2020 JEEP WRANGLER UNLIMITED coolant temperature

45
The temperature can be displayed in U.S.
or Metric units by selecting the U.S./
Metric customer-programmable feature.
Refer to the “Uconnect Settings” in
“Multimedia” in the Owner’s Manual for
further information.
To provide you with maximum comfort in the
Automatic mode during cold start-ups, the
blower fan will remain on low until the
engine warms up. The blower will increase in
speed and transition into Auto mode.
Manual Operation Override
This system offers a full complement of
manual override features. The AUTO symbol
in the front ATC display will be turned off
when the system is being used in the manual
mode.
Operating Tips
Summer Operation
The engine cooling system must be
protected with a high-quality antifreeze
coolant to provide proper corrosion protec -
tion and to protect against engine over -
heating. OAT coolant (conforming to
MS.90032) is recommended.
Winter Operation
To ensure the best possible heater and
defroster performance, make sure the engine
cooling system is functioning properly and
the proper amount, type, and concentration
of coolant is used. Use of the Air Recircula -
tion mode during Winter months is not
recommended, because it may cause window
fogging.
Vacation/Storage
Before you store your vehicle, or keep it out
of service (i.e., vacation) for two weeks or
more, run the air conditioning system at idle
for about five minutes, in fresh air with the
blower setting on high. This will ensure
adequate system lubrication to minimize the
possibility of compressor damage when the
system is started again.
Window Fogging
Vehicle windows tend to fog on the inside in
mild, rainy, and/or humid weather. To clear
the windows, select Defrost or Mix mode and
increase the front blower speed. Do not use
the Recirculation mode without A/C for long
periods, as fogging may occur.
Outside Air Intake
Make sure the air intake, located directly in
front of the windshield, is free of obstruc -
tions, such as leaves. Leaves collected in the
air intake may reduce airflow, and if they
enter the plenum, they could plug the water
drains. In Winter months, make sure the air
intake is clear of ice, slush, and snow.
CAUTION!
Failure to follow these cautions can cause
damage to the heating elements:
Use care when washing the inside of the
rear window. Do not use abrasive window
cleaners on the interior surface of the
window. Use a soft cloth and a mild
washing solution, wiping parallel to the
heating elements. Labels can be peeled
off after soaking with warm water.
Do not use scrapers, sharp instruments,
or abrasive window cleaners on the inte-
rior surface of the window.
Keep all objects a safe distance from the
window.
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67
— Engine Coolant Temperature Warning
Light
This warning light warns of an overheated
engine condition. If the engine coolant
temperature is too high, this indicator will
illuminate and a single chime will sound. If
the temperature reaches the upper limit, a
continuous chime will sound for four
minutes or until the engine is able to cool;
whichever comes first.
If the light turns on while driving, safely pull
over and stop the vehicle. If the A/C system
is on, turn it off. Also, shift the transmission
into Park and allow the vehicle to sit idle
(propulsion system active). If the tempera -
ture reading does not return to normal, turn
the engine off immediately and call for
service.
Refer to “If Your Engine Overheats” in “In
Case Of Emergency” for further information.
— Hood Open Warning Light
This indicator will illuminate when the hood
is ajar/open or not fully closed.
NOTE:
If the vehicle is moving, there will also be a
single chime.
— Oil Pressure Warning Light
This warning light will illuminate to indicate
low engine oil pressure. If the light turns on
while driving, stop the vehicle, shut off the
engine as soon as possible, and contact an
authorized dealer. A chime will sound when
this light turns on.
Do not operate the vehicle until the cause is
corrected. This light does not indicate how
much oil is in the engine. The engine oil level
must be checked under the hood.
— Oil Temperature Warning Light
This warning light will illuminate to indicate
the engine oil temperature is high. If the
light turns on while driving, stop the vehicle
and shut off the engine as soon as possible.
Wait for oil temperature to return to normal
levels.
— Seat Belt Reminder Warning Light
This warning light indicates when the driver
or passenger seat belt is unbuckled. When
the ignition is first placed in the ON/RUN or
ACC/ON/RUN position and if the driver’s
seat belt is unbuckled, a chime will sound
and the light will turn on. When driving, if the driver or front passenger seat belt
remains unbuckled, the Seat Belt Reminder
Light will flash or remain on continuously
and a chime will sound.
Refer to “Occupant Restraint Systems” in
“Safety” for further information.
— Rear Seat Belt Reminder Warning Light
— If Equipped
This light indicates when a rear seat belt is
unbuckled in the second row. When the igni -
tion is first placed in the ON/RUN or ACC/
ON/RUN position, and if a seat belt in the
second row is unbuckled, a light corre -
sponding to the specific seat will turn on in
the upper right portion of the instrument
cluster display, momentarily replacing the
configurable corner information. If a second
row seat belt that was buckled at the start of
the trip is unbuckled, the Rear Seat Belt
Reminder Light will change from green to red
and a single chime will sound.
Refer to “Occupant Restraint Systems” in
“Safety” for further information.
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STARTING AND OPERATING
142
Diesel Engine Idling — In Cold Weather
Avoid prolonged idling in ambient tempera-
tures below 0°F (-18°C). 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
and injector nozzles. Also, the unburned fuel
can enter the crankcase, diluting the oil and
causing rapid wear to the engine.
Stopping the Engine
The following chart should be used as a
guide in determining the amount of engine
idle time required to sufficiently cool down
the turbocharger before shut down,
depending upon the type of driving and the
amount of cargo.
Before turning off your turbo diesel engine,
always allow the engine to return to normal idle
speed and run for several seconds. This
ensures proper lubrication of the turbocharger. This is particularly necessary after any period
of hard driving.
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 lubri
-
cating oil and coolant to carry excess heat
away from the combustion chamber, bear -
ings, internal components, and turbo -
charger. This is especially important for
turbocharged, charge air cooled engines.
Turbocharger "Cool Down" Chart
Driving
Conditions Load
Turbocharger
Temperature Idle Time (In Minutes)
Before Shut Down
Stop & Go EmptyCoolLess than 1
Stop & Go Medium Warm1
Highway Speeds MediumWarm2
City Traffic Max. GCWR Warm3
Highway Speeds Max. GCWR Warm4
Uphill Grade Max. GCWR Hot5
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 142

