2007 JEEP GRAND CHEROKEE coolant temperature

CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warnings have been established for the tire size
equipped on your vehicle. Undesirable system op-
eration or sensor damage may result when using
replacement equipment that is not of the same size,
type, and/or style. After-market wheels can cause
sensor damage. Do not use tire sealant from a can, or
balance beads if your vehicle is equipped with a
TPMS, as damage to the sensors may result.
13. Temperature Gauge
The temperature gauge shows engine coolant tempera-
ture. Any reading within the normal range indicates that
the engine cooling system is operating satisfactorily.The gauge pointer will likely indicate a higher tempera-
ture when driving in hot weather, up mountain grades,
or when towing a trailer. It should not be allowed to
exceed the upper limits of the normal operating range.
CAUTION!
Driving with a hot engine cooling system could
damage your vehicle. If temperature gauge reads (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
the “H”, and you hear continuous chimes, turn the
engine off immediately, and call for service.
UNDERSTANDING YOUR INSTRUMENT PANEL 179
4

NOTE:Extended use of recirculation may cause the
windows to fog. If the interior of the windows begins to
fog, press the “Recirculate” icon button to return to
outside air. Some temp./humidity conditions will cause
captured interior air to condense on windows and ham-
per visibility. For this reason, the system will not allow
“Recirculate” to be selected while in the defrost or
defrost/floor modes. Attempting to use the recirculation
while in these modes will cause the LED in the button to
blink and then turn off.
Operating Tips
Window Fogging
Windows will fog on the inside when the humidity inside
the vehicle is high. This often occurs in mild or cool
temperatures when it’s rainy or humid. In most cases
turning on the Air-conditioning (pressing the snowflake
button) will clear the fog. Adjust the temperature control,
air direction and blower speed to maintain comfort.As the temperature gets colder it may be necessary to
direct air onto the windshield. Adjust the temperature
control and blower speed to maintain comfort. Higher
blower speeds will reduce fogging. Interior fogging on
the windshield can be quickly removed by selecting the
defrost mode.
Regular cleaning of the inside of the windows with a
non-filming cleaning solution (vinegar and water works
very well) will help prevent contaminates (cigarette
smoke, perfumes, etc.) from sticking to the windows.
Contaminates increase the rate of window fogging.
Summer Operation
Air conditioned vehicles must be protected with a high
quality antifreeze coolant during summer to provide
proper corrosion protection and to raise the boiling point
of the coolant for protection against overheating. A 50 %
concentration is recommended. Refer to Recommended
Fluids and Genuine Parts for the proper coolant type.
242 UNDERSTANDING YOUR INSTRUMENT PANEL

ENGINE BLOCK HEATER — IF EQUIPPED
The engine block heater warms engine coolant and per-
mits quicker starts in cold weather. Connect the cord to a
standard 110-115 volt AC electrical outlet with grounded,
three wire extension cord.
Use the heater when temperatures below 0°F (-18°C) are
expected to last for several days.
The engine block heater cord is located:
•3.7L/4.7L Engine — coiled and strapped to the engine
oil dipstick tube.
•5.7L Engine — bundled and fastened to the injector
harness.
WARNING!
Remember to disconnect the cord before driving.
Damage to the 110-115 volt AC electrical cord could
cause electrocution.
AUTOMATIC TRANSMISSION
CAUTION!
Damage to the transmission may occur if the follow-
ing precautions are not observed:
•Shift into P (Park) only after the vehicle has come
to a complete stop.
•Shift into or out of R (Reverse) only after the
vehicle has come to a complete stop and the
engine is at idle speed.
•Do not shift from R (Reverse), P (Park), or N
(Neutral) into any forward gear when the engine
is above idle speed.
•Before shifting into any gear, make sure your foot
is firmly on the brake pedal.
STARTING AND OPERATING 253
5

Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (5th gear for 3.7L engine, 4th and
5th gears for 4.7L and 5.7L engines). The transmission
will automatically shift from direct gear to Overdrive if
the following conditions are present:
•the transmission selector is in D (Drive);
•the engine coolant has reached normal operating tem-
perature;
•vehicle speed is above approximately 30 mph (48
km/h);
•the “TOW/HAUL” button has not been activated;
•transmission has reached normal operating tempera-
ture.
NOTE:If the vehicle is started in extremely cold tem-
peratures, the transmission may not shift into Overdriveand will automatically select the most desirable gear for
operation at this temperature. Normal operation will
resume when the transmission fluid temperature has
risen to a suitable level. Refer also to the Note under
torque converter clutch, later in this section.
During cold temperature operation you may notice de-
layed upshifts depending on engine and transmission
temperature. This feature improves the warm up time of
the engine and transmission.
If the transmission temperature gets extremely hot, the
transmission will automatically select the most desirable
gear for operation at this temperature. If the transmission
temperature becomes hot enough, the “TRANSMISSION
OVER TEMP” message may display and the transmis-
sion may downshift out of Overdrive until the transmis-
sion cools down. After cool down, the transmission will
resume normal operation.
258 STARTING AND OPERATING

