2008 DODGE 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 ªCheck Gaugesº indicator will illuminate
and a single chime will sound.
13. Security Light
The light will flash rapidly for approximately 16 seconds
when the Vehicle Theft Alarm is arming. The light willflash 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.
14. Transmission Range Indicator (Automatic
Transmissions Only)
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).
15. Odometer/Trip Odometer
The odometer shows the total distance the vehicle has
been driven. U.S. federal regulations require that upon
transfer of vehicle ownership, the seller certify to the
purchaser the correct mileage that the vehicle has been
driven. Therefore, if the odometer reading is changed
192 UNDERSTANDING YOUR INSTRUMENT PANEL

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. For proper coolant type,
refer to ªRecommended Fluids and Genuine Partsº in
Section 7.
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.
UNDERSTANDING YOUR INSTRUMENT PANEL 261
4

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 vehicle. Accidents can be caused by inadvert-
ently moving the shift 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.
Automatic Transmission ± If Equipped
Start the engine with the shift lever in NEUTRAL or
PARK position. Apply the brake before shifting to any
driving range.
The CumminstDiesel engine is equipped with several
features designed to assist cold weather starting and
operation:
²The 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.
268 STARTING AND OPERATING

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 (240ÉF/116ÉC)
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 (140ÉF/60ÉC) 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 Ð Automatic Transmission
To reduce potential for engine and transmission over-
heating in high ambient temperature conditions, take the
following actions:
²City Driving Ð
when stopped, put transmission in neutral and increase
engine idle speed.
²Highway Driving Ð
reduce your speed.
STARTING AND OPERATING 281
5

The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See Maintenance
Schedule in section 8 of this manual for transmission
fluid change intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips Ð Tow/Haul (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the ªTOW HAULº feature ON when driving in
hilly areas or downshift the transmission (using the
Auto-6 [ERS] switch).
Towing Tips Ð Electronic Speed Control (If
Equipped)
þ
Don't use in hilly terrain or with heavy loads.
þWhen using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
þUse speed control in flat terrain and with light loads to
maximize fuel efficiency.
Towing Tips Ð Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
þCity Driving
When stopped for short periods of time, put transmission
in neutral and increase engine idle speed.
þHighway Driving
Reduce speed.
þAir Conditioning
Turn off temporarily.
STARTING AND OPERATING 369
5

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.
²Operate 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.
²Vehicles with 68RFE transmissions should use 4L
range when plowing deep or heavy snow for extended
periods of time to avoid transmission overheating.
²Do 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.
374 STARTING AND OPERATING

In general, the least amount of accelerator pedal pressure
to maintain the rocking motion without spinning the
wheels or racing the engine, is most effective. Racing the
engine or spinning the wheels, due to the frustration of
not freeing the vehicle, may lead to transmission over-
heating and failure. Allow the engine to idle with the
transmission selector in NEUTRAL for at least one
minute after every five rocking-motion cycles. This will
minimize overheating and reduce the risk of transmis-
sion failure during prolonged efforts to free a stuck
vehicle.
EMERGENCY TOW HOOKS Ð IF EQUIPPED
Your vehicle may be equipped with emergency tow
hooks.NOTE:For off-road recovery, it is recommended to use
both of the front tow hooks to minimize the risk of
damage to the vehicle.
WARNING!
Chains are not recommended for freeing a stuck
vehicle. Chains may break, causing serious injury or
death.
WARNING!
Stand clear of vehicles when pulling with tow hooks.
Tow straps and chains may break, causing serious
injury.
WHAT TO DO IN EMERGENCIES 401
6

Coolant bottle level check
The coolant reserve system provides a quick visual
method of determining that the coolant level is adequate.
With the engine idling and warmed to the normal
operating temperature, the level of the coolant on the
coolant bottle should be between the fluid level marks.
Check the coolant level whenever the hood is raised.
The radiator normally remains completely full, so there is
no longer a need to remove the coolant pressure cap
except for checking coolant freeze point or replacement
with new antifreeze coolant.WARNING!
Never add coolant to the radiator when the engine is
overheated. Do not loosen or remove pressure cap to
cool overheated engine! The coolant is under pres-
sure and severe scalding could result.
Cooling System Ð Drain, Flush and Refill
At the intervals shown on the Maintenance Schedules,
the system should be drained, flushed and refilled. See
you authorized dealer for service.
MAINTAINING YOUR VEHICLE 437
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