Page 320 of 406
Adding Diesel Exhaust Fluid
The DEF gauge (located on the instrument cluster) will
display the level of DEF remaining in the tank. Refer to
“Instrument Cluster” and “Instrument Cluster Descrip-
tions” in “Understanding Your Instrument Panel” for
further information.
NOTE:Driving conditions (altitude, vehicle speed, load,
etc.) will effect the amount of DEF that is used in your
vehicle.
Another factor is that outside temperature can affect DEF
consumption. In cold conditions, 12° F (-11° C) and
below, the DEF gauge needle can stay on a fixed position
and may not move for extended periods of time. This is
a normal function of the system.
DEF Fill Procedure
NOTE: Refer to “Fluids, Lubricants, and Genuine Parts”
in “Maintaining Your Vehicle” for the correct fluid type.
1. Remove cap from DEF tank (located on drivers side of the vehicle or in fuel door).
DEF Filler Cap Chassis Cab Models
318 STARTING AND OPERATING
Page 362 of 406

•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 engine coolant (antifreeze)
performance, poor gas mileage, and increased emis-
sions.
Charge Air Cooler — Inter-Cooler
The charge air cooler is positioned below 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°F
(10° to 38°C). 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 the
hoses leading to and from the charge air cooler for cracks
or loose clamps resulting in loss of pressure and reduced
engine performance.
Brake System
Brake Master Cylinder — Brake Fluid Level Check
The fluid level of the master cylinder should be checked
when performing under the hood service, or immedi-
ately if the “Brake System Warning Light” indicates
system failure.
The brake master cylinder has a translucent plastic
reservoir. On the outboard side of the reservoir, there is a
“MAX” mark and a “MIN” mark. The fluid level must be
kept within these two marks. Do not add fluid above the
full mark because leakage may occur at the cap.
360 MAINTAINING YOUR VEHICLE
Page 394 of 406

Adding Engine Coolant (Antifreeze)............140
Adding Fuel .............................114
Air Bag Light .............................25
Air Cleaner, Engine (Engine Air Cleaner Filter) . . . .128
Alarm (Security Alarm) ......................28
Antifreeze (Engine Coolant) ..................139
Capacities ........................... .146
Disposal ............................. .142
Automatic Transmission Fluid Type ........................... .150
Axle Fluid ............................. .150
Battery .................................30
Charging System Light ....................30
Brake Fluid ............................ .150
Brake System ........................... .144
Fluid Check .......................... .144
Master Cylinder ....................... .144Warning Light
..........................26
Capacities, Antifreeze (Engine Coolant) ..........146
Capacities, Fluid ......................... .146
Caps, Filler Oil (Engine) .......................... .127
Radiator (Coolant Pressure) ................142
Charge Air Cooler ........................ .144
Coolant Pressure Cap (Radiator Cap) ...........142
Cooling System .......................... .138
Adding Coolant (Antifreeze) ...............140
Coolant Capacity ...................... .146
Coolant Level ......................... .138
Disposal Of Used Coolant .................142
Drain, Flush, And Refill ...................139
Points To Remember .....................143
Pressure Cap ......................... .142
Radiator Cap ......................... .142
Selection Of Coolant (Antifreeze) ........139 , 147
8
INDEX - RAM 1500 391
Page 399 of 406

Adding Engine Coolant (Antifreeze)............356
Adding Fuel ............................ .312
Air Bag Light ........................... .191
Air Cleaner, Engine (Engine Air Cleaner Filter) . . . .340
Air Filter .............................. .340
Alarm (Security Alarm) .....................194
Antifreeze (Engine Coolant) ..................355
Capacities ........................... .373
Disposal ............................. .358
Automatic Transmission Adding Fluid ......................... .365
Fluid Level Check ...................... .364
Fluid Type ........................... .377
Shifting ............................. .286
Axle Fluid ............................. .377
Battery ................................ .196
Blanket .......................... .274 , 354Charging System Light
...................196
Emergency Starting ..................... .326
Brake System ........................... .360
Fluid Check .......................... .360
Master Cylinder ....................... .360
Warning Light ........................ .192
Brake/Transmission Interlock .................286
Capacities, Antifreeze (Engine Coolant) ..........373
Capacities, Fluid ......................... .373
Caps, Filler Oil (Engine) .......................... .338
Radiator (Coolant Pressure) ................358
Charge Air Cooler ........................ .360
Coolant Pressure Cap (Radiator Cap) ...........358
Cooling System .......................... .354
Adding Coolant (Antifreeze) ...............356
Coolant Capacity ...................... .373
Coolant Level ......................... .354
396 INDEX - RAM 2500 / 3500 / 4500 / 5500