IN CASE OF EMERGENCY
204
IF YOUR ENGINE
OVERHEATS
In any of the following situations, you can
reduce the potential for overheating by
taking the appropriate action.
On the highways — slow down.
In city traffic — while stopped, shift trans-
mission into NEUTRAL (N), but do not
increase engine idle speed.NOTE:
There are steps that you can take to slow
down an impending overheat condition:
If your Air Conditioner (A/C) is on, turn it
off. The A/C system adds heat to the
engine cooling system and turning the A/C
off can help remove this heat.
You can also turn the temperature control
to maximum heat, the mode control to
floor and the blower control to high. This
allows the heater core to act as a supple-
ment to the radiator and aids in removing
heat from the engine cooling system.
MANUAL PARK RELEASE
CAUTION!
Driving with a hot cooling system could
damage your vehicle. If the temperature
gauge reads HOT (H), pull over and stop
the vehicle. Idle the vehicle with the air
conditioner turned off until the pointer
drops back into the normal range. If the
pointer remains on HOT (H), and you hear
continuous chimes, turn the engine off
immediately and call for service.
WARNING!
You or others can be badly burned by hot
engine coolant (antifreeze) or steam from
your radiator. If you see or hear steam
coming from under the hood, do not open
the hood until the radiator has had time to
cool. Never try to open a cooling system
pressure cap when the radiator or coolant
bottle is hot.
WARNING!
Always secure your vehicle by fully
applying the parking brake before
activating the Manual Park Release. In
addition, you should be seated in the
driver’s seat with your foot firmly on the
brake pedal when activating the Manual
Park Release. Activating the Manual Park
Release will allow your vehicle to roll away
if it is not secured by the parking brake, or
by proper connection to a tow vehicle.
Activating the Manual Park Release on an
unsecured vehicle could lead to serious
injury or death for those in or around the
vehicle.
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SERVICING AND MAINTENANCE
216
Severe Duty Conditions
Change the engine oil and engine oil filter at
every 4,500 miles (7,500 km) or 6 months
if using your vehicle under any of the
following severe duty conditions:
Stop and go driving.
Driving in dusty conditions.
Short trips of less than 10 miles (16 km).
Trailer towing.
Taxi, police, or delivery service (commer-
cial service).
Off-road or desert operation.
Scheduled Servicing — Diesel Engine
Your vehicle is equipped with an automatic
oil change indicator system. The oil change
indicator system will remind you that it is
time to take your vehicle in for engine oil
replacement.
On vehicles equipped with instrument
cluster display, “Oil Change Required” will
be displayed and a single chime will sound,
indicating that an oil change is necessary.
On non-instrument cluster display equipped
vehicles, “Change Oil” will flash in the
instrument cluster odometer and a single
chime will sound, indicating that an oil
change is necessary.

