Fuel Economy
Underinflated tires will increase tire rolling resistance
resulting in higher fuel consumption.
Tread Wear
Improper cold tire inflation pressures can cause abnormal
wear patterns and reduced tread life, resulting in the need
for earlier tire replacement.
Ride Comfort And Vehicle Stability
Proper tire inflation contributes to a comfortable ride.
Over-inflation produces a jarring and uncomfortable ride.
Tire Inflation Pressures
The proper cold tire inflation pressure is listed on the
driver’s side B-Pillar or rear edge of the driver’s side door.
At least once a month:
•Check and adjust tire pressure with a good quality
pocket-type pressure gauge. Do not make a visual
judgement when determining proper inflation. Tires
may look properly inflated even when they are under-
inflated.
• Inspect tires for signs of tire wear or visible damage.
CAUTION!
After inspecting or adjusting the tire pressure, always
reinstall the valve stem cap. This will prevent moisture
and dirt from entering the valve stem, which could
damage the valve stem.
Inflation pressures specified on the placard are always
“cold tire inflation pressure”. Cold tire inflation pressure is
defined as the tire pressure after the vehicle has not been
driven for at least three hours, or driven less than 1 mile
(1.6 km) after sitting for a minimum of three hours. The
cold tire inflation pressure must not exceed the maximum
inflation pressure molded into the tire sidewall.
Check tire pressures more often if subject to a wide range
of outdoor temperatures, as tire pressures vary with tem-
perature changes.
Tire pressures change by approximately 1 psi (7 kPa) per
12°F (7°C) of air temperature change. Keep this in mind
when checking tire pressure inside a garage, especially in
the Winter.
Example: If garage temperature = 68°F (20°C) and the
outside temperature = 32°F (0°C) then the cold tire inflation
8
SERVICING AND MAINTENANCE 569
TECHNICAL SPECIFICATIONS
CONTENTS
IDENTIFICATION DATA ...................593
▫ Vehicle Identification Number .............593
BRAKE SYSTEM ........................593
▫ Hydraulic Brake Assist — 2500/3500 Models Only
(Except Power Wagon) ...................593
WHEEL AND TIRE TORQUE SPECIFICATIONS . .594
▫ Torque Specifications ....................594
FUEL REQUIREMENTS ...................596
▫ 3.6L Engine .......................... .596
▫ 5.7L Engine .......................... .596
▫ 6.4L Engine .......................... .597
▫ Reformulated Gasoline ..................597
▫ Materials Added To Fuel .................597
▫ Gasoline/Oxygenate Blends ...............598 ▫
Do Not Use E-85 In Non-Flex Fuel Vehicles . . . .598
▫ CNG And LP Fuel System Modifications ......599
▫ MMT In Gasoline .......................599
▫ Fuel System Cautions ....................599
▫ Carbon Monoxide Warnings ...............600
FLEXIBLE FUEL (3.6L ENGINE ONLY) ........600
▫ E-85 General Information .................600
▫ Ethanol Fuel (E-85) ..................... .600
▫ Fuel Requirements .....................601
▫ Selection Of Engine Oil For Flexible Fuel Vehicles
(E-85) And Gasoline Vehicles ..............601
▫ Starting ............................ .602
▫ Cruising Range ........................602
▫ Replacement Parts ..................... .602
9
FUEL REQUIREMENTS
3.6L Engine
This engine is designed to meet all emis-
sions regulations and provide excellent
fuel economy and performance when
using high-quality unleaded “Regular”
gasoline having an octane rating of 87 as
specified by the (R+M)/2 method. The
use of higher octane “Premium” gaso-
line will not provide any benefit over “Regular” gasoline in
these engines.
While operating on gasoline with an octane number of 87,
hearing a light knocking sound from the engine is not a
cause for concern. However, if the engine is heard making
a heavy knocking sound, see your dealer immediately. Use
of gasoline with an octane number lower than 87 can cause
engine failure and may void or not be covered by the New
Vehicle Limited Warranty.
Poor quality gasoline can cause problems such as hard
starting, stalling, and hesitations. If you experience these
symptoms, try another brand of gasoline before consider-
ing service for the vehicle.
5.7L Engine
Do not use E-85 flex fuel or ethanol blends greater than
15% in this engine.
This engine is designed to meet all emis-
sions regulations and provide satisfac-
tory fuel economy and performance
when using high-quality unleaded gaso-
line having an octane range of 87 to 89 as
specified by the (R+M)/2 method. The
use of 89 octane “Plus” gasoline is rec-
ommended for optimum performance and fuel economy.
