2006 GMC ENVOY Owner's Manual

Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airow around it. This may cause wind
noise and affect windshield washer performance. Check
with your dealer before adding equipment to the
outside of your vehicle.
Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle.
Gasoline Octane
Use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you may 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, your
engine needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT).
General Motors recommends against the use of
gasolines containing MMT. SeeAdditives on page 5-6
for additional information.
5-5

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 may be affected. The malfunction indicator
lamp may turn on and your vehicle may fail a
smog-check test. SeeMalfunction Indicator Lamp
on page 3-42. If this occurs, return to your authorized
GM dealer for diagnosis. If it is determined that the
condition is caused by the type of fuel used, repairs
may not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. In most cases, you should not have to add
anything to your 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
GM dealer has additives that will help correct and
prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area. General Motors recommends 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.
5-6

Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors
recommends against the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs
and the performance of the emission control system may
be affected. The malfunction indicator lamp may turn
on. If this occurs, return to your authorized GM dealer
for service.Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may 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

Filling the Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Keep sparks, ames, and smoking materials
away from fuel. Do not leave the fuel pump
unattended when refueling your vehicle — this
is against the law in some places. Keep
children away from the fuel pump; never let
children pump fuel.The tethered fuel cap is located behind a hinged fuel
door on the driver’s side of the vehicle.
To remove the fuel cap, turn it slowly counterclockwise.
While refueling, hang the tethered fuel cap from the
hook on the fuel door.
5-8

{CAUTION:
If you spill fuel and then something ignites it,
you could be badly burned. Fuel can spray out
on you if you open the fuel cap too quickly.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any hiss noise
to stop. Then unscrew the cap all the way.
Be careful not to spill fuel. Do not top off or overll the
tank and wait a few seconds after you have nished
pumping before removing the nozzle. Clean fuel
from painted surfaces as soon as possible. See
Washing Your Vehicle on page 5-96.
When replacing the fuel cap, turn it clockwise until it
clicks. Make sure the cap is fully installed. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. This would allow fuel
to evaporate into the atmosphere. SeeMalfunction
Indicator Lamp on page 3-42.There may also be a light that comes on in the
instrument panel to let you know if your gas cap is not
properly installed. SeeCheck Gas Cap Light on
page 3-49for more information.
{CAUTION:
If a re starts while you are refueling, do not
remove the nozzle. Shut off the ow of fuel by
shutting off the pump or by notifying the
station attendant. Leave the area immediately.
Notice:If you need a new fuel cap, be sure to get
the right type. Your dealer can get one for you.
If you get the wrong type, it may not t properly.
This may cause your malfunction indicator lamp to
light and may damage your fuel tank and emissions
system. SeeMalfunction Indicator Lamp on
page 3-42.
5-9

Filling a Portable Fuel Container
{CAUTION:
Never ll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the gasoline vapor.
You can be badly burned and your vehicle
damaged if this occurs. To help avoid injury to
you and others:
Dispense gasoline only into approved
containers.
Do not ll a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed, or
on any surface other than the ground.
Bring the ll nozzle in contact with the
inside of the ll opening before operating
the nozzle. Contact should be maintained
until the lling is complete.
Do not smoke while pumping gasoline.
Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
5-10

Hood Release
1. To open the hood, rst
pull the handle with this
symbol on it. It is
located inside the
vehicle under
the instrument panel
on the driver’s side.
2. Then go to the front of the vehicle and release the
secondary hood release.
3. Lift the hood, release the prop rod from its retainer
and put the prop rod into the slot in the hood.
Before closing the hood, be sure all the ller caps are
on properly. Then lift the hood to relieve pressure on the
prop rod. Remove the prop rod from its slot in the
hood and return the prop to its retainer. Lower the hood
6 to 8 inches (15 to 20 cm) above the vehicle and
release it to latch fully. Check to make sure the hood is
closed and repeat the process if necessary.
5-11

Engine Compartment Overview
When you open the hood on the 4.2L L6 engine, here is what you will see:
5-12