
mean that the brake fluid level
is low. Check the brake fluid
reservoir. This condition must
be corrected before moving the
vehicle.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Vehicle Care 239
Vehicle Care
General Information
General Information . . . . . . . . . . 240
California Proposition65 Warning . . . . . . . . . . . . . . . . . 240
California Perchlorate Materials Requirements . . . . . 240
Accessories and Modifications . . . . . . . . . . . . . . . . 240
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 241
Cab Tilting . . . . . . . . . . . . . . . . . . . . 243
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 244
Engine Cover . . . . . . . . . . . . . . . . . 245
Engine Oil . . . . . . . . . . . . . . . . . . . . 245
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 251
Engine Air Cleaner/Filter . . . . . . 253
Engine Coolant . . . . . . . . . . . . . . . 253
Engine Overheating . . . . . . . . . . 259
Power Steering Fluid . . . . . . . . . 262
Washer Fluid . . . . . . . . . . . . . . . . . 262
Brakes . . . . . . . . . . . . . . . . . . . . . . . 263
Brake Fluid . . . . . . . . . . . . . . . . . . . 268
Battery - North America . . . . . . 269 Fuel Filter . . . . . . . . . . . . . . . . . . . . 270
Rear Axle (Gear Oil Viscosity
Chart) . . . . . . . . . . . . . . . . . . . . . . . 271
Rear Axle (Oil Level Check) . . . . . . . . . . . . . . . . . . . . . . 272
Noise Control System . . . . . . . . 272
Automatic Transmission Shift Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 274
Wiper Blade Replacement . . . . 275
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 277
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 277
Headlamps and Front Turn Signal . . . . . . . . . . . . . . . . . . . . . . . 280
Roofmarker Lamps . . . . . . . . . . . 284
Sidemarker Lamps (Including Turn Signal and Cornering
Lamps) . . . . . . . . . . . . . . . . . . . . . . 284
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 286
License Plate Lamp . . . . . . . . . . 286
Interior Lamps . . . . . . . . . . . . . . . . 287
Electrical System
Electrical System Overload . . . 287
Wheels and Tires
Wheels and Tires . . . . . . . . . . . . . 295
Tire Pressure . . . . . . . . . . . . . . . . . 307
Tire Rotation . . . . . . . . . . . . . . . . . 307
If a Tire Goes Flat . . . . . . . . . . . . 310
Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . . . 311
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . 315
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . 317
Interior Care . . . . . . . . . . . . . . . . . . 323

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
242 Vehicle Care
chock the wheels. It would be very
dangerous if the vehicle started
to move.
When performing work on the
electrical system, begin by turning
the engine control switch to the
"LOCK" position, wait at least
3 minutes, and then disconnect the
negative cable from the negative
terminal on battery. If the negative
cable is disconnected within
3 minutes, the engine control
module may malfunction.
When working on the fuel line or
fuel filter, remove the fuel tank filler
cap. The fuel system is under
pressure and the fuel will overspill
unless the pressure is relieved,
possibly leading to combustion or
a fire.
Do not make engine adjustments
yourself. Be sure to consult your
dealer.
Use only appropriate tools.Oils, brake fluid and engine coolant
have lubrication, cooling and rust
prevention functions. If these liquids
deteriorate through loss or
contamination, it will cause a
decline in the performance of the
parts and such problems as seizure
or malfunctioning. Replenish or
change these liquids when
performing the checks (daily and
periodic checks) as required by the
relevant regulations or in
accordance with the Maintenance
Schedule (when either the specified
driving distance or period of time,
whichever comes first, has expired).
Confirm that all systems and
components are normal after
performing the work.
Do not leave the removed parts or
tools in the engine compartment.
They could damage the equipment if
caught in the belts or other moving
components.
Dirty water, dirt and other impurities
seriously impair the effectiveness of
the oil, grease and fluids, and
damage the parts. Exercise all due
caution to prevent waste or otherrefuse from coming in contact with
parts or materials that have been
removed when changing or
replenishing them.
Do not step on the engine or climb
onto it. You could cause an engine
failure by, for example, damaging
the cylinder head cover or various
connectors.
Electric Welding
Careless electric welding of vehicle
parts can cause welding current to
flow back through the vehicle’s
ground circuit and damage electrical
and electronic parts so that they do
not function normally. Whenever
electric welding is necessary,
consult your dealer.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
246 Vehicle Care
and the oil should be changed
regularly according to the
Maintenance Schedule.
The engine oil performs the
following important functions:
.It prevents engine parts from
becoming worn.
. It cools engine parts.
. It cleans engine parts.
. It seals the combustion
chambers and prevents rust.
Replace the engine oil at regular
intervals.
When particulate matter (PM) has
accumulated to a preset level in the
diesel particulate filter (DPF), the
filter is automatically regenerated
through combustion. To make this
regeneration (combustion) possible,
a small amount of fuel is injected
into the engine combustion chamber
after firing. This causes fuel to
gradually become mixed with the
engine oil, and the engine oil level
may rise beyond the original level.
This does not indicate a malfunction
of the engine.Access to the Engine
Single Cab Model
Access to the engine oil dipstick is
located on the engine left side after
tilting the cab. See Cab Tilting
0 243.
Crew Cab Model
The engine oil dipstick is under the
engine inspection sub cover located
beneath the driver's seat.
Checking the Engine Oil Level
Press the engine oil level check
switch. If engine oil level is low the
red oil pressure warning light will
turn on. If the engine oil level is
above the "OK", the green oil level
indicator will turn on.
The oil level varies while the engine
is running, right after it is stopped,
and on sloping ground. When
checking the oil level, be sure the
vehicle is on level ground while the
engine is cool.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Vehicle Care 259
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.