While operating on gasoline with an octane number of 87,
hearing a light knocking sound from the engine is not a
cause for concern. However, if the engine is heard making
a heavy knocking sound, see your dealer immediately. Use
of gasoline with an octane number lower than 87 can cause
engine failure and may void or not be covered by the New
Vehicle Limited Warranty.
Poor quality gasoline can cause problems such as hard
starting, stalling, and hesitations. If you experience these
symptoms, try another brand of gasoline before consider-
ing service for the vehicle.
596 TECHNICAL SPECIFICATIONS
6.4L Engine
Do not use E-85 flex fuel or ethanol blends greater than
15% in this engine.This engines is designed to meet all
emissions regulations and provide satis-
factory fuel economy and performance
when using high quality unleaded gaso-
line having a posted octane number
range of 87 to 89 as specified by the
(R+M)/2 method. The use of 89 octane
“Plus” gasoline is recommended for optimum performance
and fuel economy.
While operating on gasoline with an octane number of 87,
hearing a light knocking sound from the engine is not a
cause for concern. However, if the engine is heard making
a heavy knocking sound, see your dealer immediately. Use
of gasoline with an octane number lower than 87 can cause
engine failure and may void or not be covered by the New
Vehicle Limited Warranty.
Poor quality gasoline can cause problems such as hard
starting, stalling, and hesitations. If you experience these
symptoms, try another brand of gasoline before consider-
ing service for the vehicle.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning gasoline referred to as “Reformulated Gasoline”.
Reformulated gasoline contains oxygenates and are specifi-
cally blended to reduce vehicle emissions and improve air
quality.
The use of reformulated gasoline is recommended. Prop-
erly blended reformulated gasoline will provide improved
performance and durability of engine and fuel system
components.
Materials Added To Fuel
Besides using unleaded gasoline with the proper octane
rating, gasolines that contain detergents, corrosion and
stability additives are recommended. Using gasolines that
have these additives will help improve fuel economy,
reduce emissions, and maintain vehicle performance.
Designated TOP TIER Detergent Gaso-
line contains a higher level of detergents
to further aide in minimizing engine
and fuel system deposits. When avail-
able, the usage of Top Tier Detergent
9
TECHNICAL SPECIFICATIONS 597
gasoline is recommended. Visit www.toptiergas.com for a
list of TOP TIER Detergent Gasoline Retailers.
Indiscriminate use of fuel system cleaning agents should be
avoided. Many of these materials intended for gum and
varnish removal may contain active solvents or similar
ingredients. These can harm fuel system gasket and dia-
phragm materials.
Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxygen-
ates such as ethanol.
CAUTION!
DO NOT use E-85, gasoline containing methanol, or
gasoline containing more than 15% ethanol (E-15). Use
of these blends may result in starting and drivability
problems, damage critical fuel system components,
cause emissions to exceed the applicable standard,
and/or cause the “Malfunction Indicator Light” to
illuminate. Please observe pump labels as they should
clearly communicate if a fuel contains greater than 15%
ethanol (E-15).Problems that result from using gasoline containing more
than 15% ethanol (E-15) or gasoline containing methanol
are not the responsibility of the manufacturer and may
void or not be covered under New Vehicle Limited War-
ranty.
Do Not Use E-85 In Non-Flex Fuel Vehicles
Non-Flex Fuel Vehicles (FFV) are compatible with gasoline
containing up to 15% ethanol (E-15). Use of gasoline with
higher ethanol content may void the New Vehicle Limited
Warranty.
If a Non-FFV vehicle is inadvertently fueled with E-85 fuel,
the engine will have some or all of these symptoms:
•
Operate in a lean mode.
• OBD II “Malfunction Indicator Light” on.
• Poor engine performance.
• Poor cold start and cold drivability.
• Increased risk for fuel system component corrosion.
598 TECHNICAL SPECIFICATIONS
CNG And LP Fuel System Modifications
Modifications that allow the engine to run on compressed
natural gas (CNG) or liquid propane (LP) may result in
damage to the engine, emissions, and fuel system compo-
nents. Problems that result from running CNG or LP are
not the responsibility of the manufacturer and may void or
not be covered under the New Vehicle Limited Warranty.
MMT In Gasoline
Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is
a manganese-containing metallic additive that is blended
into some gasoline to increase octane. Gasoline blended
with MMT provides no performance advantage beyond
gasoline of the same octane number without MMT. Gaso-
line blended with MMT reduces spark plug life and
reduces emissions system performance in some vehicles.
