coolant temperature RAM CHASSIS CAB 2007 User Guide

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
7

Adding Coolant
Your vehicle has been built with an improved engine
coolant that allows extended maintenance intervals. This
coolant can be used up to 5 Years or 100,000 miles before
replacement. To prevent reducing this extended mainte-
nance period, it is important that you use the same
coolant throughout the life of your vehicle. Please review
these recommendations for using Hybrid Organic Addi-
tive Technology (HOAT) coolant.
When adding coolant, a minimum solution of 50% rec-
ommended Mopar Antifreeze/ Coolant 5 Year/100,000
Mile Formula HOAT (Hybrid Organic Additive Technol-
ogy), or equivalent, in water should be used. Use higher
concentrations (not to exceed 70%) if temperatures below

34°F (
37°C ) are anticipated.
Use only high purity water such as distilled or deionized
water when mixing the water/engine coolant solution. 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 coolant types will decrease the life of the
engine coolant and will require more frequent coolant
changes.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss of
coolant, and to insure that coolant will return to the
radiator from the coolant recovery bottle.
The cap should be inspected and cleaned if there is any
accumulation of foreign material on the sealing surfaces. MAINTAINING YOUR VEHICLE 429
7

The radiator normally remains completely full, so there is
no need to remove the radiator cap unless checking for
coolant freeze point or replacing 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 coolant is needed to maintain 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 (a
few kilometers) of operation, you may observe vapor
coming from the front of the engine compartment. This is
normally a result of moisture from rain, snow, or high
humidity accumulating on the radiator and being vapor-
ized when the thermostat opens, allowing hot coolant to
enter the radiator. If an examination of your engine compartment shows no
evidence of radiator or hose leaks, the vehicle may be
safely driven. The vapor will soon dissipate.
• Do not overfill the coolant recovery bottle.
• Check coolant freeze point in the radiator and in the
coolant recovery bottle. If antifreeze needs to be
added, contents of coolant recovery bottle must also be
protected against freezing.
• If frequent coolant additions are required, or if the
level in the coolant recovery bottle does not drop when
the engine cools, the cooling system should be pres-
sure tested for leaks.
• Maintain coolant concentration at 50% HOAT engine
coolant (minimum) and distilled water for proper
corrosion protection of your engine which contains
aluminum components. MAINTAINING YOUR VEHICLE 431
7

• Make sure that the radiator and coolant recovery
bottle overflow hoses are not kinked or obstructed.
• Keep the front of the radiator clean. If your vehicle is
equipped with air conditioning, keep the front of the
condenser clean, also.
• Do not change the thermostat for summer or winter
operation. If replacement is ever necessary, install
ONLY the correct type thermostat. Other designs may
result in unsatisfactory coolant performance, poor gas
mileage, and increased emissions.
Fan
Inspection
Check the fan for cracks and bent or broken blades. If any
of these conditions exist, you must replace the fan. Make
sure it is securely mounted. NOTE: This service procedure must be performed by a
trained service technician. Make arrangements with your
authorized Dodge Truck Dealer for this inspection.
Charge Air Cooler — Inter-Cooler (Diesel
Engines)
The charge air cooler is positioned between the radiator
and the air conditioner condenser. Air enters the engine
through the air cleaner and passes through the turbo-
charger where it is pressurized. This pressurized air
rapidly reaches high temperature. The air is then directed
through a hose to the charge air cooler and through
another hose to the intake manifold of the engine. The air
entering the engine has been cooled by about 50 to 100
degrees Fahrenheit. This cooling process enables more
efficient burning of fuel resulting in fewer emissions.
To guarantee optimum performance of the system, keep
the surfaces of the charge air cooler, condenser and
radiator clean and free of debris. Periodically check the432 MAINTAINING YOUR VEHICLE

Schedule “B”
Follow schedule “B” if you usually operate your vehicle
under one or more of the following conditions.
• Day or night temperatures are below 32° F (0° C).
• Stop and go driving.
• Extensive engine idling.
• Driving in dusty conditions.
• Short trips of less than 10 miles (16 km).
• More than 50% of your driving is at sustained high
speeds during hot weather, above 90° F (32° C).
• Trailer towing.
• Snowplowing.
• Heavy Loading.
• Taxi, police, or delivery service (commercial service). • Off-road or desert operation.
• If equipped for and operating with E-85 (ethanol)
fuel.
NOTE: If ANY of these apply to you then change your
engine oil every 3,000 miles (5 000 km) or 3 months,
whichever comes first and follow schedule “B” of the
 Maintenance Schedules  section of this manual.
NOTE: If ANY of these apply to you then flush and
replace your engine coolant every 102,000 miles (170 000
km) or 60 months, whichever comes first and follow
schedule “B” of the  Maintenance Schedules  section of
this manual.
NOTE: If none of these apply to you, then change your
engine oil at every interval shown on schedule  A  of the
 Maintenance Schedules  section of this manual. SCHEDULE “B” 487
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