2004 DODGE RAM 2500 DIESEL radiator cap

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.
NOTE:The engine speed will automatically increase to
1000 RPM at elevated coolant temperature to improve
engine cooling.
216 STARTING AND OPERATING

Cooling System
Cooling System Maintenance
At the intervals shown in the Maintenance Schedules
Section of the manual, the system should be drained,
flushed and filled.
Inspection
Coolant protection checks should be made every 12
months (prior to 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 as specified.
Inspect the entire cooling system for leaks. Check the face
of the radiator for any accumulation of bugs, leaves, or
other foreign matter. If dirty, clean the radiator core with
a garden hose. With the engine OFF, gently spray water
from the back of the radiator core. Check coolant bottle
tube for condition and tightness of connections at coolant
bottle and radiator.Check the coolant pressure cap and coolant bottle for
proper vacuum sealing. With the engine at normal oper-
ating temperature, note the level of the coolant in the
coolant bottle. Without removing the pressure cap (with
the engine off), drain a small amount of coolant from the
radiator drain cock. If the coolant level in the coolant
bottle drops, the system is sealing properly.
Extremely cold ambient temperature may require the
addition of a ªwinter frontº 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 transmission
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.
MAINTAINING YOUR VEHICLE 343
7

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.
Drain, Flush And Refill
At intervals shown on the Maintenance Schedules, the
system should be drained, flushed and refilled. Refer to
your dealer or consult a service manual for proper
procedures.
Adding Coolant
When adding coolant or refilling system, a 50% solution
of ethylene glycol antifreeze coolant in water should be
used. Higher concentrations (not to exceed 65%) are
required if temperatures below -34 ÉF (-37 ÉC) are antici-
pated. Use only high purity water such as distilled or
deionized water when mixing the water/antifreeze 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
maintain the proper level of protection against freezing
according to the temperatures occurring in the area
where the vehicle is operated.
344 MAINTAINING YOUR VEHICLE

NOTE:Mixing coolant types will decrease the life of the
engine coolant and will require more frequent coolant
changes.
When additional coolant is needed to maintain the
proper level, add the recommended concentration of
antifreeze and water to the overflow bottle. Do not
overfill.
NOTE:Failure to follow the antifreeze concentration
and replacement recommendations, or failure to use
antifreeze formulated to prevent corrosion of all cooling
system metals, may result in radiator plugging, overheat-
ing, or cooling system leaks such as in core hole plugs.WARNING!
Never add coolant to the radiator when the engine is
overheated. Do not loosen or remove pressure cap to
cool an overheated engine. The coolant is under
pressure and severe scalding could result.
Recommended Engine Coolant
Refer to Recommended Fluids, Lubricants and Genuine
Parts for the correct Fluid type.
MAINTAINING YOUR VEHICLE 345
7

CAUTION!
Mixing of coolants other than specified (HOAT),
may result in engine damage that may not be cov-
ered under the new vehicle warranty, and decreased
corrosion protection. If a non-HOAT coolant is intro-
duced into the cooling system in an emergency, it
should be replaced with the specified coolant as
soon as possible.
Do not use plain water alone or alcohol base anti-
freeze products. Do not use additional rust inhibi-
tors or antirust products, as they may not be compat-
ible with the radiator coolant and may plug the
radiator.
This vehicle has not been designed for use with
Propylene Glycol based coolants. Use of Propylene
Glycol based coolants is not recommended.
Disposal Of Used Engine Coolant
Used ethylene glycol based engine coolant is a regulated
substance requiring proper disposal. Check with your
local authorities to determine the disposal rules for your
community. Do not store ethylene glycol-based engine
coolant in open containers or allow it to remain in
puddles on the ground. Prevent ingestion by animals and
children. If ingested by a child, contact a physician
immediately. Clean up any ground spills immediately.
Coolant Pressure Cap
The coolant pressure cap must be fully tightened to
prevent loss of coolant and to insure that coolant will
return to the radiator from the coolant reserve tank.
346 MAINTAINING YOUR VEHICLE

WARNING!
Never add coolant when the engine is overheated.
Do not loosen or remove the pressure cap to cool an
overheated engine. Heat causes pressure 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.
CAUTION!
Recheck the cooling system to insure total system is
full of coolant.
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)
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
MAINTAINING YOUR VEHICLE 347
7

Child Seat............................56,62
Cigar Lighter........................... 127
Climate Control......................... 185
Clock................................ 151
Clutch Linkage Maintenance................ 350
Compact Disc Maintenance................. 184
Compact Disc Player..................158,164
Compact Spare Tire...................... 255
Compass.............................. 117
Compass Calibration..................... 117
Compass Variance....................... 118
Computer, Trip/Travel.................... 113
Console, Overhead....................... 112
Contract, Service........................ 404
Cooling System......................... 343
Coolant Capacity...................... 379
Coolant Level......................... 344
Disposal of Used Coolant................ 346
Drain, Flush, and Refill.................. 344Inspection........................... 343
Radiator Cap......................343,346
Selection of Coolant..................345,380
Temperature Gauge..................... 146
Cruise Control.......................... 109
Cup Holder............................ 128
Customer Assistance..................... 402
Daytime Running Lights................... 102
Dealer Service.......................... 322
Defroster, Rear Window..............78,191,195
Defroster, Windshield..................186,189
Delay Wipers........................... 105
Differential, Limited-Slip.................. 237
Dipsticks.............................. 325
Power Steering........................ 339
Disc Brakes............................ 348
Disposal.............................. 331
Engine Oil........................... 331
414 INDEX

Passing Light........................... 104
Pedals, Adjustable....................... 108
Phone, Cellular.......................... 79
Phone, Hands-Free....................... 79
Pickup Box............................ 133
Placard, Tire and Loading Information......... 247
Power
Distribution Center..................... 366
Door Locks........................... 17
Mirrors.............................. 77
Outlet.............................. 126
Seats................................ 95
Steering..........................242,339
Windows............................. 31
Power Steering Fluid..................... 381
Pregnant Women and Seat Belts.............. 44
Pretensioners
Seat Belts............................. 42
Programmable Electronic Features.........121,125Programming Transmitters..............121,125
Radial Ply Tires......................... 255
Radiator Cap........................... 343
Radio........................152,158,168,175
Radio Operation......................152,168
Radio Remote Controls.................... 181
Rear Axle............................. 351
Rear Wheel Bearings..................... 356
Reclining Front Seats...................... 93
Recommended Fluids, Lubricants and Genuine
Parts............................... 380
Recreational Towing...................... 286
Shifting into Transfer Case Neutral (N)....286,288
Shifting out of Transfer Case Neutral (N) . . . 287,290
Refrigerant............................ 339
Relays and Flashers...................... 366
Reminder, Seat Belt....................... 43
Remote Keyless Entry..................... 22
INDEX 421
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