Based on engine operation conditions, the oil
change indicator message will illuminate. This
means that service is required for your vehicle.
Operating conditions such as frequent
short-trips, trailer tow, extremely hot or cold
ambient temperatures will influence when the
“Oil Change Required” message is displayed. Severe Operating Conditions can cause the
change oil message to illuminate as earlier than
specified. Have your vehicle serviced as soon
as possible, within the next 500 miles
(805 km).

NOTE:
The actual interval for changing engine oil
and replacing the engine oil filter depends
on the vehicle usage conditions, and is
signaled by the warning light or message
in the instrument panel. In any case, it
must never exceed 12,500 miles
(20,000 km) or 1 year
Flush and replace the engine coolant at
120 months or 150,000 miles (240,000 km)
whichever comes first.
The maximum mileage is 75,000 mi
(120,000 km). The belt must be replaced
every 5 years regardless of distance trav-
eled. The timing and accessory belts must be
changed every 37,500 miles (60,000 km) or
3 years for particularly demanding use
(dusty areas, severe weather conditions,
very low or very high temperatures for
extended periods, city driving, long periods
of idling). Under no circumstances should
these intervals be exceeded.
WARNING!
You can be badly injured working on or
around a motor vehicle. Do only service
work for which you have the knowledge
and the right equipment. If you have any
doubt about your ability to perform a
service job, take your vehicle to a compe-
tent mechanic.
Failure to properly inspect and maintain
your vehicle could result in a component
malfunction and effect vehicle handling
and performance. This could cause an
accident.
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SERVICING AND MAINTENANCE
230(Continued)
Coolant Checks
Check the engine and, intercooler (if
equipped) coolant (antifreeze) protection
every 12 months (before the onset of
freezing weather, where applicable). If the
engine and, intercooler (if equipped) is dirty
or rusty in appearance, the system should be
drained, flushed and refilled with fresh OAT
coolant (conforming to MS.90032) by an
authorized dealer. Check the front of the A/C
condenser (if equipped) or radiator for any
accumulation of bugs, leaves, etc. If dirty,
clean by gently spraying water from a garden
hose vertically down the face of the A/C
condenser (if equipped) or the back of the
radiator core.Check the engine and, intercooler (if
equipped) cooling system hoses for brittle
rubber, cracking, tears, cuts, and tightness
of the connection at the coolant recovery
bottle and radiator. Inspect the entire system
for leaks. DO NOT REMOVE THE COOLANT
PRESSURE CAP WHEN THE COOLING
SYSTEM IS HOT.
Brake System
In order to ensure brake system perfor
-
mance, all brake system components should
be inspected periodically. Refer to the
“Maintenance Plan” in this section for the
proper maintenance intervals.
Fluid Level Check — Brake Master Cylinder
The fluid level of the master cylinder should
be checked whenever the vehicle is serviced,
or immediately if the brake system warning
light is on. If necessary, add fluid to bring
level within the designated marks on the side
of the reservoir of the brake master cylinder.
Be sure to clean the top of the master
cylinder area before removing cap. With disc
brakes, fluid level can be expected to fall as
the brake pads wear. Brake fluid level should
be checked when pads are replaced. If the
brake fluid is abnormally low, check the
system for leaks.
Refer to “Fluids And Lubricants” in “Tech -
nical Specifications” for further information.When working near the radiator cooling
fan, turn the ignition to the OFF mode.
The fan is temperature controlled and
can start at any time the ignition is in the
ON mode.
WARNING! (Continued)
WARNING!
Riding the brakes can lead to brake failure
and possibly a collision. Driving with your
foot resting or riding on the brake pedal
can result in abnormally high brake
temperatures, excessive lining wear, and
possible brake damage. You would not
have your full braking capacity in an
emergency. WARNING!
Use only manufacturer's recommended
brake fluid. Refer to “Fluids And Lubri -
cants” in “Technical Specifications” for
further information. Using the wrong
type of brake fluid can severely damage
your brake system and/or impair its
performance. The proper type of brake
fluid for your vehicle is also identified on
the original factory installed hydraulic
master cylinder reservoir.
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279
Pitch & Roll
The Pitch & Roll page displays the vehicle’s
current pitch (angle up and down) and roll
(angle side to side) in degrees. The pitch and
roll gauges provide a visualization of the
current vehicle angle.Pitch & Roll Menu 2WD/4WD
Accessory Gauge
The Accessory Gauge page displays the
current status of the vehicle’s Coolant
Temperature, Oil Temperature, Oil Pressure
(Gas Vehicles Only), Transmission Tempera -
ture, and Battery Voltage.
Accessory Gauges Menu 2WD/4WD
STEERING WHEEL AUDIO
CONTROLS
The remote sound system controls are
located on the rear surface of the steering
wheel. Reach behind the wheel to access the
switches.Audio Controls (Back View Of Steering Wheel)
The right-hand control is a rocker-type
switch with a push-button in the center and
controls the volume and mode of the sound
system. Pushing the top of the rocker switch
increases the volume, and pushing the
bottom of the rocker switch decreases the
volume.
Pushing the center button mutes the radio.
1 — Current Pitch
2 — Current Roll
1 — Coolant Temperature
2 — Oil Temperature
3 — Oil Pressure (Gas Vehicles Only)
4 — Battery Voltage
5 — Transmission Temperature (Automatic
Transmissions Only)
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319
INDEX
A
Accessories ....................................... 258Mopar ........................................... 258
Active Speed Limiter .......................... 156
Adaptive Cruise Control (ACC)
(Cruise Control) ................................. 158
Adding Fuel ...................................... 169
Additives, Fuel .................................. 249
Air Bag Air Bag Operation ........................... 107Air Bag Warning Light ..................... 105
Disable, Passenger Air Bag.............. 107