for any accumulation of bugs, leaves, etc. If dirty, clean by
gently spraying water from a garden hose vertically
down the face of the condenser.
Check the engine 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.
With the engine at normal operating temperature (but
not running), check the cooling system pressure cap for
proper vacuum sealing by draining a small amount of
coolant from the radiator drain cock. If the cap is sealing
properly, the antifreeze/coolant will begin to drain from
the coolant recovery bottle. DO NOT REMOVE THE
COOLANT PRESSURE CAP WHEN THE COOLING
SYSTEM IS HOT.Cooling System — Drain, Flush, And Refill
At the intervals shown in the appropriate “Maintenance
Schedule,” the system should be drained, flushed, and
refilled.
If the solution is dirty and contains a considerable
amount of sediment, clean and flush with reliable cooling
system cleaner. Follow with a thorough rinsing to remove
all deposits and chemicals. Properly dispose of old
antifreeze/coolant solution.
Selection Of Coolant
Use only the manufacturer’s recommended antifreeze/
coolant, refer to Fluids, Lubricants, and Genuine Parts for
correct antifreeze/coolant type.
MAINTAINING YOUR VEHICLE 377
7

CAUTION!
Mixing of antifreeze/coolant other than the specified
HOAT antifreeze/coolant may result in decreased
corrosion protection and engine damage. If a non-
HOAT antifreeze/coolant is introduced into the cool-
ing system in an emergency, it should be replaced
with the specified antifreeze/coolant as soon as pos-
sible.
Do not use plain water alone or alcohol base
antifreeze/coolant products. Do not use additional
rust inhibitors or antirust products, as they may not
be compatible with the antifreeze/coolant and may
plug the radiator.
This vehicle has not been designed for use with
Propylene Glycol based antifreeze/coolant. Use of
Propylene Glycol base antifreeze/coolant is not rec-
ommended.
Adding Coolant
Your vehicle has been built with an improved antifreeze/
coolant that allows extended maintenance intervals. This
antifreeze/coolant can be used up to 5 Years or 100,000
miles before replacement. To prevent reducing this ex-
tended maintenance period, it is important that you use
the same antifreeze/coolant throughout the life of your
vehicle. Please review these recommendations for using
Hybrid Organic Additive Technology (HOAT)
antifreeze/coolant.
When adding antifreeze/coolant, a minimum solution of
50% recommended MoparAntifreeze/ Coolant 5 Year/
100,000 Mile Formula HOAT (Hybrid Organic Additive
Technology), or equivalent, in water should be used. Use
higher concentrations (not to exceed 70%) if temperatures
below -34°F (-37°C) are anticipated.
378 MAINTAINING YOUR VEHICLE

Use only high purity water such as distilled or deionized
water when mixing the water/antifreeze (coolant) solu-
tion. The use of lower quality water will reduce the
amount of corrosion protection in the engine cooling
system.
Please note that it is the owner’s responsibility to main-
tain the proper level of protection against freezing ac-
cording to the temperatures occurring in the area where
the vehicle is operated.
NOTE:Mixing antifreeze/coolant types will decrease
the life of the antifreeze/coolant and will require more
frequent antifreeze/coolant changes.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss of
antifreeze/coolant, and to insure that antifreeze/coolant
will return to the radiator from the coolant recovery tank.The cap should be inspected and cleaned if there is any
accumulation of foreign material on the sealing surfaces.
WARNING!
•The warning words DO NOT OPEN HOT on the
cooling system pressure cap are a safety precau-
tion. Never add antifreeze/coolant when the en-
gine is overheated. Do not loosen or remove the
cap to cool an overheated engine. Heat causes
pressure to build up in the cooling system. To
prevent scalding or injury, do not remove the
pressure cap while the system is hot or under
pressure.
•Do not use a pressure cap other than the one
specified for your vehicle. Personal injury or
engine damage may result.
MAINTAINING YOUR VEHICLE 379
7

Disposal of Used Engine Coolant
Used ethylene glycol-based antifreeze/coolant is a regu-
lated substance requiring proper disposal. Check with
your local authorities to determine the disposal rules for
your community. To prevent ingestion by animals and
children, do not store ethylene glycol-based antifreeze/
coolant in open containers or allow it to remain in
puddles on the ground. If ingested by a child, contact a
physician immediately. Clean up any ground spills im-
mediately.
Coolant Level
The coolant bottle provides a quick visual method for
determining that the antifreeze/coolant level is adequate.
With the engine idling, and warm to normal operating
temperature, the level of the antifreeze/coolant in the
bottle should be between the ranges indicated on the
bottle.The radiator normally remains completely full, so there is
not need to remove the radiator cap unless checking for
antifreeze/coolant freeze point or replacing antifreeze/
coolant. Advise your service attendant of this. As long as
the engine operating temperature is satisfactory, the
coolant bottle need only be checked once a month.
When additional antifreeze/coolant is needed to main-
tain the proper level, it should be added to the coolant
bottle. Do not overfill.
Points To Remember
NOTE:When the vehicle is stopped after a few miles
(kilometers) of operation, you may observe vapor coming
from the front of the engine compartment. This is nor-
mally a result of moisture from rain, snow, or high
humidity accumulating on the radiator and being vapor-
ized when the thermostat opens, allowing hot antifreeze/
coolant to enter the radiator.
380 MAINTAINING YOUR VEHICLE