2015 Ram 1500 heating

Operating Precautions
Avoid Overheating The Engine
The temperature of the engine coolant (antifreeze) (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 21 psi (145 kPa) coolant pressure cap.
Usually the engine coolant (antifreeze) temperature indi-
cated during operation will be to the left of center in the
normal range of the gauge.
Avoid Low Coolant Temperature Operation
Continual operation at low engine coolant (antifreeze)
temperature below the normal range on the gauge 140°F
(60°C) can be harmful to the engine. Low engine coolant
(antifreeze) temperature can cause incomplete combus-
tion which allows carbon and varnish to form on pistonrings 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, shift the transmission into NEUTRAL
and increase engine idle speed.
• Highway Driving —
Reduce your speed.
• Up Steep Hills —
Select a lower transmission gear.
• Air Conditioning —
Turn it off temporarily.
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If the transmission temperature exceeds normal operat-
ing limits, the powertrain controller will modify the
transmission shift schedule and expand the range of
torque converter clutch engagement. This is done to
prevent transmission damage due to overheating.
If the transmission becomes extremely hot or is in danger
of overheating, the “Transmission Temperature Warning
Light” may illuminate and the transmission may operate
differently until the transmission cools down.
NOTE:Use caution when operating a heavily loaded
vehicle at low speeds (such as towing a trailer up a steep
grade, or in stop-and-go traffic) during hot weather. In
these conditions, torque converter slip can impose a
significant additional heat load on the cooling system.
Downshifting the transmission to the lowest possible
gear (when climbing a grade), or shifting to NEUTRAL
(when stopped in heavy traffic) can help to reduce this
excess heat generation. During cold temperatures, transmission operation may
be modified depending on engine and transmission
temperature as well as vehicle speed. This feature im-
proves warm up time of the engine and transmission to
achieve maximum efficiency. Engagement of the torque
converter clutch is inhibited until the transmission fluid
is warm (refer to the “Note” under “Torque Converter
Clutch” in this section). On Pickup models with 68RFE
transmission, top overdrive gear is also inhibited until
the transmission fluid is warm, and during extremely
cold temperatures (-16°F [-27°C] or below), operation
may briefly be limited to first and direct gears only. On
trucks with AS69RC transmission, fifth and sixth gears
may be inhibited briefly on cold starts below 41°F (5°C),
and during very cold temperatures (-4°F [-20°C] or
below), operation may briefly be limited to third gear
only. During this condition, the ability of the vehicle to
238 STARTING AND OPERATING

•The engine coolant has reached an adequate tempera-
ture.
• The vehicle speed is sufficiently high.
• The driver is not heavily pressing the accelerator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the TOW/HAUL switch to activate TOW/
HAUL mode. This will improve performance and reduce
the potential for transmission overheating or failure due
to excessive shifting. When operating in TOW/HAUL
mode, transmission upshifts are delayed, and the trans-
mission will automatically downshift (for engine brak-
ing) when the throttle is closed and/or during steady
braking maneuvers.
The “TOW/HAUL Indicator Light” will illuminate in the
instrument cluster to indicate that TOW/HAUL mode has
been activated. Pressing the switch a second time restores
normal operation. Normal operation is always the default
at engine start-up. If TOW/HAUL mode is desired, the
switch must be pressed each time the engine is started.
TOW/HAUL Switch
242 STARTING AND OPERATING

CAUTION!(Continued)
•DO NOT OVERFILL. DEF will freeze below 12ºF
(-11ºC). The DEF system is designed to work in
temperatures below the DEF freezing point, how-
ever, if the tank is overfilled and freezes, the
system could be damaged.
• When DEF is spilled, clean the area immediately
with water and use an absorbent material to soak
up the spills on the ground.
• Do not attempt to start your engine if DEF is
accidentally added to the diesel fuel tank as it can
result in severe damage to your engine, including
but not limited to failure of the fuel pump and
injectors.
3. Stop filling the DEF tank immediately when any of the following happen: DEF stops flowing from the fill
bottle into the DEF tank, DEF splashes out the filler
neck, or a DEF pump nozzle automatically shuts off. 4. Reinstall cap onto DEF tank.
Filling The Def Tank In Cold Climates
Since DEF will begin to freeze at 12°F (-11°C), your vehicle
is equipped with an automatic DEF heating system. This
allows the DEF injection system to operate properly at
temperatures below 12°F (-11°C). If your vehicle is not in
operation for an extended period of time with tempera-
tures below 12°F (-11°C), the DEF in the tank may freeze. If
the tank is overfilled and freezes, it could be damaged.
Therefore, do not overfill the DEF tank.
Extra care should be taken when filling with portable
containers to avoid overfilling. Note the level of the DEF
gauge in your instrument cluster. On pickup applications,
you may safely add a maximum of 2 gallons of DEF from
portable containers when your DEF gauge is reading ½ full.
On Chassis Cab applications a maximum of 2 gallons may
be added when the DEF gauge is reading ¾ full.
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