engine coolant Ram 2500 2020 User Guide

218STARTING AND OPERATING
5. After engine start-up, check to see that
there is oil pressure.
6. Release the parking brake and drive.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
The engine will not automatically crank after
the engine “Wait To Start” telltale goes off if
a door or the hood is ajar.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least
5 seconds and then back ON. Repeat steps
1 through 7 of “Keyless Enter-N-Go Starting Procedure – Engine Manifold Air Tempera
-
ture Below 66° F (19° C).”
Extreme Cold Weather
The Cummins® Turbo Diesel engine is
equipped with several features designed to
assist cold weather starting and operation:
The engine block heater is a resistance
heater installed in the water jacket of the
engine just above and behind the oil filter. It
requires a 110–115 Volt AC electrical outlet
with a grounded, three-wire extension cord.
NOTE:
The engine block heater cord is a factory
installed option. If your vehicle is not equipped,
heater cords are available from an authorized
Mopar dealer.
A 12 Volt heater built into the fuel filter hous -
ings aid in preventing fuel gelling. It is
controlled by a built-in thermostat.
A intake air heater system both improves
engine starting and reduces the amount of
white smoke generated by a warming engine.
Normal Starting Procedure — Engine
Manifold Air Temperature Above 66° F
(19° C)
Observe the instrument panel cluster lights
when starting the engine.

1. Always apply the parking brake.

2. Shift into PARK for an automatic transmis -
sion.
3. Place the ignition switch in the ON position and watch the instrument panel cluster
lights.
4. Place the ignition switch in the START posi -
tion and crank the engine. Do not press the
accelerator during starting.
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage. Refer to “Draining Fuel/
Water Separator Filter” in “Servicing And
Maintenance” for further information.

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STARTING AND OPERATING219
5. Check that the oil pressure warning light
has turned off.
6. Release the parking brake.
Starting Procedure — Engine Manifold Air
Temperature 0°F To 66°F (–18°C to 19°C)
NOTE:
The temperature displayed in the instrument
cluster does not necessarily reflect the engine
manifold air temperature. Refer to “Instrument
Cluster Display” in “Getting To Know Your
Instrument Panel” for further information.
When engine temperatures fall below 66°F
(19°C) the “Wait To Start Light” will remain on
indicating the intake air heater system is active.
Follow the steps in the “Normal Starting” proce -
dure except:
1. The “Wait To Start” telltale will remain on
for a period of time that varies depending
on the engine temperature.

2. While the “Wait To Start” telltale is on, the instrument cluster will additionally display a
gauge or bar whose initial length represents
the full “Wait To Start” time period. Its
length will decrease until it disappears
when the “Wait To Start” time has elapsed.
3. After the “Wait To Start” telltale goes off, place the ignition switch in the START posi -
tion. Do not press the accelerator during
starting. 4. After engine start-up, check that the oil
pressure warning light has turned off.
5. Release the parking brake and drive.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
Automatic equipped vehicles with optional
Keyless Enter-N-Go – If the start button is
pushed once while in park with the ignition
off and driver’s foot on the brake pedal, the
vehicle will automatically crank and start
after the Wait to Start time has elapsed. If it
is desired to abort the start process before it
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
CAUTION!
If the “Water in Fuel Indicator Light” remains
on, DO NOT START the engine before you
drain the water from the fuel filters to avoid
engine damage. Refer to “Draining Fuel/
Water Separator Filter” in “Servicing And
Maintenance” for further information.
CAUTION!
Do not crank engine for more than 25 seconds
at a time or starter motor damage may result.
Turn the ignition switch to the OFF position and
wait at least two minutes for the starter to cool
before repeating start procedure.
5

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220STARTING AND OPERATING
completes, the driver’s foot should be fully
removed from the brake pedal prior to
pushing the start button again in order for the
ignition to move directly to off.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least five
seconds and then back ON. Repeat steps
1 through 5 of “Starting Procedure – Engine
Manifold Air Temperature Below 66°F
(19°C).”
Starting Procedure — Engine Manifold Air
Temperature Below 0°F (-18°C)
In extremely cold weather below 0°F (-18°C) it
may be beneficial to cycle the intake air heater
twice before attempting to start the engine. This
can be accomplished by turning the ignition OFF
for at least 5 seconds and then back ON after
the “Wait To Start” telltale has turned off, but
before the engine is started. However, exces -
sive cycling of the intake air heater will result in
damage to the heater elements or reduced
battery voltage. NOTE:
If multiple pre-heat cycles are used before
starting, additional engine run time may be
required to maintain battery state of charge at a
satisfactory level.

