2007 Ram 2500 (Diesel) engine overheat

CAUTION!
Do not leave your vehicle unattended with the en-
gine running as you would not be able to react to the
temperature indicator if the engine overheats.
NOTE:Engine idle speed will automatically increase to
1000 rpm at elevated coolant temperatures to improve
engine cooling.
NOTE:If the gauge pointer moves to either extreme of
the gauge, the “Check Gages” indicator will illuminate
and a single chime will sound.
14. Security Light
The light will flash rapidly for approximately 16 seconds
when the vehicle theft alarm is arming. The light will
flash at a slower rate after the alarm is set. The security
light will also come on for about two seconds when the
ignition is first turned ON.15. Transmission Range Indicator (Automatic
Transmissions Only)
When the gear selector lever is moved on vehicles with
the 48RE transmission, this indicator shows the auto-
matic transmission gear range selected (PRND21).
When the gear selector lever is moved on vehicles with
the 68RFE transmission, this indicator shows the auto-
matic transmission gear range selected (P R N D). Ve-
hicles equipped with Auto-6/Electronic Range Select
(ERS) will display the selection of the desired top gear, in
the position next to the D (Drive).
16. Odometer/Trip Odometer
The odometer shows the total distance the vehicle has
been driven.
If the odometer reading is changed during repair or
replacement, be sure to keep a record of the reading
before and after the service so that the correct mileage can
be determined.
UNDERSTANDING YOUR INSTRUMENT PANEL 201
4

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.
When using the air conditioner in extremely heavy traffic
in hot weather especially when towing a trailer, addi-
tional engine cooling may be required. If this situation is
encountered, operate the transmission in a lower gear to
increase engine RPM, coolant flow and fan speed. When
stopped in heavy traffic, it may be necessary to shift into
NEUTRAL and depress the accelerator slightly for fast
idle operation to increase coolant flow and fan speed.NOTE:On models equipped with Diesel engines, the
idle speed will automatically increase to 1000 rpm at
elevated coolant temperatures to improve engine cooling.
Your air conditioning system is also equipped with an
automatic recirculation system. When the system senses
a heavy load or high heat conditions, it may use partial
Recirculation A/C mode to provide additional comfort.
Winter Operation
When operating the system during the winter months,
make sure the air intake, located directly in front of the
windshield, is free of ice, slush, snow, or other obstruc-
tions.
268 UNDERSTANDING YOUR INSTRUMENT PANEL

STARTING PROCEDURES – DIESEL ENGINES
Before starting your vehicle, adjust your seat, adjust both
inside and outside mirrors, and fasten your seat belts.
The starter should not be operated for more than 15-
second intervals. Waiting a few minutes between such
intervals will protect the starter from overheating.
WARNING!
Be sure to turn off the engine and remove the key
from the ignition switch if you want to rest or sleep
in your car. Accidents can be caused by inadvertently
moving the gear selection lever or by pressing the
accelerator pedal. This may cause excessive heat in
the exhaust system, resulting in overheating and
vehicle fire which may cause serious or fatal injuries.
WARNING!
Do not leave children or animals inside parked
vehicles in hot weather. Interior heat build up may
cause serious injury or death.
Manual Transmission – If Equipped
Apply the parking brake, place the gearshift control lever
in NEUTRAL and depress the clutch pedal to the floor
before starting the vehicle. This vehicle is equipped with
a clutch interlocking ignition system. It will not start
unless the clutch is fully depressed.
STARTING AND OPERATING 275
5

Engine Speed Control
CAUTION!
Prevent overspeeding the engine going down hill.
When descending steep grades, use a combination of
gears and service brakes to control vehicle/engine
speed. Overspeed can cause severe engine damage.
Operating Precautions
Avoid Overheating The Engine
The temperature of the coolant (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 16 psi (110 kPa) radiator cap.
Usually the coolant temperature indicated during opera-
tion will be to the left of center in the normal range of the
gauge.
Avoid Low Coolant Temperature Operation
Continual operation at low coolant temperature below
the normal range on the gauge (140°F/60°C) can be
harmful to the engine. Low coolant 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 — Automatic Transmission
To reduce potential for engine and transmission over-
heating in high ambient temperature conditions, take the
following actions:
•City Driving —
when stopped, put transmission in neutral and increase
engine idle speed.
•Highway Driving —
reduce your speed.
288 STARTING AND OPERATING

