2008 GMC ENVOY fuel additives

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Oil Life System..................................5-19
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Engine Coolant.............................................5-26
Radiator Pressure Cap..................................5-28
Engine Overheating.......................................5-28
Cooling System............................................5-30Engine Fan Noise.........................................5-35
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37
Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle.......................................................5-46
Four-Wheel Drive............................................5-47
Front Axle......................................................5-48
Headlamp Aiming...........................................5-49
Bulb Replacement..........................................5-49
Halogen Bulbs..............................................5-49
Headlamps..................................................5-50
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-51
Taillamps, Turn Signal, and Stoplamps............5-51
Back-Up Lamps............................................5-53
License Plate Lamp......................................5-53
Replacement Bulbs.......................................5-54
Windshield Wiper Blade Replacement..............5-54
Tires..............................................................5-57
Tire Sidewall Labeling...................................5-58
Tire Terminology and Denitions.....................5-61
Ination - Tire Pressure.................................5-64
Section 5 Service and Appearance Care
5-1

Gasoline Octane
Use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you might notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking, the
engine needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM specication
D 4814 in the United States or CAN/CGSB-3.5 or 3.511
in Canada. Some gasolines contain an octane-enhancing
additive called methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend against the use of
gasolines containing MMT. SeeAdditives on page 5-7for
additional information.
California Fuel
If your vehicle is certied to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specications. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, your vehicle will operate
satisfactorily on fuels meeting federal specications, but
emission control system performance might be affected.
The malfunction indicator lamp could turn on and your
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-41. If this occurs, return to your
authorized dealer/retailer for diagnosis. If it is determined
that the condition is caused by the type of fuel used,
repairs might not be covered by your warranty.
5-6

Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In most
cases, you should not have to add anything to the fuel.
However, some gasolines contain only the minimum
amount of additive required to meet U.S. Environmental
Protection Agency regulations. To help keep fuel injectors
and intake valves clean, or if your vehicle experiences
problems due to dirty injectors or valves, look for gasoline
that is advertised as TOP TIER Detergent Gasoline. Also,
your dealer/retailer has additives that will help correct and
prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines might be available
in your area. We recommend that you use these
gasolines, if they comply with the specications described
earlier. However, E85 (85% ethanol) and other fuels
containing more than 10% ethanol must not be used in
vehicles that were not designed for those fuels.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under your
warranty.Some gasolines that are not reformulated for low
emissions can contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. We recommend against
the use of such gasolines. Fuels containing MMT can
reduce the life of spark plugs and the performance of the
emission control system could be affected. The
malfunction indicator lamp might turn on. If this occurs,
return to your dealer/retailer for service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might be hard
to nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
be covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-7

A
Accessories and Modications............................ 5-3
Adding a Snow Plow or Similar Equipment.........4-40
Adding Equipment to Your
Airbag-Equipped Vehicle...............................1-66
Additives, Fuel................................................. 5-7
Add-On Electrical Equipment...........................5-109
Adjustable Throttle and Brake Pedal..................2-24
Air Cleaner/Filter, Engine.................................5-21
Air Conditioning......................................3-21, 3-23
Airbag
Passenger Status Indicator...........................3-34
Readiness Light..........................................3-33
Airbag System................................................1-53
What Will You See After an Airbag Inates?....1-60
When Should an Airbag Inate?....................1-58
Where Are the Airbags?...............................1-56
Airbag Systems
Adding Equipment to Your
Airbag-Equipped Vehicle............................1-66
How Does an Airbag Restrain?......................1-59
Passenger Sensing System...........................1-61
Servicing Your Airbag-Equipped Vehicle..........1-66
What Makes an Airbag Inate?......................1-59
Antenna, Fixed Mast......................................3-103Antenna, XM™ Satellite Radio
Antenna System........................................3-103
Antilock Brake System (ABS)............................. 4-4
Antilock Brake, System Warning Light................3-39
Appearance Care
Aluminum Wheels......................................5-105
Care of Safety Belts...................................5-103
Chemical Paint Spotting..............................5-106
Cleaning Exterior Lamps/Lenses..................5-104
Fabric/Carpet............................................5-101
Finish Care...............................................5-104
Finish Damage..........................................5-106
Instrument Panel, Vinyl, and
Other Plastic Surfaces.............................5-102
Interior Cleaning........................................5-100
Leather....................................................5-102
Sheet Metal Damage..................................5-106
Tires........................................................5-106
Underbody Maintenance.............................5-106
Vehicle Care/Appearance Materials...............5-107
Washing Your Vehicle.................................5-103
Weatherstrips............................................5-103
Windshield, Backglass, and Wiper Blades......5-105
Appointments, Scheduling Service.....................7-10
Ashtray.........................................................3-20
1

E
EDR .............................................................7-18
Electrical System
Add-On Equipment.....................................5-109
Engine Compartment Fuse Block.................5-110
Fuses and Circuit Breakers.........................5-110
Headlamps...............................................5-109
Power Windows and Other Power Options....5-109
Rear Underseat Fuse Block.........................5-116
Windshield Wiper Fuses.............................5-109
Electronically Controlled Air Suspension System . . . 4-44
Engine
Air Cleaner/Filter.........................................5-21
Change Engine Oil Light...............................3-45
Check and Service Engine Soon Light............3-41
Coolant......................................................5-26
Coolant Heater............................................2-24
Coolant Temperature Gage...........................3-40
Drive Belt Routing.......................................6-15
Engine Compartment Overview......................5-12
Exhaust.....................................................2-37
Fan Noise..................................................5-35
Oil .............................................................5-16
Oil Life System...........................................5-19
Overheating................................................5-28
Reduced Power Light...................................3-46
Starting......................................................2-22
Entry Lighting.................................................3-18
Event Data Recorders.....................................7-18Exit Lighting...................................................3-18
Extender, Safety Belt.......................................1-31
F
Filter
Engine Air Cleaner......................................5-21
Finish Damage.............................................5-106
Fixed Mast Antenna.......................................3-103
Flashers, Hazard Warning.................................. 3-6
Flash-to-Pass................................................... 3-8
Flat Tire........................................................5-81
Flat Tire, Changing.........................................5-82
Flat Tire, Storing.............................................5-96
Fluid.............................................................5-23
Power Steering...........................................5-36
Windshield Washer......................................5-37
Fog Lamp
Fog ...........................................................3-16
Four-Wheel Drive....................................2-29, 5-47
Front Axle......................................................5-48
Fuel............................................................... 5-5
Additives...................................................... 5-7
California Fuel.............................................. 5-6
Check Gas Cap Light...................................3-49
Filling a Portable Fuel Container....................5-10
Filling the Tank............................................. 5-8
Fuels in Foreign Countries.............................. 5-7
Gage.........................................................3-48
5