1. If the engine stalls after the initial start, the
ignition must be turned to the OFF position
for at least five seconds and then to the ON
position to recycle the intake air heater.

NOTE:
Excessive white smoke and poor engine perfor -
mance will result if intake air heater are not
recycled.
2. Heat generated by the intake air heater dissipates rapidly in a cold engine. If more
than two minutes pass between the time
the “Wait To Start” telltale turns off and the
engine is started, recycle the intake air
heater by turning the ignition switch to the
OFF position for at least five seconds and
then back ON.
3. If the vehicle is driven and vehicle speed exceeds 19 mph (31 km/h) before the
intake air heater post-heat (after start) cycle
is complete, the intake air heater will shut
off. 4. If the engine is cranked for more than
10 seconds, the post-heat cycle will turn off.
NOTE:
Engine idle speed will automatically increase
to 1,000 RPM and engage the Variable
Geometry Turbocharger at low coolant
temperatures to improve engine warm-up.
When a diesel engine is allowed to run out of
fuel or the fuel gels at low temperatures, air
is pulled into the fuel system. If your engine
has run out of fuel, refer to “Dealer Service/
Priming If The Engine Has Run Out Of Fuel” in
“Servicing And Maintenance” for further
information.
If the engine stalls, or if the ignition switch is
left ON for more than two minutes after the
“Wait To Start” telltale goes out, reset the
intake air heater by turning the ignition
switch to the OFF position for at least 5
seconds and then back ON. Repeat steps
1 through 5 of “Starting Procedure – Engine
Manifold Air Temperature Below 66°F
(19°C).”

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224STARTING AND OPERATING
Your vehicle is equipped with an engine warm
up protection feature that may limit engine
performance after cold starting at low ambient
temperatures. The length of time engine speed
is limited is dependent upon engine coolant
temperature. Engine speed may be briefly
limited to 1000 RPM after starting with coolant
temperature below freezing conditions, and
may be limited to 1000 RPM for up to approxi -
mately 2 minutes under more severe cold
conditions.
NOTE:
If ambient temperatures are low and the
coolant temperature is below 180°F (82°C),
the engine idle speed will slowly increase to
1,000 RPM after two minutes of idle, if the
following conditions are met:
Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will
greatly improve warm up rate and will help
keep the engine close to operating tempera -
ture during extended idle.
Engine Idling
Avoid prolonged idling, long periods of idling
may be harmful to your engine because
combustion chamber temperatures can drop so
low that the fuel may not burn completely.
Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves,
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine.
If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for
more than 2 hours, the system will automati -
cally enter an emissions operating mode that
will increase the engine idle speed to 900 RPM.
While in this mode, which is designed to help
maintain the diesel particulate filter, the engine
idle speed will return to normal when the brake
pedal is applied. A small change in engine tone
or a slight change in engine performance while
accelerating may also be noticeable at speeds
below 20 mph (32 kmh). This operating mode
may last for up to an hour of idle time, or around
20 minutes of driving time.
Your truck may have been ordered with an
optional voltage monitoring idle up feature. If a
load is placed on the electrical system while the truck is in park, this feature will attempt to
maintain normal system voltage by automati
-
cally increasing engine idle speed. You may
notice several consecutive increases in idle
speed, up to a maximum of 1,450 RPM, as the
system will attempt to utilize the smallest
increase in idle speed necessary to maintain
normal system voltage. The idle speed will
return to normal when either the electrical load
is removed, or when the brake pedal is applied.
NOTE:
For instrument cluster display messages
related to the vehicle's exhaust system, refer to
“Instrument Cluster Display” in “Getting To
Know Your Instrument Panel” for further infor -
mation.
Idle-Up Feature
The driver-controlled high idle speed feature will
help increase cylinder temperatures and
provide additional cab heat, however, excessive
idling may still cause the exhaust aftertreat -
ment system to not properly regenerate.
Extended periods of idle time should be
avoided.
The Idle-Up feature uses the Speed Control
switches to increase engine idle speed and
quickly warm the vehicle's interior.

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STARTING AND OPERATING225

1. With the transmission in PARK, the parking
brake applied, and the engine running,
push the speed control switch to the ON
position, then push the SET switch.

