
I
If Steam Is Coming From Your Engine
I A CAUTION:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine
if you see or hear steam coming
from it. Just turn it
off and get everyone away
from the vehicle until it cools down. Wait until
there is no sign of steam or coolant before you
open the hood.
CAUTION: (Continued) tin
If you
keep driving when your engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool.
I NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.
If No Steam Is Coming From Your Engine
If you get the overheat warning but see or hear no
steam, the problem may not be
too serious. Sometimes
the engine can get a little too hot when
you:
0 Climb a long hill on a hot day.
0 Stop after high-speed driving.
0 Idle for long periods in traffic.
0 Tow a trailer. See “Driving on Grades” in the Index.
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Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spi.ns faster to provide
more air
to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves
fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer towing and/or high outside temperatures, the fan speed
increases as the clutch more fully engages.
So you may
hear an increase in fan noise. This
is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional
cooling is not required and the clutch disengages.
You may also hear this
fan noise when you start the engine.
It will
go away as the fan clutch partially disengages.
If a Tire Goes Flat
It’s unusual for a tire to “blow out” while you’re driving,
especially
if you maintain your tires properly. If air goes
out
of a tire, it’s much more likely to leak out slowly.
But if you should ever have
a “blowout,” here are a
few tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you’d use in
a skid. In any rear blowout, remove your foot from
the accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but
you can still steer. Gently
brake
to a stop -- well off the road if possible.
If a tire goes flat, the next part shows how to
use your
jacking equipment
to change a flat tire safely.
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Engine Oil Additives
Don’t add anything to your oil. Your GM dealer is ready
to advise if you think something should be added.
When to Change Engine Oil
If any one of these is true for you, use the short tripkity
maintenance schedule:
0
0
0
0
0
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures
are below freezing.
Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
You operate your vehicle in dusty areas or
off-road frequently.
You frequently tow a trailer.
The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and filter
every
3,000 miles (5 000 km) or 3 months -- whichever
occurs first. If
none
of them is true, use the long triphighway
maintenance schedule. Change the oil and filter
every
7,500 miles (12 500 km) or 12 months -- whichever
occurs first. Driving
a vehicle with a fully warmed
engine under highway conditions causes engine oil to
break down slower.
What to Do with Used Oil
Did you know that used engine oil contains certain
elements that may be unhealthy for your skin and could
even cause cancer? Don’t let used oil stay on your skin
for very long. Clean your skin and nails with soap and
water,
or a good hand cleaner, Wash or properly throw
away clothing or rags containing used engine oil. (See
the manufacturer’s warnings about the use and disposal
of oil products.)
Used oil can be a real threat to the environment.
If you
change your own oil, be sure to drain all free-flowing oil
from the filter before disposal. Don’t ever dispose of oil
by putting it in the trash, pouring it on the ground, into
sewers, or into streams or bodies of water. Instead,
recycle
it by taking it to a place that collects used oil. If
you have a problem properly disposing of your used oil,
ask your dealer, a service station or a local recycling
center for help.
6-18
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Refer to the Maintenance Schedule to determine when to
replace the air filter. See “Owner Checks and Services”
in
the Index.
Operating the engine with the
air cleaner off
can cause you OF others to be burned. The air
cleaner not only cleans the air,
it stops flame if
the engine backfires.
If it isn’t there, and the
engine backfires, you could be burned. Don’t
drive with it
off, and be careful working on the
engine with the air cleaner
off.
I NOTICE:
If the air cleaner is off, a backfire can cause a
damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner in place when you’re driving.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is
when the engine oil is changed.
Change both the fluid and filter every
50,000 miles
(83
000 km) if the vehicle’s CVWR is over 8,600 or
if the vehicle is mainly driven under one or more
of
these conditions:
In heavy city traffic where the outside temperature
regularly reaches
90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If your vehicle’s GVWR is not over
8,600 and you do
not use your vehicle under any
of these conditions, the
fluid and filter do
not require changing.
See “Scheduled Maintenance Services’’
in the Index.
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How to Check
Because this operation can be a little difficult, you may
choose to have this
done at your GM dealership
Service Department.
If you do it yourself, be sure to follow all the instructions
here,
or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission.
Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire. Be
sure to get an accurate reading if you check your
transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
0 When outside temperatures are above 90°F (32°C).
To get the right reading, the fluid should be at normal
operating temperature, which
is 180°F to 200 "F
(82°C to 93°C).
Checking Transmission Fluid Hot
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it's colder than 50°F ( 10°C), drive the
vehicle
in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes. Then
follow
the hot check procedures.
Checking Transmission Fluid Cold
A cold check is made after the vehicle has been sitting
for eight hours or more with the engine
off and is used
only as a reference. Let the engine run at idle for five
minutes if outside temperatures are 50°F
( 10°C) or
more. If it's colder than
50°F (lO"C), you may have
to idle the engine longer. Should the fluid level be low
during a cold check,
you must perform a hot check
before adding fluid. This will give you a more accurate
reading
of the fluid level.
0 At high speed for quite a while.
0 In heavy traffic -- especially in hot weather.
0 While pulling a trailer.
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How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you’ll need to add
some lubricant. Add enough lubricant
to raise the level
to the bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind
of lubricant to use. See “Recommended Fluids and
Lubricants”
in the Index.
C3 (3500 HD) Trucks Equipped with
Dana Rear Axle
Additional rear axle scheduled maintenance is required
on
3500 HD models equipped with Dana rear axles
when they are driven under the following conditions:
Extreme loading (at or near GVWR) or trailer
Operation above 45 mph (70 km/h) for extended
towing, and:
periods of time.
Vehicles used in any
of these conditions require the rear
axle lubricant be changed every
30,000 miles (50 OOO km).
Fluid capacity is 4.12 quarts (3.9 L).
Four-wheel Drive
Most lubricant checks in this section also apply to
four-wheel-drive vehicles. However, they have two
additional systems that need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See “Periodic Maintenance
Inspections” in the Index.
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Maintenance Schedule
-
Short Trip/City Definition -- Gasoline Engines
Follow the Short TripKity Maintenance Schedule if any
one of these conditions is true for your vehicle:
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures
are below freezing.
driving in stop-and-go traffic).
off-road frequently.
Most trips include extensive idling (such as frequent
You operate your vehicle in dusty areas or
You frequently tow a trailer.
If the vehicle is used for delivery service, police, taxi
One of the reasons you should follow this schedule if you
operate
your vehicle under any of these conditions is that
these conditions cause engine
oil to break down soonel:
Short Trip/City Intervals -- Gasoline Engines
Every
3,000 Miles (5 000 km): Engine Oil and Filter
or other commercial application.
Change (or
3 months, whichever occurs first). Chassis
Lubrication (or
3 months, whichever occurs first). Drive
Axle Service (or
3 months, whichever occurs fmt).
Short Trip/City Intervals -- Gasoline Engines
Every 6,000 Miles (10
000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Shields and
Underhood Insulation Inspection (GVWR above
8,500 lbs. only). Front Wheel Bearing Repack (2WD
only) (or at each brake relining, whichever occurs first).
Every 30,000 Miles (50 000 km): Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (vehicles over
8600 GVWR or
driven under severe conditions only).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel Tank, Cap and Lines
Inspection. Exhaust Gas Recirculation System
Inspection. Evaporative Control System Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete maintenance schedule
on the following pages.
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Maintenance Schedule
Follow this maintenance schedule only if none of the
conditions from the Short Trip/City Maintenance
Schedule is true.
Da not use this schedule if the vehicle
is used for trailer towing, driven in a dusty area or used
off paved roads. Use the Short Trip/City schedule for
these conditions.
Driving a vehicle with afully warmed engine under
highway conditions causes engine
oil to break
down slower:
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every
12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Service. Tire Rotation.
Underhood Insulation Inspection (GVWR above
8,500 lbs. only).
Every 15,000 Miles (25 OOO km): Shields and
I
1 Long Trip/Highway Intervals -- Gasoline Engines ~~~ ~
~ ~~
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Front Wheel Bearing Repack
(2WD only)
(or at each brake relining, whichever occurs fiist).
Transmission Service (vehicles over
8600 GVWR or
driven under severe conditions only).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel
Tank, Cap and Lines
Inspection. Exhaust Gas Recirculation System
Inspection. Evaporative Control System Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
Every 50,000 Miles (83 000 km): Automatic
These intervals only summarize maintenance services.
Be sure to
follow the complete maintenance schedule
on the following pages.
7-6
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