engine GMC ACADIA 2007 Repair Manual

Hydroplaning
Hydroplaning is dangerous. So much water can
build up under the tires that they can actually ride
on the water. This can happen if the road is
wet enough and you are going fast enough.
When your vehicle is hydroplaning, it has little or
no contact with the road.
Hydroplaning does not happen often. But it can
if the tires do not have much tread or if the
pressure in one or more is low. It can happen if a
lot of water is standing on the road. If you can
see reections from trees, telephone poles,
or other vehicles, and raindrops dimple the water’s
surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds.
There just is not a hard and fast rule about
hydroplaning. The best advice is to slow down
when it is raining.
Driving Through Deep Standing Water
Notice:If you drive too quickly through deep
puddles or standing water, water can come in
through the engine’s air intake and badly
damage the engine. Never drive through water
that is slightly lower than the underbody of your
vehicle. If you cannot avoid deep puddles or
standing water, drive through them very slowly.
Driving Through Flowing Water
{CAUTION:
Flowing or rushing water creates strong
forces. If you try to drive through owing
water, as you might at a low water
crossing, your vehicle can be carried away.
As little as six inches of owing water
can carry away a smaller vehicle. If this
happens, you and other vehicle occupants
could drown. Do not ignore police warning
signs, and otherwise be very cautious
about trying to drive through owing water.
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Before Leaving on a Long Trip
Make sure you are ready. Try to be well rested.
If you must start when you are not fresh — such as
after a day’s work — do not plan to make too
many miles that rst part of the journey. Wear
comfortable clothing and shoes you can easily
drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it is ready to go. If it
needs service, have it done before starting out.
Of course, you will nd experienced and able
service experts at dealers/retailers all across
North America. They are ready and willing to help
you if needed.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?
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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 vehicle’s mirrors
and 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.
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Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in at or rolling terrain.If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that
can make your trips safer and more enjoyable.
Keep your vehicle in good shape. Check
all uid levels and also the brakes, tires,
cooling system, and transmission. These parts
can work hard on mountain roads.
{CAUTION:
If you do not shift down, the brakes could
get so hot that they would not work well.
You would then have poor braking or
even none going down a hill. You could
crash. Shift down to let the engine assist
the brakes on a steep downhill slope.
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{CAUTION:
Coasting downhill in NEUTRAL (N) or with
the ignition off is dangerous. The brakes
will have to do all the work of slowing
down. They could get so hot that they
would not work well. You would then have
poor braking or even none going down a
hill. You could crash. Always have the
engine running and your vehicle in gear
when you go downhill.
Know how to go down hills. The most
important thing to know is this: let the engine
do some of the slowing down. Shift to a
lower gear when you go down a steep or
long hill.
Know how to go uphill. You may want to shift
down to a lower gear. The lower gears help
cool the engine and transmission, and you can
climb the hill better.
Stay in your own lane when driving on
two-lane roads in hills or mountains. Do not
swing wide or cut across the center of the
road. Drive at speeds that let you stay in your
own lane.
As you go over the top of a hill, be alert.
There could be something in your lane,
like a stalled car or an accident.
You may see highway signs on mountains
that warn of special problems. Examples
are long grades, passing or no-passing zones,
a falling rocks area, or winding roads.
Be alert to these and take appropriate action.
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You can run the engine to keep warm, but be
careful.
{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 the 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 the 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.
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You will need a well-charged battery to restart the
vehicle, and possibly for signaling later on with
the 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.
If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck, you
need to spin the wheels, but you do not want
to spin the wheels too fast. The method known
as rocking can help you get out when you
are stuck, but you must use caution.
{CAUTION:
If you let your vehicle’s tires spin at high
speed, they can explode, and you or others
could be injured. And, the transmission or
other parts of the vehicle can overheat.
That could cause an engine compartment
re or other damage. When you are stuck,
spin the wheels as little as possible. Do not
spin the wheels above 35 mph (55 km/h) as
shown on the speedometer.
Notice:Spinning the wheels can destroy parts
of your vehicle as well as the tires. If you
spin the wheels too fast while shifting
the transmission back and forth, you can
destroy the transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 456.
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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.
You may also damage your vehicle; the
resulting repairs would not be covered by
your warranty. Pull a trailer only if you
have followed all the steps in this section.
Ask your dealer/retailer for advice and
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.But trailering is different than just driving your
vehicle by itself. Trailering means changes
in handling, acceleration, braking, 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.
Load-pulling components such as the engine,
transmission, rear axle, wheel assemblies and tires
are forced to work harder against the drag of
the added weight. The engine is required
to operate at relatively higher speeds and under
greater loads, generating extra heat. What’s more,
the trailer adds considerably to wind resistance,
increasing the pulling requirements.
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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. You can ask a
hitch dealer/retailer about sway controls.
Don’t tow a trailer at all during the rst
500 miles (805 km) your new vehicle is driven.
Your engine, axle or other parts could be
damaged.
Then, during the rst 500 miles (805 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.
Obey speed limit restrictions when towing a
trailer. Don’t drive faster than the maximum
posted speed for trailers, or no more than
55 mph (90 km/h), to save wear on your
vehicle’s parts.
You can tow in DRIVE (D). You may want to
shift the transmission to a lower gear selection
if the transmission shifts too often (e.g., under
heavy loads and/or hilly conditions). See
“Tow/Haul Mode” later in this section.
Three important considerations have to do with
weight:
the weight of the trailer
the weight of the trailer tongue
and the total weight on your vehicle’s tires
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Operating the vehicle in tow/haul when lightly
loaded or with no trailer at all will not cause
damage. However, there is no benet to the
selection of Tow/Haul when the vehicle is
unloaded. Such a selection when unloaded may
result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a
heavy trailer or a large or heavy load.
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. It can also depend
on any special equipment that you have on your
vehicle, and the amount of tongue weight the
vehicle can carry. See “Weight of the Trailer
Tongue” later in this section for more information.
Maximum trailer weight is calculated assuming
only the driver is in the tow vehicle and it
has all the required trailering equipment.The weight of additional optional equipment,
passengers and cargo in the tow vehicle must be
subtracted from the maximum trailer weight.
Look in the following chart to nd the maximum
trailer weight for your vehicle.
PackageMaximum
Trailer Weight*GCWR
Front-Wheel
Drive4,500 lbs
(2 041 kg)9,500 lbs
(4 309 kg)
All-Wheel Drive4,500 lbs
(2 041 kg)9,700 lbs
(4 400 kg)
*The Gross Combination Weight Rating (GCWR)
is the total allowable weight of the completely
loaded vehicle and trailer including any
passengers, cargo, equipment and conversions.
The GCWR for your vehicle should not be
exceeded.
Ask your dealer/retailer for our trailering
information or advice, or write us at our Customer
Assistance Offices. SeeCustomer Assistance
Offices on page 522for more information.
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