2008 JEEP GRAND CHEROKEE octane

5.7L Engines (If Equipped)
The 5.7L engine is designed to meet all
emissions regulations and provide satisfac-
tory fuel economy and performance when
using high quality unleaded gasoline hav-
ing an octane range of 87 to 89. The manu-
facturer recommends the use of 89 octane
for optimum performance. The use of premium gasoline
is not recommended. Under normal conditions, the use of
premium gasoline will not provide a benefit over high
quality regular and mid-grade gasolines, and in some
circumstances may result in poorer performance.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required.Poor quality gasoline can cause problems such as hard
starting, stalling and hesitations. If you experience these
symptoms, try another brand of gasoline before consid-
ering service for the vehicle.
Over 40 auto manufacturer's world wide have issued and
endorsed consistent gasoline specifications (the World-
wide Fuel Charter, WWFC) to define fuel properties
necessary to deliver enhanced emissions, performance,
and durability for your vehicle. The manufacturer recom-
mends the use of gasoline that meets the WWFC speci-
fications if they are available.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning gasoline referred to as ªReformulated Gasoline.º
Reformulated gasoline contains oxygenates, and are spe-
cifically blended to reduce vehicle emissions and im-
prove air quality.
STARTING AND OPERATING 337
5

The manufacturer supports the use of reformulated gaso-
line. Properly blended reformulated gasoline will pro-
vide excellent performance and durability of engine and
fuel system components.
Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxy-
genates such as 10% ethanol, MTBE, and ETBE. Oxygen-
ates are required in some areas of the country during the
winter months to reduce carbon monoxide emissions.
Fuels blended with these oxygenates may be used in
your vehicle.
CAUTION!
DO NOT use gasoline containing Methanol or E85
Ethanol. Use of these blends may result in starting
and driveability problems and may damage critical
fuel system components.Problems that result from using methanol/gasoline
blends are not the responsibility of the manufacturer.
While MTBE is an oxygenate made from Methanol, it
does not have the negative effects of Methanol.
MMT In Gasoline
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. Gasoline blended with MMT reduces spark plug
life and reduces emission 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
or not his/her gasoline contains MMT.
338 STARTING AND OPERATING

It is even more important to look for gasolines without
MMT in Canada, because MMT can be used at levels
higher than those allowed in the United States.
MMT is prohibited in Federal and California reformu-
lated gasoline.
Materials Added To Fuel
All gasoline sold in the United States is required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in additional cost. Therefore
you should not have to add anything to the fuel.
Fuel System Cautions
CAUTION!
Follow these guidelines to maintain your vehicle's
performance:
²The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine performance,
damage the emission control system.
²An 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 dealer for service assistance.
²The use of fuel additives which are now being sold as
octane enhancers is not recommended. Most of these
products contain high concentrations of methanol.
Fuel system damage or vehicle performance problems
resulting from the use of such fuels or additives is not
the responsibility of the manufacturer.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
STARTING AND OPERATING 339
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WARNING!
Ethanol vapors are extremely flammable and could
cause serious personal injury. Never have any smok-
ing materials lit in or near the vehicle when remov-
ing 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
Your vehicle will operate on both unleaded gasoline with
an octane rating of 87, or E-85 fuel, or any mixture of
these two.For best results, a refueling pattern that alternates be-
tween E-85 and unleaded gasoline should be avoided.
When you do switch fuels, it is recommended that
²you do not switch when the fuel gauge indicates less
than 1/4 full
²you do not add less than 5 gallons when refueling
²you operate the vehicle immediately after refueling for
a period of at least 5 minutes
Observing these precautions will avoid possible hard
starting and/or significant deterioration in drivability
during warm up.
NOTE:When the ambient temperature is above 90ÉF
(32ÉC), you may experience hard starting and rough idle
following start up even if the above recommendations are
followed.
342 STARTING AND OPERATING

FLUIDS, LUBRICANTS, AND GENUINE PARTS
Engine
Component Fluid, Lubricant, or Genuine Part
Engine Coolant MopartAntifreeze/Coolant 5 Year/100,000 Mile Formula HOAT (Hy-
brid Organic Additive Technology)
Engine Oil (3.7L/4.7L/5.7L Engines) Use API Certified SAE 5W-20 Engine Oil, meeting the requirements of
DaimlerChrysler Material Standard MS-6395. Refer to your engine oil
filler cap for correct SAE grade.
Engine Oil (3.0L Diesel Engine)
Use API Certified SAE 5W-30 Synthetic Low Ash Engine Oil, meeting the
requirements of DaimlerChrysler Material Standard MS-11106, Mercedes
Benz MB 229.31 or 229.51, and ACEA C3 qualified engine oils.
Oil Filter (3.7/4.7/5.7L Gasoline Engines) MopartOil Filter (P/N 05281090)
Oil Filter (3.0L Diesel Engine) MopartOil Filter (P/N 05175571AA)
Spark Plugs (3.7L Engine) ZFR6F-11G (Gap 0.043º)
Spark Plugs (4.7L Engine) Upper Bank Ð FR8TE2 (Gap 0.040º) Lower Bank Ð FR8T1332 (Gap
0.050º)
Spark Plugs (5.7L Engine) REC14MCC4 (Gap 0.043º)
Fuel Selection (3.7L and 4.7L Engines) 87 Octane
MAINTAINING YOUR VEHICLE 441
7