2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the
ACCEL/RESUME switch and the idle speed
will increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the
DECEL switch and the idle speed will
decrease to approximately 1,100 RPM.
3. To cancel the Idle–Up feature, either push the CANCEL switch, push the ON/OFF
switch, or press the brake pedal.
Noise
Diesel engines can create noises that may
seem concerning. The nature of a diesel engine
is compression ignition where compressed air and fuel are mixed and ignited. Weather, baro
-
metric pressure, altitude, and temperature will
affect how fuel is ignited in the engine. Engines
will sound different from day to day or previous
model years. Clicking, ticking, or light knocking
is normal and will change from day to day, as
the engine breaks in, and can vary with changes
in ambient temperature. Clicking sound from
under the hood shortly after vehicle shutdown is
normal as actuators such as the EGR valve are
cycled. Fuel pump noise may increase during
low speed/light load conditions when ambient
temperature is above 100°F (38°C), and when
fuel tank level is below 10% which is a normal
condition of the fuel system and controls
strategy. Diesel equipped vehicles also have an
exhaust after-treatment system to reduce emis -
sions utilizing a DPF (refer to “Odor” in this
section for further information) and a Selective
Reduction Catalyst (SCR). The SCR reduces
Nitrogen Oxides (NOx) using the Diesel Exhaust Fluid (DEF) system. DEF is injected directly into
the SCR through a dosing module. This process
will create a clicking sound and at times, will
make noise even with the vehicle shut off. This
is normal as the DEF dosing module is purging
DEF. If at any time the check engine light is on,
please visit an authorized dealer.
Stopping The Engine
Idle the engine a few minutes before routine
shutdown. After full load operation, idle the
engine three to five minutes before shutting it
down. This idle period will allow the lubricating
oil and coolant to carry excess heat away from
the combustion chamber, bearings, internal
components, and turbocharger. This is espe
-
cially important for turbocharged, charge
air-cooled engines. Refer to the following chart
for proper engine shutdown:
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown
Stop and Go EmptyCoolLess than One
Stop and Go Medium -One
Highway Speeds MediumWarmTwo
5

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226STARTING AND OPERATING
Idle Shutdown
This feature can be enabled so that the truck
will automatically shutdown when the truck has
been idling for a set period of time when the
engine is at operating temperature. Idle time
can be set in 5 minute increments between 5
and 60 minutes. See an authorized dealer to
enable this feature.
NOTE:
The idle shut down timer is disabled while the
PTO is active.
Programmable Maximum Vehicle Speed
This feature allows the owner to set a maximum
vehicle speed for the vehicle. The 2500 and
3500 Series maximum vehicle speed can be set
between 40 mph (64 km/h) and 87 mph
(140 km/h). The 4500/5500 Series maximum
vehicle speed can be set between 40 mph (64 km/h) and 85 mph (136 km/h). See an
authorized dealer to enable this feature.
NOTE:
DO NOT set the maximum vehicle speed to a
value greater than what the vehicle tires are
rated for.
Operating Precautions
Avoid Overheating The Engine
The temperature of the engine coolant (anti
-
freeze) (a mixture of 50% ethylene-glycol and
50% water) must not exceed the normal range
of the temperature gauge 240°F (116°C) with
a 21 psi (145 kPa) coolant pressure cap.
Usually the engine coolant (antifreeze)
temperature indicated during operation will be
to the left of center in the normal range of the
gauge.
Avoid Low Coolant Temperature Operation
Continual operation at low engine coolant (anti -
freeze) temperature below the normal range on
the gauge 140°F (60°C) can be harmful to the
engine. Low engine coolant (antifreeze)
temperature can cause incomplete combustion
which allows carbon and varnish to form on
piston rings and injector nozzles. Also, the
unburned fuel can enter the crankcase, diluting
the lubricating oil and causing rapid wear to the
engine.
Cooling System Tips
To reduce potential for engine and transmission
overheating in high ambient temperature condi -
tions, take the following actions:
City Driving — When stopped, shift the trans -
mission into NEUTRAL and increase engine
idle speed.
Highway Driving — Reduce your speed.
City Traffic
Maximum GCWR -Three
Highway Speeds Maximum GCWR -Four
Uphill Grade Maximum GCWR HotFive
Driving Condition Load Turbocharger Temperature Idle Time (min.) Before Engine
Shutdown