Enhanced Accident Response ... 115 , 209

Event Data Recorder (EDR) ............. 209
Front Air Bag ................................. 106
If Deployment Occurs ..................... 114
Knee Impact Bolsters ..................... 112
Maintaining Your Air Bag System ..... 116
Maintenance .................................. 116
Redundant Air Bag Warning Light .... 105
Transporting Pets ........................... 134
Air Bag Light ........................65 , 105 , 136
Air Conditioning................................... 44
Air Conditioning Filter .......................... 46
Air Conditioning System ....................... 44
Air Conditioning, Operating Tips ............ 45 Air Pressure
Tires ............................................. 233
Alarm Arm The System .............................. 15
Disarm The System .......................... 15
Security Alarm ............................15 , 68
Alarm (Security Alarm) ......................... 16
Alterations/Modifications Vehicle ............................................. 2
Android Auto...................... 266 , 271 , 302
Apps ............................................. 274
Communication ............................. 273
Maps ............................................ 272
Music ........................................... 273
Antifreeze (Engine Coolant) ................ 253
Anti-Lock Brake System (ABS) .............. 78
Anti-Lock Warning Light ....................... 68
Apple CarPlay .................... 267 , 274 , 303
Apps ............................................. 276
Maps ............................................ 276
Messages ...................................... 275
Music ........................................... 275
Phone ........................................... 275
Assist, Hill Start .................................. 85
Audio Systems (Radio) ................260 , 262
Auto Down Power Windows ................... 46
Automatic Headlights .......................... 33 Automatic High Beams .........................33
Automatic Temperature Control (ATC) ....44
Automatic Transmission......................145
Fluid Level Check ................... 231 , 232
Fluid Type ............................. 231 , 257
Special Additives ............................231

Auxiliary Electrical Outlet (Power Outlet)... 56

Auxiliary Power Outlet ..........................56
Auxiliary Switches ................................58
Axle Fluid..........................................257
Axle Lock ..........................................151
B
Battery ........................................ 66 , 225
Charging System Light ......................66
Belts, Seat ........................................136
Blind Spot Monitoring ..........................87
Brake Assist System .............................79
Brake Control System ...........................79
Brake Fluid ............................... 230 , 257
Brake System ....................................230 Fluid Check ...................................230
Master Cylinder ..............................230
Warning Light...................................65
Brake/Transmission Interlock...............144
Bulb Replacement ..................... 179 , 181
Bulbs, Light .............................. 137 , 179
2020_JEEP_JL_WRANGLER_UG_RHD_UK.book Page 319