2007 GMC ENVOY fuel

If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on the ignition
system and your vehicle can stall. Stalling can also
occur if you get the tailpipe under water. And,
as long as the tailpipe is under water, you will
never be able to start the engine. When you go
through water, remember that when the brakes get
wet, it may take you longer to stop.
{CAUTION:
Driving through rushing water can be
dangerous. Deep water can sweep your
vehicle downstream and you and your
passengers could drown. If it is only
shallow water, it can still wash away the
ground from under your tires, and you
could lose traction and roll the vehicle
over. Do not drive through rushing water.
SeeDriving in Rain and on Wet Roads on page 335
for more information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on
the underbody, chassis, or under the hood.
These accumulations can be a re hazard.
After operation in mud or sand, have the brake
linings cleaned and checked. These substances
can cause glazing and uneven braking. Check the
body structure, steering, suspension, wheels, tires,
and exhaust system for damage. Also, check the
fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service
due to off-road use. Refer to the Maintenance
Schedule for additional information.
333

Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir
full? Are all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you
checked all levels?
Lamps:Are they all working? Are the lenses
clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough
for long-distance driving? Are the tires
all inated to the recommended pressure?
Weather Forecasts:What is the weather
outlook along your route? Should you
delay your trip a short time to avoid a major
storm system?
Maps:Do you have up-to-date maps?
Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of the
tires on the road, the drone of the engine, and the
rush of the wind against the vehicle that can make
you sleepy. Do not let it happen to you! If it does,
your vehicle can leave the road in less than a
second, and you could crash and be injured.
What can you do about highway hypnosis?
First, be aware that it can happen.
Then here are some tips:
Make sure your vehicle is well ventilated, with
a comfortably cool interior.
Keep your eyes moving. Scan the road ahead
and to the sides. Check your mirrors and your
instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
341

{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO
(carbon monoxide) gas to get inside.
CO could overcome you and kill you.
You cannot see it or smell it, so you might
not know it is in your vehicle. Clear away
snow from around the base of your
vehicle, especially any that is blocking
your exhaust pipe. And check around
again from time to time to be sure snow
does not collect there.
Open a window just a little on the side of
the vehicle that is away from the wind.
This will help keep CO out.Run your engine only as long as you must.
This saves fuel. When you run the engine, make it
go a little faster than just idle. That is, push the
accelerator slightly. This uses less fuel for the heat
that you get and it keeps the battery charged.
You will need a well-charged battery to restart the
vehicle, and possibly for signaling later on with
your headlamps. Let the heater run for a while.
Then, shut the engine off and close the window
almost all the way to preserve the heat. Start
the engine again and repeat this only when you
feel really uncomfortable from the cold. But do it
as little as possible. Preserve the fuel as long
as you can. To help keep warm, you can get out
of the vehicle and do some fairly vigorous
exercises every half hour or so until help comes.
347

This is called Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel, cargo, and trailer
tongue weight, if pulling a trailer.
The Certication/Tire label also tells you the
maximum weights for the front and rear axles,
called Gross Axle Weight Rating (GAWR). To nd
out the actual loads on your front and rear axles,
you need to go to a weigh station and weigh your
vehicle. Your dealer can help you with this. Be sure
to spread out your load equally on both sides of the
centerline.
Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
And, if you do have a heavy load, you should
spread it out.
Similar appearing vehicles may have different
GVWRs and capacity weights. Please note your
vehicle’s Certication/Tire label or consult
your dealer for additional details.
{CAUTION:
Do not load your vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do,
parts on your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
Using heavier suspension components to get
added durability might not change your vehicle’s
weight ratings. Ask your dealer to help you
load your vehicle the right way.
Notice:Overloading your vehicle may cause
damage. Repairs would not be covered by your
warranty. Do not overload your vehicle.
353

Towing a Trailer
{CAUTION:
If you do not use the correct equipment
and drive properly, you can lose control
when you pull a trailer. For example, if the
trailer is too heavy, the brakes may not
work well — or even at all. You and your
passengers could be seriously injured.
Pull a trailer only if you have followed all
the steps in this section. Ask your dealer
for advice and information about towing a
trailer with your vehicle.
Notice:Pulling a trailer improperly can
damage your vehicle and result in costly
repairs that would not be covered by your
warranty. Always follow the instructions in this
section and check with your dealer for more
information about towing a trailer with
your vehicle.To identify the trailering capacity of your vehicle,
you should read the information in “Weight of
the Trailer” that appears later in this section.
Trailering is different than just driving your vehicle
by itself. Trailering means changes in acceleration,
braking, handling, durability and fuel economy.
Successful, safe trailering takes correct equipment,
and it has to be used properly.
That’s the reason for this part. In it are many
time-tested, important trailering tips and safety
rules. Many of these are important for your safety
and that of your passengers. So please read
this section carefully before you pull a trailer.
362

Service........................................................ 380
Accessories and Modications................... 380
California Proposition 65 Warning.............. 381
Doing Your Own Service Work.................. 381
Adding Equipment to the Outside of
Your Vehicle.......................................... 382
Fuel............................................................. 382
Gasoline Octane........................................ 382
Gasoline Specications.............................. 383
California Fuel........................................... 383
Additives................................................... 383
Fuels in Foreign Countries........................ 384
Filling the Tank......................................... 385
Filling a Portable Fuel Container............... 387
Checking Things Under the Hood.............. 388
Hood Release........................................... 388
Engine Compartment Overview.................. 390
Engine Oil................................................. 394
Engine Oil Life System.............................. 398
Engine Air Cleaner/Filter............................ 400
Automatic Transmission Fluid.................... 401
Engine Coolant.......................................... 405Radiator Pressure Cap.............................. 408
Engine Overheating................................... 408
Cooling System......................................... 411
Engine Fan Noise..................................... 416
Power Steering Fluid ................................. 417
Windshield Washer Fluid........................... 418
Brakes...................................................... 419
Battery...................................................... 422
Jump Starting............................................ 423
Rear Axle.................................................... 428
Four-Wheel Drive........................................ 428
Front Axle................................................... 429
Bulb Replacement....................................... 430
Halogen Bulbs........................................... 430
Headlamps................................................ 431
Front Turn Signal, Sidemarker and
Parking Lamps....................................... 432
Taillamps, Turn Signal, and Stoplamps...... 432
Back-Up Lamps......................................... 434
License Plate Lamp................................... 435
Replacement Bulbs................................... 435
Section 5 Service and Appearance Care
377

Your vehicle has an airbag system. Before
attempting to do your own service work, see
Servicing Your Airbag-Equipped Vehicle on
page 88.
You should keep a record with all parts receipts
and list the mileage and the date of any service
work you perform. SeeMaintenance Record
on page 521.
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. To
help keep your engine clean and maintain optimum
vehicle performance, GM recommends the use
of gasoline advertised as TOP TIER Detergent
Gasoline.
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.
382

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 383for 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 may be affected. The
malfunction indicator lamp may turn on and your
vehicle may fail a smog-check test. SeeMalfunction
Indicator Lamp on page 210. 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.
383