2007 RAM CHASSIS CAB 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. STARTING AND OPERATING 263
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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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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
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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
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Automatic Transmission (Gas Engine Only) ..... 441
AxleFluid .......................... 437,471
Axle Lubrication (Axle Fluid) ............... 437
BallJoints ............................. 422
Battery ............................ 418,419
Blanket .......................... 260,420
Emergency Starting ..................... 382
Keyless Transmitter Replacement (RKE) ....... 24
Saving Feature (Protection) ............... 123
Bearings .............................. 444
Belts,Drive ............................ 406
Belts, Seat .............................. 35
Body Mechanism Lubrication ............... 423
B-Pillar Location ........................ 310
Brake Fluid ............................ 471
Brake System ........................ 301,434
Anti-Lock (ABS) ....................... 302
Disc Brakes .......................... 434 Fluid Check .......................... 435
Hoses .............................. 434
Master Cylinder ....................... 435
Parking ............................. 299
Warning Light ........................ 177
Bulb Replacement ....................... 462
Bulbs,Light ............................ 461
Cab Top Clearance Lights .................. 466
Calibration, Compass .................. 138,148
Capacities, Antifreeze (Engine Coolant) ........ 468
Capacities, Fluid ........................ 468
Caps, Filler
Oil (Engine) ....................... 401,403
Power Steering ........................ 421
Radiator (Coolant Pressure) ............... 429
Car Washes ............................ 452
Carbon Monoxide Warning ............... 75,330
Cassette Tape and Player Maintenance ......... 228 INDEX 515
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Catalyst Full Message ..................... 415
Catalytic Converter ...................... 413
CD (Compact Disc) Player ............ 182,190,204
Cellular Phone .......................... 87
Center Lap Belts ......................... 45
Center Seat Storage Compartment ......... 155,157
Certification Label ....................... 338
Charge Air Cooler ....................... 432
Chart, Tire Sizing ........................ 306
Check Engine Light (Malfunction Indicator Light) . 176
Child Restraint ........................ 59,60
Child Restraint Tether Anchors ............. 64,67
Child Seat ............................ 60,66
Cigar Lighter ........................... 151
Cleaning
Wheels ............................. 454
Climate Control ......................... 230
Clock ..................... 180,185,192,205,219
Clutch Linkage Maintenance ................ 436 Compact Disc (CD) Maintenance ............. 229
Compact Spare Tire ...................... 318
Compass .............................. 138
Compass Calibration .................. 138,148
Compass Variance .................... 140,148
Computer, Trip/Travel .................... 134
Console, Overhead ....................... 141
Contract, Service ........................ 506
Coolant Pressure Cap (Radiator Cap) .......... 429
Cooling System ......................... 426
Adding Coolant (Antifreeze) .............. 429
Coolant Capacity ...................... 468
Coolant Level ................... 426,427,430
Disposal of Used Coolant ................ 430
Drain, Flush, and Refill .................. 427
Inspection ........................... 430
Points to Remember .................... 431
Pressure Cap ......................... 429
Radiator Cap ......................... 429516 INDEX

Seats ............................... 116
Sliding Rear Window ................. 33,160
Steering .......................... 304,421
Take-Off Adapter ...................... 296
Take-Off Operation ..................... 296
Windows ............................. 32
Power Steering Fluid ..................... 471
Pregnant Women and Seat Belts .............. 47
Pretensioners
Seat Belts ............................. 45
Programmable Electronic Features ............ 145
PTO (Power Take-Off) .................... 296
Radial Ply Tires ......................... 317
Radiator Cap (Coolant Pressure Cap) .......... 429
Radio Broadcast Signals ................... 181
Radio, Navigation ....................... 218
Radio Operation ................... 182,190,204
Radio Remote Controls .................... 226 Radio, Satellite ....................... 219,222
Radio (Sound Systems) .............. 182,190,204
Rear Axle (Differential) ................. 436,437
Rear Wheel Bearings ..................... 445
Rear Window Features .................... 160
Rear Window, Sliding ................... 34,161
Reclining Front Seats ..................... 114
Recorder, Event Data ...................... 57
Recreational Towing ...................... 360
Shifting into Transfer Case Neutral (N) .... 361,363
Shifting out of Transfer Case Neutral (N) . . . 362,365
Reformulated Gasoline .................... 328
Refrigerant ............................ 421
Reminder, Seat Belt ....................... 46
Remote Keyless Entry (RKE) ................. 20
Remote Sound System (Radio) Controls ........ 226
Remote Starting System .................... 25
Replacement Tires ....................... 321
Reporting Safety Defects ................... 507 INDEX 525
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