2008 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.
²Highway Driving Ð
reduce your speed.
STARTING AND OPERATING 281
5

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 radiator
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 anyaccumulation 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 temperatures 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.
436 MAINTAINING YOUR VEHICLE

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
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 (160
000 km) before replacement. To prevent reducing this
extended maintenance period, it is important that you
use the same coolant throughout the life of your vehicle.
Please review these recommendations for using Hybrid
Organic Additive Technology (HOAT) coolant. When
adding coolant:
²The manufacturer recommends using Mopart
Antifreeze/Coolant 5 Year/100,000 Mile Formula
HOAT (Hybrid Organic Additive Technology).
²Mix a minimum solution of 50% HOAT engine coolant
and distilled water. Use higher concentrations (not to
exceed 70%) if temperatures below -34ÉF (-37ÉC) are
anticipated.
²Use only high purity water such as distilled or deion-
ized 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 ensure that coolant will return to the radiator from
the coolant recovery bottle.
MAINTAINING YOUR VEHICLE 439
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.
²Do not overfill the coolant recovery bottle.
²Check 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.
²If 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.
²Maintain 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 441
7

Radiator (Coolant Pressure)............... 439
Car Washes............................ 455
Carbon Monoxide Warning...............76,181
Cargo Light............................ 133
Cassette Tape and Player Maintenance......... 247
Catalyst Full Message..................... 425
CD (Compact Disc) Player............202,210,224
Cellular Phone.......................... 89
Center High Mounted Stop Light............ 473
Center Lap Belts......................... 45
Center Seat Storage Compartment.........167,168
Certification Label....................... 352
Charge Air Cooler....................... 442
Chart, Tire Sizing........................ 317
Check Engine Light (Malfunction Indicator
Light)................................ 194
Child Restraint........................61,62
Child Restraint Tether Anchors.............65,69
Child Seat............................62,68Cigar Lighter........................... 162
Cleaning
Wheels............................. 457
Climate Control......................... 249
Clock.....................200,204,212,225,239
Closed Crankcase Ventilation (CCV) Filter...... 426
Clutch Linkage Maintenance................ 445
Compact Disc (CD) Maintenance............. 248
Compact Spare Tire...................... 328
Compass Calibration..................... 150
Compass Variance....................... 150
Console, Overhead....................... 142
Contract, Service........................ 499
Coolant Pressure Cap (Radiator Cap).......... 439
Cooling System......................... 436
Adding Coolant (Antifreeze).............. 439
Coolant Capacity...................... 479
Coolant Level...................436,437,440
Disposal of Used Coolant................ 440
508 INDEX

Drain, Flush, and Refill.................. 437
Inspection........................... 440
Points to Remember.................... 441
Pressure Cap......................... 439
Radiator Cap......................... 439
Selection of Coolant (Antifreeze).........438,480
Temperature Gauge..................... 191
Cruise Control (Speed Control).............. 139
Cup Holder............................ 163
Customer Assistance..................... 497
Data Recorder, Event...................... 59
Daytime Running Lights................... 132
Dealer Service.......................... 410
Defroster, Rear Window.................87,173
Defroster, Windshield................77,251,253
Delay (Intermittent) Wipers................. 136
Diesel Exhaust Brake..................... 283
Diesel Fuel............................ 348Diesel Fuel Requirements.................. 348
Differential, Limited-Slip.................. 306
Dipsticks.............................. 413
Power Steering........................ 431
Disc Brakes............................ 443
Disposal.............................. 418
Engine Oil........................... 418
Used Coolant (Antifreeze)................ 440
Door Locks............................. 26
Door Locks, Automatic.................... 146
Door Opener, Garage..................... 151
Draining Fuel/Water Separator Filter.......... 422
Drive Belts............................ 418
Driving
Through Flowing, Rising, or Shallow Standing
Water.............................. 307
Dual Rear Wheels.....................337,394
DVD Player (Video Entertainment System)...... 241
INDEX 509
10

Placard, Tire and Loading Information......... 320
Power
Distribution Center (Fuses)............... 459
Door Locks........................... 27
Mirrors.............................. 86
Outlet (Auxiliary Electrical Outlet).......... 160
Seats............................... 119
Sliding Rear Window.................34,173
Steering..........................315,431
Sunroof............................. 158
Windows............................. 32
Power Steering Fluid..................... 482
Pregnant Women and Seat Belts.............. 47
Pretensioners
Seat Belts............................. 45
Programmable Electronic Features............ 146
Radial Ply Tires......................... 327
Radiator Cap (Coolant Pressure Cap).......... 439Radio Broadcast Signals................... 200
Radio, Navigation....................... 238
Radio Operation...................202,210,224
Radio Remote Controls.................... 246
Radio, Satellite.......................239,241
Radio (Sound Systems)..............202,210,224
Rear Axle (Differential).................... 446
Rear Seat, Folding....................121,123
Rear Wheel Bearings..................... 451
Rear Window Features.................... 173
Rear Window, Sliding...................34,174
Reclining Front Seats..................... 117
Reclining Rear Seats...................... 121
Recorder, Event Data...................... 59
Recreational Towing...................... 375
Shifting into Transfer Case Neutral (N)....376,378
Shifting out of Transfer Case Neutral (N) . . . 377,380
Refrigerant............................ 431
Reminder, Seat Belt....................... 46
INDEX 517
10