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 149
If the vehicle must be driven on a
flooded road or is parked in an area
that becomes flooded, promptly
perform a check for the following
points:
.Effectiveness of the brakes
. Water-ingress or damage to
drum brakes, disc brakes
. Engine damage due to
water-ingress
. Shorting of electrical
components
. Oil level and degradation
(cloudiness) of the engine,
transmission, differential
. Greasing of each components
(lubrication)Steering
Do Not Leave the Steering
Wheel Fully Turned for a
Long Time
{Warning
If you leave the steering wheel
fully turned for a long time, the oil
in the power steering oil pump will
become extremely hot. This
would cause poor lubrication, oil
tank damage and seal
deterioration, leading to power
steering oil pump damage, power
steering unit damage and power
steering hose damage. As a
result the steering wheel could
become extremely hard to turn
and a fire or a crash could occur.
You and others could be seriously
injured.
Steering Wheel
If the steering parts have excess
play or looseness or if any abnormal
condition is noted, have the steering
system checked immediately.
Driving on Wet Roads
Driving on Slippery Surface or
Driving in Bad Weather (Rain,
Icy Roads, Snowy Roads, etc.)
In bad weather, visibility is reduced
and slippery road surfaces increase
stopping distances. Drive more
slowly than you would in good
weather. Also, avoid sharp turns of
the steering wheel and hard
braking. Use engine brakes together
with the foot brakes to decelerate.
Using the exhaust brake on a
slippery road surface could cause
the tires to slip.
You may not realize the surface is
slippery until the vehicle is skidding.
Learn to recognize warning clues—
such as enough water or ice on the
Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 151
.When going down on a steep
slope, avoid driving the vehicle
backward as much as possible.
Drive it forward slowly on the
down slope.
. Compared with forward
movement, the braking distance
of backward movement is longer,
and the steering response of
that is worse.
. If you must drive the vehicle
backward, drive it very carefully
and gradually by moving and
stopping repeatedly in order to
stop it any time.
Engine Brake : Engine brake is the
braking effect that occurs when you
release the accelerator pedal while
driving. The lower the gear, the
stronger the engine brake.
Exhaust Brake : The exhaust brake
is a system that closes the exhaust
pipe and uses the force of the
exhaust emissions to enhance the
effectiveness of engine brake. Overrunning :
An engine overrun is
an engine-speed increase that
causes the tachometer needle to
enter the red zone. It is dangerous
because it can cause engine failure.
Winter Driving
Recommendations for Driving
in Cold Regions
The following recommendations
apply to snowbound regions and to
mountainous regions, ski resorts
and other areas of extreme cold
and/or snowfall. Please follow them
also for reference in winter in other
regions.
For the sake of your vehicle, make
the winter preparations described in
the links below. Also have these
preparations made before driving to
a cold region.
See Engine Oil 0245.
See Engine Coolant 0253.
See Washer Fluid 0262.
See Battery - North America 0269.
When Ice Prevents You from
Putting Your Key in the Door
or Opening the Door
If you try to force the key into the
door, you could bend it. And if you
try to pull the door open with undue
force, the rubber seal around the
door could come unstuck or become
damaged. Use warm water to melt
the ice, then quickly wipe it away
and open the door.
If the wipers, electric door mirrors,
or power windows freeze up, also
use warm water to melt the ice and
then operate the system. Otherwise,
you could damage the mechanism
and drain the battery. After that,
wipe the water away.
Before Driving in Cold Regions
Getting In and Out of the Vehicle
The step can get icy in cold regions.
Be careful not to slip when getting in
and out of the vehicle.
Chevrolet Low Cab Forward 5.2L Diesel Engine 4500/5500 Series (GMNA-
Localizing-U.S.-12407814) - 2019 - crc - 12/13/17
Driving and Operating 155
SymptomCauseCorrective Action Reference
Engine does not
start Starter does not
turn over, or weak Discharged batteries Recharge or replace
See
Battery - North
America 0269
Battery terminals
detached, loose,
or corroded After repairing corroded
section, connect the
terminals firmly
-
Starter ground wire
terminal detached,
loose, or corroded After repairing corroded
section, connect the
terminals firmly
-
Engine oil viscosity
too high Change to an oil with
proper viscositySee
Engine Oil
0 245
Starter or electrical
system is 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 157
SymptomCauseCorrective Action Reference
Unsteady engine speed There is water or air in
the fuel system
Drain water from fuel
filter or bleed the systemSee
Running Out
of Fuel 0233 or
Water in Fuel
0 231
Fuel system is faulty
4-
White exhaust smoke Engine not sufficiently
warming up
Allow the engine to
warm up
-
Too much engine oil Correct the oil level See
Engine Oil
0 245
Engine Control system
faulty
4-
Fuel system faulty
4-
Exhaust injector
4-
Continuous idling for a
long period (more than
two hours) With the vehicle
stationary in a place
where it will not obstruct
traffic, hold down the
accelerator pedal and
check that white smoke
is not emitted
-
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 163
SymptomCauseCorrective Action Reference
Loud or abnormal
noises From the
transmission
Insufficient
transmission oil
Add oilSee
Automatic
Transmission Fluid
0 251
Transmission inner
components faulty
4-
From differential Insufficient differential
gear oil
Add oilSee
Rear Axle
(Gear Oil Viscosity
Chart) 0271 or
Rear Axle (Oil
Level Check) 0272
Differential inner
components faulty
4-
From the
suspension Spring pins, shackles,
or stoppers worn
4-
From the driveshaft Poor lubrication in each
component
Lubricate themSee
Owner Checks
and Services 0340
Splines or bearings worn
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 169
Starting the Engine
Do not keep the engine control
switch in the START position for
more than about 10 seconds.
Operating the starter for too long
might cause starter and battery
failure or may result in overheating.
When the engine does not start,
wait for 20 to 30 seconds and then
turn the engine control switch again.
Before starting the engine sit in the
driver seat, check that the parking
brake is firmly engaged, the selector
lever is in the P or N (P is preferred)
position and the shift indicator also
shows P or N, and firmly press the
brake pedal to start the engine.
When stopped on a slope, start the
engine with the selector lever in the
P position. SeeIgnition Positions
0 166.
1. Make sure that the selector lever is in the P or N position
and firmly press the brake
pedal.
2. When the engine control switch
is turned to the ON position,
the wait-to-start light comes on
and it goes out in about
1 second when the engine is
warm, to about 10 seconds
when the engine is cold.
3. After confirming that the wait-to-start light has gone out,
turn the engine control switch
to the START position to start
the engine. Release the engine
control switch as soon as the
engine starts.
4. Do not crank the engine for more than 10 seconds at a
time. If the engine does not
start, wait 20 to 30 seconds
with the engine control switch
in the LOCK or ACC position
before trying to start again. It is normal for the vacuum warning
buzzer to sound for a few seconds
after the engine has started.
After the engine has started, check
to be sure the selector lever is still
in the P position.
This engine has an automatic
warm-up system that increases
engine idle speed and applies the
exhaust brake. Allow sufficient time
to let the engine circulate lubricant
oil before driving. This usually
requires 30 seconds to 2 minutes
depending on ambient conditions.
See
Brake System Warning Light
(Parking Brake Light) 074.
The turbocharged engine should be
started in a way which ensures the
bearings supporting the rotating
parts of the turbocharger are
sufficiently lubricated. Do not race a
cold engine.
At low ambient temperatures, a cold
engine may emit more smoke than
usual.
Do not drive the truck until the
engine has had sufficient time to
circulate the lubricant oil. This