Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic. This is
a mistake. Your brakes may not have time to cool
between hard stops. Your brakes will wear out much
faster if you do a lot of heavy braking. If you keep pace
with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking.
That means better braking and longer brake life.
If your engine ever stops while you are driving, brake
normally but do not pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
Hydraulic Brake Systems
If your engine stops running, or if your primary brake
system stops working, your vehicle has a reserve power
assist system to help you slow down. Just slowly and
steadily apply the brake pedal until you can safely get off
the road. The pedal will seem harder to push down.
Do not pump the pedal; the system will not work well or
at all that way.You may find that the steering wheel seems hard to turn
when you are turning and braking at the same time.
Also, the primary brake warning light may come on and
the warning tone may sound. This is normal because
the main hydraulic brake system and power steering
both use the power steering pump. If this ever happens,
let up on the brake pedal a little. When you let up on
the brake pedal in that situation, it lets the steering get a
little more help from the pump.
Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test is going on. This is normal.
If there is a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-34.
4-6
Before changing lanes, check your mirrors. Then use
your turn signal.
Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to
move slightly slower at night.
When you want to leave the freeway, move to the
proper lane well in advance. If you miss your exit, do
not, under any circumstances, stop and back up. Drive
on to the next exit.
The exit ramp can be curved, sometimes quite
sharply. The exit speed for cars — but not larger
vehicles — is usually posted. You should go
more slowly.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are
going slower than you actually are.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.
When you drive the vehicle for a long distance, 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.
4-23
{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 if any 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 (or batteries) charged. You will
need a well-charged battery (or batteries) to restart the
vehicle, and possibly for signaling later on with your
headlamps. Let the heater run for a while.
If you have a diesel engine, you may have to run it at a
higher speed to get enough heat.
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.
4-29
Engine Oil (Gasoline Engine)
If the low oil light appears
on the instrument cluster, it
means you need to
check your engine oil level
right away. For more
information, seeLow Oil
Level Light on page 3-38.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It is a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.The engine oil dipstick is
located in the engine
compartment on the
driver’s side of the vehicle.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-26
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the API service symbol are all you will need for
good performance and engine protection.
Engine Oil Life System
(Gasoline Engine)
When to Change Engine Oil
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based
on engine revolutions and engine temperature, and
not on mileage. Based on driving conditions, the mileage
at which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A change engine oil light will come on.
SeeChange Engine Oil Light on page 3-38.
Change your oil as soon as possible within the
next 600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for
over a year. However, your engine oil and filter must be
changed at least once a year and at this time the
system must be reset. Your dealer has GM-trained
service people who will perform this work using genuine
GM parts and reset the system. It is also important to
check your oil regularly and keep it at the proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.
5-29
Engine Oil Life System
(DURAMAX
®Diesel)
When to Change Engine Oil
If your vehicle has the Engine Oil Life System, it has a
computer system that lets you know when to change
the engine oil and filter. This is based on injection timing,
engine load and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A change engine oil light will come on.
SeeChange Engine Oil Light on page 3-38.
Change your oil as soon as possible within the next
600 miles (1 000 km) or 30 hours of engine operation,
whichever occurs first. It is possible that, if you are
driving under the best conditions, the oil life system may
not indicate that an oil change is necessary for over a
year. However, your engine oil and filter must be
changed at least once a year and at this time the system
must be reset. Your dealer has GM-trained service
people who will perform this work using genuine
GM parts and reset the system. It is also important to
check your oil regularly and keep it at the proper level.If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km), or 150 hours
of engine operation, whichever occurs first, since
your last oil change. Remember to reset the oil life
system whenever the oil is changed.How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
your engine oil and filter based on vehicle use. Anytime
your oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change your oil prior to a change engine oil
light being turned on, reset the system.
To reset the Engine Oil Life System, do the following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal slowly
three times within 10 seconds.
If the change engine oil light flashes for five seconds,
the system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the Engine Oil Life System has
not reset. Repeat the procedure.
5-31
How to Inspect the Engine
Air Cleaner/Filter
Locate the filter change indicator. When the change
indicator turns black or is in the red/orange change area,
replace the filter and reset the indicator.
To inspect the engine air cleaner/filter, remove the filter
from the vehicle and lightly shake the filter to release
loose dust and dirt. If the filter remains caked with dirt,
a new filter is required.
{CAUTION:
Operating the engine with the air cleaner/ lter
off can cause you or others to be burned.
The air cleaner not only cleans the air; it helps
to stop ame if the engine back res. If it is
not there and the engine back res, you could
be burned. Do not drive with it off, and be
careful working on the engine with the air
cleaner/ lter off.
Notice:If the air cleaner/ lter is off, a back re can
cause a damaging engine re. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/ lter in place when you
are driving.
Automatic Transmission Fluid
When to Check
A good time to check your automatic transmission fluid
level is when the engine oil is checked. See your Allison
Automatic Transmission Operator’s Manual to find out
when to change your transmission fluid and filters.
How to Check and What to Use
The Allison Automatic Transmission Operator’s Manual
that came with the vehicle shows how to check the
automatic transmission fluid and what fluid to use.
Automatic Transmission External Filter
Your automatic transmission filter requires periodic
replacement.
Consult the Allison Automatic Transmission Operator’s
Manual that came with the vehicle for proper change
intervals.
5-34
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice:If you use the proper coolant, you do not
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
Checking Coolant
The coolant surge tank is located in the engine
compartment on the driver’s side of the vehicle.
{CAUTION:
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap — even a little — when the engine and
radiator are hot.
The vehicle must be parked on a level surface.
When your engine is cold, the coolant level should be
at the FULL COLD mark or higher.
If the low coolant warning
light comes on in the
instrument panel cluster
and stays on, it means you
are low on engine coolant.
SeeLow Coolant Warning Light on page 3-35for further
information.
5-37