The manufacturer recommends that gasoline without
MMT be used in your vehicle. The MMT content of
gasoline may not be indicated on the gasoline pump;
therefore, you should ask your gasoline retailer whether
the gasoline contains MMT. MMT is prohibited in Federal
and California reformulated gasoline.
Fuel System Cautions
CAUTION!
Follow these guidelines to maintain your vehicle’s
performance:
•The use of leaded gasoline is prohibited by Federal
law. Using leaded gasoline can impair engine perfor-
mance and damage the emissions control system.
• An out-of-tune engine or certain fuel or ignition
malfunctions can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your authorized dealer for service assistance.
• The use of fuel additives, which are now being sold
as octane enhancers, is not recommended. Most of
these products contain high concentrations of metha-
nol. Fuel system damage or vehicle performance
problems resulting from the use of such fuels or
additives is not the responsibility of the manufac-
turer and may void or not be covered under the New
Vehicle Limited Warranty.
9
TECHNICAL SPECIFICATIONS 599
NOTE:Intentional tampering with the emissions control
system can result in civil penalties being assessed against
you.
Carbon Monoxide Warnings
WARNING!
Carbon monoxide (CO) in exhaust gases is deadly.
Follow the precautions below to prevent carbon mon-
oxide poisoning:
• Do not inhale exhaust gases. They contain carbon
monoxide, a colorless and odorless gas, which can
kill. Never run the engine in a closed area, such as a
garage, and never sit in a parked vehicle with the
engine running for an extended period. If the vehicle
is stopped in an open area with the engine running
for more than a short period, adjust the ventilation
system to force fresh, outside air into the vehicle.
• Guard against carbon monoxide with proper main-
tenance. Have the exhaust system inspected every
time the vehicle is raised. Have any abnormal condi-
tions repaired promptly. Until repaired, drive with
all side windows fully open.
FLEXIBLE FUEL (3.6L ENGINE ONLY)
E-85 General Information
The information in this section is unique for Flexible Fuel
vehicles only. These vehicles can be identified by a unique
fuel filler door label that states Ethanol (E-85) or Unleaded
Gasoline Only and/or a yellow fuel cap. Please refer to the
other sections of this manual for information on features
that are common between Flexible Fuel and non-Flexible
Fuel powered vehicles.
CAUTION!
Only vehicles with the E-85 fuel filler door label or a
yellow gas cap can operate on E-85.
Ethanol Fuel (E-85)
E-85 is a mixture of approximately 85% ethanol and 15%
unleaded gasoline.
WARNING!
Ethanol vapors are extremely flammable and could
cause serious personal injury. Never have any smoking
(Continued)
600 TECHNICAL SPECIFICATIONS
WARNING!(Continued)
materials lit or products that can cause spark in or near
the vehicle when removing the fuel filler tube cap (gas
cap) or filling the tank. Do not use E-85 as a cleaning
agent and never use it near an open flame.
Fuel Requirements
If your vehicle is E-85 compatible, it will operate on
unleaded gasoline with any octane rating, or solely E-85
fuel, or any mixture of these fuels.
For best results, avoid fueling patterns alternating be-
tween E-85 and unleaded gasoline.
When switching fuel types:
•Add 5 gallons (19 liters) or more when refueling.
• Drive the vehicle immediately after refueling for at least
5 miles (8 km).
Observing these precautions will avoid possible hard start-
ing and/or driveability problems during warm up. NOTE:
•
Use seasonally adjusted E-85 fuel (ASTM D5798). With
non-seasonally adjusted E-85 fuel, hard starting and
rough idle following start up may be experienced even if
the above recommendations are followed, especially
when the ambient temperature is below 32°F (0°C).
• Some additives used in regular gasoline are not fully
compatible with E-85 and may form deposits in your
engine. To eliminate driveability issues that may be
caused by these deposits, a supplemental gasoline addi-
tive, such as Mopar Injector Cleanup or Techron may be
used.
Selection Of Engine Oil For Flexible Fuel Vehicles
(E-85) And Gasoline Vehicles
FFV vehicles operated on E-85 require specially formulated
engine oils. These special requirements are included in
Mopar engine oils, and in equivalent oils meeting FCA US
Material Standard MS-6395. It is recommended that engine
oils that are API Certified and meet the requirements of
Material Standard MS-6395 be used. MS-6395 contains
additional requirements, developed during extensive fleet
testing, to provide additional protection to FCA US LLC
engines.
9
TECHNICAL SPECIFICATIONS 601