Component Fluid, Lubricant, or Genuine Part
Fuel Selection (5.7L Engines) 87 Octane Acceptable - 89 Octane Recommended
Fuel Selection (3.0L Diesel Engines) Use only the best quality fuel with a calculated Cetane Index of 42±46.
In addition, the manufacturer recommends using diesel fuel with a
sulfur content ofless than or equal to 15 ppm.
Chassis
Component Fluid, Lubricant, or Genuine Part
Automatic Transmission MopartATF+4 Automatic Transmission Fluid
Transfer Case (NV140 Single Speed Only) MopartATF+4 Automatic Transmission Fluid
Transfer Case (NV245 Two Speed Only) MopartNV 247/245 Transfer Case Lubricant
Axle Differential (Front-Rear) MopartSynthetic Gear & Axle Lubricant SAE 75W-140 (API-GL5)
or equivalent with friction modifier additive.
Brake Master Cylinder MopartDOT 3 Brake Fluid, SAE J1703 should be used. If DOT 3,
SAE J1703 brake fluid is not available, then DOT 4 is acceptable.
Use only recommended brake fluids.
Power Steering Reservoir This system requires the use of MopartHydraulic System Power
Steering Fluid (P/N 05142893AA) or equivalent, which meets
DaimlerChrysler Material Standard MS-10838.
442 MAINTAINING YOUR VEHICLE

Fluids, Lubricants and Genuine Parts.......... 441
Fog Light Service........................ 437
Fog Lights.......................127,195,437
Folding Rear Seat........................ 115
Four Wheel Drive....................... 293
Operation........................... 293
Systems............................. 293
Four Wheel Drive Operation................ 293
Four-Way Hazard Flasher.................. 370
Freeing A Stuck Vehicle................... 292
Front Axle (Differential)................... 415
Front Heated Seats....................... 111
Fuel................................. 336
Diesel.............................. 344
Filler Cap (Gas Cap).................... 346
Gasoline............................ 336
Gauge.............................. 195
Hoses.............................. 412
Materials Added....................... 339Octane Rating......................336,337
Requirements......................... 440
System Hoses......................... 412
Tank Capacity........................ 440
Fuel, Flexible.............See Flexible Fuel Vehicles
Fuel System Caution................339,346,348
Fuses................................ 426
Garage Door Opener (HomeLinkt) ........... 158
Gas Cap (Fuel Filler Cap)............346,348,391
Gasoline (Fuel)......................... 336
Gasoline, Reformulated................... 337
Gasoline/Oxygenate Blends................ 338
Gauges
Coolant Temperature.................... 192
Fuel................................ 195
Speedometer......................... 188
Tachometer.......................... 190
Gear Ranges........................... 286
476 INDEX

Memory Seat........................... 118
Memory Seats and Radio.................. 118
Mini-Trip Computer...................... 201
Mirrors................................ 77
Automatic Dimming..................... 78
Electric Powered....................... 79
Electric Remote........................ 79
Exterior Folding........................ 79
Heated.............................. 80
Outside.............................. 78
Rearview............................. 77
Vanity............................... 80
Modifications/Alterations, Vehicle............. 9
Monitor, Tire Pressure System............... 326
Mopar Parts.........................393,463
MP3 Player............................ 241
Multi-Displacement Engine System........... 309
Multi-Function Control Lever............... 123Navigation Radio........................ 244
Navigation System....................... 244
New Vehicle Break-In Period................ 68
Occupant Restraints....................... 36
Octane Rating, Gasoline (Fuel)............336,337
Odometer..........................193,194
Trip ................................ 193
Off-Pavement Driving (Off-Road)..........300,420
Off-Road Driving (Off-Pavement)..........300,420
Oil Change Indicator..................... 201
Oil Change Indicator, Reset................. 201
Oil, Engine............................ 394
Capacity............................ 440
Change Interval....................... 395
Dipstick............................. 394
Disposal............................ 397
Filter............................... 397
Filter Disposal........................ 397
INDEX 481
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