When To Use “TOW HAUL” and “O/D OFF”
Modes
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the “TOW HAUL O/D OFF” button once to
select TOW HAUL. This will improve performance andreduce the potential for transmission overheating or
failure due to excessive shifting. When operating in
“TOW HAUL” mode, 5th gear (if equipped) is disabled
and 2-3 and 3-4 shift patterns are modified. Shifts into
Overdrive (4th gear) are allowed during steady cruise
(for improved fuel economy) and automatic closed-
throttle downshifts to 3rd gear (for improved braking)
will occur during steady braking. Pressing the “TOW
HAUL O/D OFF” button a second time to select O/D
OFF will disable 4th and 5th gear completely, which
should eliminate any excessive transmission shifting.
The “TOW HAUL” or “O/D OFF” light will illuminate in
the instrument cluster to indicate when the switch has
been activated. Pressing the switch a third time restores
normal operation. If the “TOW HAUL” or “O/D OFF”
modes are desired, the button must be pressed each time
the engine is started.
Tow Haul O/D Off Switch
STARTING AND OPERATING 301
5

When To Lock Out Overdrive
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent 4–3–4 transmission shifting
occurs, press the “TOW/HAUL” button. This will im-
prove performance and reduce the potential for transmis-
sion overheating or failure due to excessive shifting.
Torque Converter Clutch
A feature, designed to improve fuel economy, has been
included in the automatic transmission on your vehicle.
A clutch within the torque converter engages automati-
cally at calibrated speeds. This may result in a slightly
different feeling or response during normal operation in
high gear. When the vehicle speed drops or during
acceleration when the transmission downshifts to second
gear, the clutch automatically disengages.
NOTE:The torque converter clutch will not engage
until the transmission fluid and engine coolant are warm
[usually after 1-3 miles (1.6 - 4.8 km) of driving]. Becausethe engine speed is higher when the torque converter
clutch is not engaged, it may seem as if the transmission
is not shifting into Overdrive when cold. This is normal.
Pressing the “TOW/HAUL” button, when the transmis-
sion is sufficiently warm, will demonstrate that the
transmission is able to shift into and out of overdrive.
NOTE:If the vehicle has not been driven in several
days, the first few seconds of operation after shifting the
transmission into gear may seem sluggish. This is due to
the fluid partially draining from the torque converter into
the transmission. This condition is normal and will not
cause damage to the transmission. The torque converter
will refill within five seconds of shifting from Park into
any other gear position.
Out of Park Sense Alarm
Vehicles with a Diesel Engine and an Automatic Trans-
mission are equipped with an Alarm that warns the
302 STARTING AND OPERATING

Towing Tips
Before setting out on a trip, practice turning, stopping
and backing the trailer in an area away from heavy
traffic.
If using a manual transmission vehicle for trailer towing,
all starts must be in FIRST gear to avoid excessive clutch
slippage.
Towing Tips — Automatic Transmission
The “D” range can be selected when towing. However, if
frequent shifting occurs while in this range, the “TOW
HAUL” or “OD/OFF” range should be selected.
NOTE:Using the “TOW HAUL” or “OD/OFF” range
while operating the vehicle under heavy operating con-
ditions will improve performance and extend transmis-
sion life by reducing excessive shifting and heat build up.
This action will also provide better engine braking.The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See Schedule “B” in
section 8 of this manual for transmission fluid change
intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips — Tow/Haul (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the “TOW HAUL OD/OFF” feature ON when
driving in hilly areas or shift the transmission to Drive
position 2 on more severe grades.
370 STARTING AND OPERATING

NOTE:During snowplow usage on vehicles equipped
with an overhead console module, the outside tempera-
ture display will show higher temperatures than the
outside ambient temperature. The higher displayed tem-
perature is due to blocked or reduced airflow to the
underhood ambient temperature sensor by the snow-
plow. This is common and outside temperature display
operation will return to normal when the snowplow is
removed.
General Maintenance
Snowplows should be maintained in accordance with the
plow manufacturer’s instructions.
Keep all snowplow electrical connections and battery
terminals clean and free of corrosion.When plowing snow, to avoid transmission and driv-
etrain damage, the following precautions should be ob-
served.
•Operate with transfer case in 4L when plowing small
or congested areas where speeds are not likely to
exceed 15 mph (24 km/h). At higher speeds operate in
4H.
•Vehicles with 48RE transmissions should use 4L range
when plowing deep or heavy snow for extended
periods of time to avoid transmission overheating.
•Do not shift the transmission unless the engine has
returned to idle and wheels have stopped. Make a
practice of stepping on the brake pedal before shifting
the transmission.
376 STARTING AND OPERATING