2007 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 (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.
288 STARTING AND OPERATING

WARNING!
Exhaust gases can injure or kill. They contain carbon
monoxide (CO) which is colorless and odorless.
Breathing it can make you unconscious and can
eventually poison you. To avoid breathing CO, fol-
low the preceding safety tips.
Exhaust System Rubber Isolator and Loop-Type
Hanger — If Equipped
Inspect surfaces whenever the vehicle is hoisted for
rubber to metal separation or deep cracks. If, however,
excessively deep localized cracks are present, or any part
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 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 any
444 MAINTAINING YOUR VEHICLE

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 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.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.
MAINTAINING YOUR VEHICLE 445
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 447
7

WARNING!
•The warning words “DO NOT OPEN HOT” on
the cooling system pressure cap are a safety pre-
caution. Never add coolant when the engine is
overheated. Do not loosen or remove the cap to
cool an overheated engine. Heat causes pressure to
build up in the cooling system. To prevent scald-
ing or injury, do not remove the pressure cap while
the system is hot or under pressure.
•Do not use a pressure cap other than the one
specified for your vehicle. Personal injury or en-
gine damage may result.
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 yourcommunity. 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 Level
The coolant bottle provides a quick visual method for
determining that the coolant level is adequate. With the
engine cold, the level of the coolant in the coolant
recovery bottle should be between the ranges indicated
on the bottle.
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.
448 MAINTAINING YOUR VEHICLE

Shifting ..........................291,297
Special Additives...................... 458
Autostick............................. 201
AxleFluid ..........................454,491
Axle Lubrication (Axle Fluid)............... 454
BallJoints ............................. 440
Battery............................... 437
Blanket..........................285,438
Emergency Starting..................... 399
Keyless Transmitter Replacement (RKE)....... 24
Saving Feature (Protection)............... 130
Bearings.............................. 458
Belts,Drive ............................ 422
Belts, Seat.............................. 34
Body Mechanism Lubrication............... 441
B-Pillar Location........................ 330
Brake Fluid............................ 491
Brake System........................321,451Anti-Lock (ABS)....................... 322
Disc Brakes.......................... 451
Fluid Check.......................... 452
Hoses.............................. 453
Master Cylinder....................... 452
Parking............................. 320
Warning Light........................ 203
Bulb Replacement....................... 474
Bulbs,Light ............................ 473
Cab Top Clearance Lights.................. 482
Calibration, Compass..................147,158
Camper............................... 188
Capacities, Antifreeze (Engine Coolant)........ 487
Capacities, Fluid........................ 487
Caps, Filler
Oil (Engine).......................... 418
Power Steering........................ 439
Radiator (Coolant Pressure)............... 447
INDEX 535
10

Car Washes............................ 463
Carbon Monoxide Warning............... 76,190
CargoLight ............................ 132
Cassette Tape and Player Maintenance......... 255
Catalyst Full Message..................... 434
CD (Compact Disc) Player............209,217,231
Cellular Phone.......................... 89
Center High Mounted Stop Light............ 481
Center Lap Belts......................... 43
Center Seat Storage Compartment.........176,177
Certification Label....................... 355
Charge Air Cooler....................... 450
Chart, Tire Sizing........................ 327
Check Engine Light
(Malfunction Indicator Light)............... 202
Child Restraint........................ 60,61
Child Restraint Tether Anchors............. 65,69
Child Seat............................ 61,68
Cigar Lighter........................... 171Cleaning
Wheels............................. 465
Climate Control......................... 257
Clock .....................207,211,219,232,245
Clutch Linkage Maintenance................ 453
Compact Disc (CD) Maintenance............. 256
Compact Spare Tire...................... 338
Compass...........................146,147
Compass Calibration..................147,158
Compass Variance....................148,158
Computer, Trip/Travel.................... 143
Console, Overhead....................142,150
Contract, Service........................ 526
Coolant Pressure Cap (Radiator Cap).......... 447
Cooling System......................... 444
Adding Coolant (Antifreeze).............. 447
Coolant Capacity...................... 487
Coolant Level...................444,445,448
Disposal of Used Coolant................ 448
536 INDEX

Drain, Flush, and Refill.................. 446
Inspection........................... 448
Points to Remember.................... 449
Pressure Cap......................... 447
Radiator Cap......................... 447
Selection of Coolant (Antifreeze).........446,488
Temperature Gauge..................... 200
Cruise Control (Speed Control).............. 139
CupHolder ............................ 172
Customer Assistance..................... 524
Customer Programmable Features............ 153
Data Recorder, Event...................... 58
Daytime Running Lights................... 131
Dealer Service.......................... 411
Defroster, Rear Window................. 88,181
Defroster, Windshield................ 77,258,261
Delay (Intermittent) Wipers................. 135
Diesel Exhaust Brake..................... 290Diesel Fuel............................ 348
Diesel Fuel Requirements.................. 348
Differential, Limited-Slip.................. 317
Dipsticks .............................. 414
Power Steering........................ 439
Disc Brakes............................ 451
Disposal.............................. 421
Engine Oil........................... 421
Used Coolant (Antifreeze)................ 448
Door Locks............................. 25
Door Locks, Automatic.................... 153
Door Opener, Garage..................... 160
Draining Fuel/Water Separator Filter.......427,430
DriveBelts ............................ 422
Dual Rear Wheels.....................347,396
DVD Player (Video Entertainment System)...... 249
Electric Rear Window Defrost............. 88,181
Electrical Power Outlets................... 169
INDEX 537
10