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STARTING AND OPERATING227
Up Steep Hills — Select a lower transmission
gear.
Air Conditioning — Turn it off temporarily.
Do Not Operate The Engine With Low Oil
Pressure
When the engine is at normal operating
temperature, the minimum oil pressures
required are:
Do Not Operate The Engine With Failed Parts
All engine failures give some warning before the
parts fail. Be on the alert for changes in perfor -
mance, sounds, and visual evidence that the
engine requires service. Some important clues
are:
Engine misfiring or vibrating severely.
Sudden loss of power.
Unusual engine noises.
Fuel, oil or coolant leaks.
Sudden change, outside the normal oper -
ating range, in the engine operating tempera -
ture.
Excessive smoke.
Oil pressure drop.
ENGINE BLOCK HEATER — GAS ENGINE (IF
EQUIPPED)
The engine block heater warms the engine, and
permits quicker starts in cold weather. Connect
the cord to a standard 110-115 Volt AC elec -
trical outlet with a grounded, three-wire exten -
sion cord.
The engine block heater cord is routed through
the grille by the right front tow hook.
It includes a removable cap that is secured by a
tethered strap. It also has a c-clip that is used
for storage when not in use for the winter
months. During winter months, remove the
heater cord wiring assembly from itself on the
c-clip. The engine block heater must be plugged in at
least one hour to have an adequate warming
effect on the engine.
ENGINE BLOCK HEATER — DIESEL ENGINE
(IF EQUIPPED)
The engine block heater warms engine coolant
and permits quicker starts in cold weather.
Connect the heater cord to a ground-fault inter
-
rupter protected 110–115 Volt AC electrical
outlet with a grounded, three-wire extension
cord.
The engine block heater cord is routed under
the hood to the right side and can be located
just behind the grille near the headlamp.
NOTE:
The engine block heater cord is a factory
installed option. If your vehicle is not equipped,
heater cords are available from an authorized
Mopar dealer.
Idle 700 to 800 RPM 10 psi (69 kPa)
Full speed and load 30 psi (207 kPa)CAUTION!
If oil pressure falls to less than normal
readings, shut the engine off immediately.
Failure to do so could result in immediate and
severe engine damage.
WARNING!
Remember to disconnect the engine block
heater cord before driving. Damage to the
110-115 Volt electrical cord could cause
electrocution.
5

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228STARTING AND OPERATING
The block heater must be plugged in at least
one hour to have an adequate warming effect
on the coolant.
NOTE:
The block heater will require 110 Volts AC and
6.5 Amps to activate the heater element.
Block Heater Usage
For ambient temperatures below 0°F (-18°C),
engine block heater usage is recommended.
For ambient temperatures below –20°F
(-29°C), engine block heater usage is required.
ENGINE BREAK-IN RECOMMENDATIONS —
GAS ENGINE
A long break-in period is not required for the
engine and drivetrain (transmission and axle) in
your vehicle.
Drive moderately during the first 300 miles
(500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are
desirable.
While cruising, brief full-throttle acceleration
within the limits of local traffic laws contributes
to a good break-in. Wide-open throttle accelera-
tion in low gear can be detrimental and should
be avoided.
The engine oil installed in the engine at the
factory is a high-quality energy conserving type
lubricant. Oil changes should be consistent with
anticipated climate conditions under which
vehicle operations will occur. For the recom
-
mended viscosity and quality grades, refer to
“Fluids And Lubricants” in “Technical Specifica-
tions”.
NOTE:
A new engine may consume some oil during its
first few thousand miles (kilometers) of opera -
tion. This should be considered a normal part of
the break-in and not interpreted as a problem.
Please check your oil level with the engine oil indicator often during the break in period. Add
oil as required.
ENGINE BREAK-IN RECOMMENDATIONS —
DIESEL ENGINE
The Cummins® Turbo Diesel engine does not
require a break-in period due to its construction.
Normal operation is allowed, providing the
following recommendations are followed:
Warm up the engine before placing it under
load.
Do not operate the engine at idle for
prolonged periods.
Use the appropriate transmission gear to
prevent engine lugging.
Observe vehicle oil pressure and tempera
-
ture indicators.
Check the coolant and oil levels frequently.
Vary throttle position at highway speeds
when carrying or towing significant weight.
WARNING!
Remember to disconnect the cord before
driving. Damage to the 110–115 Volt
electrical cord could cause electrocution.
CAUTION!
Never use Non-Detergent Oil or Straight
Mineral Oil in the engine or damage may
result.

