2007 RAM CHASSIS CAB coolant temperature

If temperatures are below 32°F (0°C), operate the engine
at moderate speeds for 5 minutes before full loads are
applied.
Engine Idling — In Cold Weather
Avoid prolonged idling in ambient temperatures below
0°F. 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. Excessive idle time
can also cause damage to the engine exhaust aftertreat-
ment system.
NOTE: An optional driver-controlled high idle speed is
available on automatic transmission equipped vehicles with speed control. This feature allows the driver to
select an elevated idle speed between 1100 and 1500
rpms. Your dealer can enable this feature.
NOTE:
• If ambient temperatures are low and the coolant
temperature is below 200°F (93°C), the engine idle
speed will slowly increase to 1000 RPM after 2 minutes
of idle, if the following conditions are met:
• foot is off brake pedal and throttle pedal
• automatic transmission is in Park (P)
• vehicle speed is zero
• Applying the throttle will cancel fast idle
• If the engine is equipped with an exhaust brake,
operating the exhaust brake at idle will greatly im-
prove warm up rate and will help keep the engine
close to operating temperature during extended idle. STARTING AND OPERATING 261
5

Stopping The Engine
Idle the engine a few minutes before routine shutdown.
After full load operation, idle the engine 3 to 5 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 especially important for turbo-
charged, charge air cooled engines, like your Turbo Ram.
NOTE: During engine shut down on vehicles equipped
with manual transmissions, it is normal for the diesel
engine to resonate heavily for a moment during engine
shut off. When the engine is connected to a manual
transmission, this resonance causes load gear rattle from
the transmission. This is commonly referred to as “shut
down rattle”. The manufacturer recommends performing
engine shut down with the clutch pedal pushed to the
floor (clutch disengaged). When engine shut down is
performed in this manner the rattle is reduced (not
eliminated). Driving
Condition Load Turbo-
charger
Temperature Idle Time
(min.) Be-
fore Engine
Shutdown
Stop and
Go Empty Cool Less than
One
Stop and
Go Medium One
Highway
Speeds Medium Warm Two
City Traffic Maximum
GCWR Three
Highway
Speeds Maximum
GCWR Four
Uphill
Grade Maximum
GCWR Hot Five262 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 (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. STARTING AND OPERATING 263
5

• Up Steep Hills —
select a lower transmission gear, but try and keep the
torque converter clutch engaged.
• 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:
Idle 700 to 800 RPM ............... 10psi(69kPa)
Full speed and load .............. 30psi (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. Do Not Operate The Engine With Failed Parts
Practically all failures give some warning before the parts
fail. Be on the alert for changes in performance, 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 operating range, in
the engine operating temperature
• excessive smoke
• oil pressure drop264 STARTING AND OPERATING

Change Engine Oil (Gas Engines)
Road conditions as well as your kind of driving affect the
interval at which your oil should be changed. Check the
following to determine if any apply to you:
• Frequent short trips where the engine does not achieve
full operating temperature (operating temperature de-
fined as 190° F (66° C ) coolant temperature).
• Extensive engine idling (over 10 minutes per hour of
operation) at ambient temperatures less than 32° F (0°
C).
• Driving in dusty conditions.
• Frequent trailer towing.
• Taxi, police, or delivery service (commercial service).
• Off-road or desert operation.
• Extensive operation at high engine speeds (greater
than 2900 rpm) and loads (greater than 70% throttle). If ANY of these apply to you, then change your engine oil
at every interval shown in schedule  B  of the  Mainte-
nance Schedules  section of this manual.
If none of these apply to you, then change your engine oil
at every interval shown on schedule  A  of the  Mainte-
nance Schedules  section of this manual.
NOTE: Most vehicles are operated under the conditions
listed for Schedule  B. 
Dusty Conditions
Driving through dust-laden air increases the problems of
keeping abrasive materials out of the engine. Under these
conditions, special attention should be given to the
engine air cleaner, the crankcase inlet air cleaner and the
crankcase ventilation system. Make sure that these units
are clean at all times. This will tend to reduce to a
minimum the amount of abrasive material that may enter
the engine.400 MAINTAINING YOUR VEHICLE

Engine Oil Viscosity (SAE Grade)
Use SAE 15W-40 Engine Oil that meets
DaimlerChrysler Materials Standard MS-10902 and the
API CJ-4 engine oil category.
Engine oil not designated by the DaimlerChrysler or
Cummins Material Standards and API CJ-4 should not be
used, engine and exhaust system durability may be
compromised. For lower temperature operation SAE
5W-40 engine oils may be used. These oils must meet the
same requirements as stated previously. Your engine oil
filler cap also shows the recommended engine oil viscos-
ity for your vehicle.
Synthetic Engine Oils
You may use synthetic engine oils provided the recom-
mended oil quality requirements are met, and the recom-
mended maintenance intervals for oil and filter changes
are followed. Materials Added to Engine Oil
The manufacture strongly recommends against the addi-
tion of any additives (other than leak detection dyes or
lube odorants) to the engine oil. Engine oil is an engi-
neered product and it’s performance may be impaired by
supplemental additives.
NOTE: The manufacturer offers a lube odorant (Mopar
Diesel Fresh) for diesel engines crankcases. The lube
odorant is recommended by the manufacturer to reduce
the sulfur smell that may occur during engine idling.
Engine Oil Filter
Refer to Fluids, Lubricants and Genuine Parts for the
correct part number. The engine oil filter should be
changed at every engine oil change.
Engine Oil And Filter — Change
Operate the engine until the coolant temperature reaches
140°F (60°C). Shut the engine off. Remove the oil drain
plug. MAINTAINING YOUR VEHICLE 403
7

of the exhaust system abnormally contacts the under-
body hardware, the isolator and/or hanger should be
replaced.
Cooling System
WARNING!You or others can be badly burned by hot coolant or
steam from your radiator. If you see or hear steam
coming from under the hood, don’t open the hood
until the radiator has had time to cool. Never try to
open a cooling system pressure cap when the radia-
tor is hot. Engine Coolant Checks
Check the engine coolant (antifreeze) protection every 12
months (before the onset of freezing weather, where
applicable). If coolant is dirty or rusty in appearance, the
system should be drained, flushed and refilled with fresh
coolant. Check the front of the A/C condenser 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 coolant recovery bottle tubing for brittle rub-
ber, cracking, tears, cuts and tightness of the connection
at the bottle and radiator. Inspect the entire system for
leaks.
Extremely cold ambient temperature may require the
addition of a “winter front” for effective operation of the
cab heating/cooling system. Make certain that a percent-
age of the radiator is exposed for adequate air flow
through the charge air cooler and automatic transmission426 MAINTAINING YOUR VEHICLE

oil cooler. The percentage of opening must be increased
with the increasing ambient air temperature and/or
engine load. If the cooling fan can be heard cycling
frequently, increase the size of the opening in the winter
front.
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 — Drain, Flush and Refill
At the intervals shown on the Maintenance Schedules,
the system should be drained, flushed and refilled. MAINTAINING YOUR VEHICLE 427
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