2004 GMC ENVOY XUV engine

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.
If You Do Decide To Pull A Trailer
If you do, here are some important points:
·There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you'll be driving. A good source for
this information can be state or provincial police.
·Consider using a sway control. See ªHitchesº later
in this section.
·Don't tow a trailer at all during the ®rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
·Then, during the ®rst 500 miles (800 km) that you
tow a trailer, don't drive over 50 mph (80 km/h)
and don't make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
·You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3) or, if necessary, a
lower gear selection if the transmission shifts
too often (e.g., under heavy loads and/or hilly
conditions).
Three important considerations have to do with weight:
·the weight of the trailer,
·the weight of the trailer tongue
·and the weight on your vehicle's tires.
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Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For example, speed, altitude, road grades, outside temperature and how
much your vehicle is used to pull a trailer are all important. And, it can also depend on any special equipment that
you have on your vehicle.
Look in the following chart to ®nd the maximum trailer weight for your vehicle.
Vehicle Axle Ratio Maximum Trailer Weight *GCWR
2WD (L6 Engine)3.42 4,800 lbs.(2 177 kg) 10,000 lbs.(4 535 kg)
3.73 5,300 lbs.(2 404 kg) 10,500 lbs.(4 762 kg)
4.10 5,800 lbs.(2 631 kg) 11,000 lbs.(4 989 kg)
4WD (L6 Engine)3.42 4,700 lbs.(2 132 kg) 10,000 lbs.(4 535 kg)
3.73 5,200 lbs.(2 359 kg) 10,500 lbs.(4 762 kg)
4.10 5,700 lbs.(2 585 kg) 11,000 lbs.(4 989 kg)
2WD (V8 Engine)3.42 5,800 lbs. (2 631 kg) 11,000 lbs. (4 990 kg)
3.73 6,500 lbs. (2 948 kg) 12,500 lbs. (5 670 kg)
4WD (V8 Engine)3.42 5,600 lbs. (2 540 kg) 11,000 lbs. (4 990 kg)
3.73 6,400 lbs. (2 903 kg) 12,500 lbs. (5 670 kg)
4-58

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can not see or smell CO. It can cause
unconsciousness or death. See
Engine
Exhaust on page 2-39
. To maximize your safety
when towing a trailer:
·Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
·Keep the rear-most windows closed.
·If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
the climate control setting for maximum air
because it only recirculates the air inside
your vehicle. See
Dual Climate Control
System on page 3-20.Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connection, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
4-62

Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear, under heavy
loads or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, see
Engine Overheating on
page 5-26.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake, and then shift into PARK (P).
5. Release the regular brakes.
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{CAUTION:
It can be dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P) with
the parking brake ®rmly set. Your vehicle
can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won't move,
even when you're on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P)
with the parking brake ®rmly set.
If the transfer case on four-wheel drive
vehicles is in NEUTRAL, your vehicle will be
free to roll, even if your shift lever is in
PARK (P). So, be sure the transfer case is in a
drive gear Ð not in NEUTRAL.
See ªFour-Wheel Drive (Automatic Transfer
Case)º in the Index.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
·start your engine,
·shift into a gear, and
·release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission ¯uid (don't over®ll),
engine oil, axle lubricant, belt(s), cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you ®nd them quickly. If
you're trailering, it's a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-65

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-6
Filling Your Tank............................................5-7
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...................................................5-15
Engine Air Cleaner/Filter................................5-20
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-23
Radiator Pressure Cap..................................5-26
Engine Overheating.......................................5-26
Cooling System............................................5-28
Engine Fan Noise.........................................5-34
Power Steering Fluid.....................................5-35
Windshield Washer Fluid................................5-36Brakes........................................................5-37
Battery........................................................5-40
Jump Starting...............................................5-41
Rear Axle.......................................................5-46
Four-Wheel Drive............................................5-46
Front Axle......................................................5-47
Bulb Replacement..........................................5-48
Headlamps..................................................5-48
Taillamps and Turn Signal Lamps...................5-49
Replacement Bulbs.......................................5-50
Windshield Wiper Blade Replacement..............5-50
Tires..............................................................5-52
In¯ation - Tire Pressure.................................5-60
Tire Inspection and Rotation...........................5-61
When It Is Time for New Tires.......................5-63
Buying New Tires.........................................5-64
Uniform Tire Quality Grading..........................5-65
Wheel Alignment and Tire Balance..................5-66
Wheel Replacement......................................5-66
Tire Chains..................................................5-68
Accessory In¯ator.........................................5-68
If a Tire Goes Flat........................................5-70
Changing a Flat Tire.....................................5-71
Spare Tire...................................................5-83
Section 5 Service and Appearance Care
5-1

Service
Your dealer knows your vehicle best and wants you to
be happy with it. We hope you will go to your dealer
for all your service needs. You will get genuine GM parts
and GM-trained and supported service people.
We hope you will want to keep your GM vehicle all GM.
Genuine GM parts have one of these marks:
California Proposition 65 Warning
Most motor vehicles, including this one, contain and/or
emit chemicals known to the State of California to
cause cancer and birth defects or other reproductive
harm. Engine exhaust, many parts and systems
(including some inside the vehicle), many ¯uids, and
some component wear by-products contain and/or emit
these chemicals.
Doing Your Own Service Work
If you want to do some of your own service work, you
will want to use the proper service manual. It tells
you much more about how to service your vehicle than
this manual can. To order the proper service manual,
see
Service Publications Ordering Information on
page 7-11.
Your vehicle has an air bag system. Before attempting
to do your own service work, see
Servicing Your Air
Bag-Equipped Vehicle on page 1-59.
5-3

You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. See
Maintenance Record on page 6-17.
{CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.
·Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.
·Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the air¯ow 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
of 87 or higher. If the octane is less than 87, you may
get a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you might damage
your engine. A little pinging noise when you accelerate
or drive uphill is considered normal. This does not
indicate a problem exists or that a higher-octane fuel is
necessary. If you are using 87 octane or higher-octane
fuel and hear heavy knocking, your engine needs
service.
5-4