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STARTING AND OPERATING231
(Continued)
(Continued)
NOTE:
For optimum braking power it is recommended
to use the exhaust brake while in TOW/HAUL
mode.
The exhaust brake feature can also be used to
reduce the engine warm up time. To use the
exhaust brake as a warm-up device, the vehicle
must be stopped or moving less than 5 mph
(8 km/h), the "Exhaust Brake Indicator" must be
on, and the coolant temperature must be below
180°F (82°C) and ambient temperature below
60°F (16°C).
Automatic “Smart” Exhaust Brake
Automatic “Smart” Exhaust Brake technology
delivers smoother, less aggressive exhaust
braking characteristics during downhill
descents. Although it can apply full exhaust
braking force if needed, Automatic “Smart”
Exhaust Brake may not apply obvious braking if
the vehicle speed is not increasing. Automatic
“Smart” Exhaust Brake is intended to maintain
vehicle speed, while Full Exhaust Brake is
intended to reduce vehicle speed. Automatic “Smart” Exhaust Brake can be
enabled by pushing the exhaust brake button
(on the center stack) again anytime after the
normal Full Exhaust Brake has been turned on.
The “Exhaust Brake Indicator” in the instrument
cluster display will change from Yellow to Green
when Automatic “Smart” Exhaust Brake is
enabled. Pushing the exhaust brake button
again will toggle the exhaust brake mode to off.
AUTOMATIC TRANSMISSION
WARNING!
Never use the PARK position as a substi
-
tute for the parking brake. Always apply the
parking brake fully when exiting the vehicle
to guard against vehicle movement and
possible injury or damage.
Your vehicle could move and injure you and
others if it is not in PARK. Check by trying to
move the transmission gear selector out of
PARK with the brake pedal released. Make
sure the transmission is in PARK before
exiting the vehicle.
The transmission may not engage PARK if
the vehicle is moving. Always bring the
vehicle to a complete stop before shifting to
PARK, and verify that the transmission gear
position indicator solidly indicates PARK (P)
without blinking. Ensure that the vehicle is
completely stopped, and the PARK position
is properly indicated, before exiting the
vehicle.
It is dangerous to shift out of PARK or
NEUTRAL if the engine speed is higher than
idle speed. If your foot is not firmly pressing
the brake pedal, the vehicle could accel -
erate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and your
foot is firmly pressing the brake pedal.
WARNING! (Continued)
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242STARTING AND OPERATING
To exit ERS mode, simply push and hold the ERS
(+) switch until the gear limit display disappears
from the instrument cluster.
NOTE:
To select the proper gear position for maximum
deceleration (engine braking), simply push and
hold the ERS (-) switch. The transmission will
shift to the range from which the vehicle can
best be slowed down.
Overdrive Operation
The automatic transmission includes an elec -
tronically controlled Overdrive (fifth and sixth
gears). The transmission will automatically shift
into Overdrive if the following conditions are
present:
The gear selector is in the DRIVE position.
The transmission fluid has reached an
adequate temperature.
The engine coolant has reached an adequate
temperature.
The vehicle speed is sufficiently high.
The driver is not heavily pressing the acceler -
ator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer,
carrying a heavy load, etc., and frequent trans -
mission shifting occurs, push the TOW/HAUL switch to activate TOW/HAUL mode. This will
improve performance and reduce the potential
for transmission overheating or failure due to
excessive shifting. When operating in TOW/
HAUL mode, transmission upshifts are delayed,
and the transmission will automatically down
-
shift (for engine braking) when the throttle is
closed and/or during steady braking maneu -
vers.

TOW/HAUL Switch

The “TOW/HAUL Indicator Light” will illuminate
in the instrument cluster to indicate that TOW/
HAUL mode has been activated. Pushing the
switch a second time restores normal opera -
tion. Normal operation is always the default at
engine start-up. If TOW/HAUL mode is desired,
the switch must be pushed each time the
engine is started.
WARNING!
Do not downshift for additional engine
braking on a slippery surface. The drive
wheels could lose their grip and the vehicle
could skid, causing a collision or personal
injury.
Transmis -
sion Gear
Limit Dis -
play 1 2 3 4 5 6 D
Actual
Gear(s)
Allowed
1 1-2 1-3 1-4 1-5 1-6 1-6
CAUTION!
When using ERS for engine braking while
descending steep grades, be careful not to
overspeed the engine. Apply the brakes as
needed to prevent engine overspeed.

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