tow GMC SONOMA 2004 Service Manual

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.
When to Add Engine Oil
If the oil is at or below the ADD line, then you will need
to add at least one quart of oil. But you must use the
right kind. This section explains what kind of oil to use.
For engine oil crankcase capacity, seeCapacities
and Specications on page 5-101.
Notice:Do not add too much oil. If your engine has
so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, your engine could be damaged.SeeEngine Compartment
Overview on page 5-12for
the location of the
engine oil fill cap.
Be sure to add enough oil to put the level somewhere in
the proper operating range. Push the dipstick all the
way back in when you are through.
What Kind of Engine Oil to Use
Look for two things:
•GM6094M
Your vehicle’s engine requires oil meeting GM
Standard GM6094M. You should look for and use
only an oil that meets GM Standard GM6094M.
5-14

Notice:Use only engine oil identied as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certied For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench
®oil meets all the requirements for
your vehicle.
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 starburst symbol that meet GM Standard
GM6094M are all you will need for good performance
and engine protection.
When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:
•Most trips are less than 5 miles (8 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 frequently tow a trailer or use a carrier on top
of your vehicle.
•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 trip/highway
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 will cause engine oil to
break down slower.
5-16

{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 backres. If it is not
there and the engine backres, 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 backre 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 and Change the
Automatic Transmission Fluid
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 15,000 miles
(25 000 km) 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 you do not use your vehicle under any of these
conditions, change the fluid and filter every 50,000 miles
(83 000 km).
SeePart A: Scheduled Maintenance Services on
page 6-4.
5-19

Checking the Automatic Transmission
Fluid Level
Prepare your vehicle as follows:
•Park your vehicle on a level place. Keep the engine
running.
•With the parking brake applied, place the shift lever
in PARK (P).
•With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).
•Let the engine run at idle for three minutes or more.Then, without shutting off the engine, follow
these steps:
The transmission dipstick
handle has this symbol
on it.
The transmission dipstick is located near the center of
the engine compartment. SeeEngine Compartment
Overview on page 5-12for more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. To get an accurate reading, when checking the fluid
level, keep the tip of the dipstick down to avoid the
fluid traveling up the dipstick.
5-21

If No Steam Is Coming From Your
Engine
If you get an engine 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:
•Climb a long hill on a hot day.
•Stop after high-speed driving.
•Idle for long periods in traffic.
•Tow a trailer. See “Driving on Grades” under
Towing a Trailer on page 4-55.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL
while stopped. If it is safe to do so, pull off the
road, shift to PARK (P) or NEUTRAL and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there’s still no sign of steam, idle the engine for three
minutes while you’re parked. Push down the accelerator
until the engine speed is about twice as fast as
normal idle speed for at least three minutes while you’re
parked. If you still have the warning,turn off the
engine and get everyone out of the vehicleuntil it
cools down.
You may decide not to lift the hood but to get service
help right away.
5-27

Engine Fan Noise
This vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not engaged. This improves fuel
economy and reduces fan noise. Under heavy vehicle
loading, trailer towing and/or high outside temperatures,
the fan speed increases when the clutch 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 disengages.
Power Steering Fluid
The power steering reservoir is located near the front of
the engine compartment on the driver’s side of the
vehicle.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering fluid
unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired. SeeEngine Compartment Overview
on page 5-12for reservoir location.
5-35

After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the
Certification/Tire label or the Tire and Loading
Information label. Make certain that all wheel nuts are
properly tightened. See “Wheel Nut Torque” under
Capacities and Specications on page 5-101.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle.
In an emergency, you can use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if you need to, to
get all the rust or dirt off. See “Changing a Flat
Tire” in the Index.
When It Is Time for New Tires
One way to tell when it’s
time for new tires is to
check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of tread
remaining. Some
commercial truck tires may
not have treadwear
indicators.
You need a new tire if any of the following statements
are true:
•You can see the indicators at three or more places
around the tire.
•You can see cord or fabric showing through the
tire’s rubber.
•The tread or sidewall is cracked, cut or snagged
deep enough to show cord or fabric.
•The tire has a bump, bulge or split.
•The tire has a puncture, cut or other damage that
can’t be repaired well because of the size or
location of the damage.
5-69

Tire Chains
{CAUTION:
Don’t use tire chains. There’s not enough
clearance. Tire chains used on a vehicle without
the proper amount of clearance can cause
damage to the brakes, suspension or other
vehicle parts. The area damaged by the tire
chains could cause you to lose control of your
vehicle and you or others may be injured in a
crash. Use another type of traction device only
if its manufacturer recommends it for use on
your vehicle and tire size combination and road
conditions. Follow that manufacturer’s
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your wheels. If you do nd traction devices
that will t, install them on the rear tires.
If a Tire Goes Flat
It’s unusual for a tire to “blowout” 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.
5-74

Notice:If you remove or restow a tire from/to the
storage position under the vehicle when it is
supported by a jack, you could damage the tire
and/or your vehicle. Always remove or restow a tire
when the vehicle is on the ground.
3. Insert the chisel end of
the wheel wrench, on
an angle, into the
hole in the rear
bumper.
Be sure the chisel end of the wheel wrench
connects into the hoist shaft.
4. Turn the wheel wrench counterclockwise to lower
the spare tire. Keep turning the wheel wrench until
the spare tire can be pulled out from under the
vehicle.
5. When the tire has been completely lowered, tilt the
retainer at the end of the cable and pull it through
the wheel opening.6. Pull the tire out from under the vehicle.
If your vehicle is equipped with a compact spare
tire, it is stowed underneath the rear of your vehicle.
SeeCompact Spare Tire on page 5-85.
Notice:If you drive away before the spare tire or
secondary latch system cable has been reinstalled,
you could damage your vehicle. Always reinstall
this cable before driving your vehicle.
7. Put the spare tire near the flat tire.
The tools you’ll be using include the jack (A) and wheel
wrench (B). Your vehicle may also have an optional
hub cap removal tool.
5-77

{CAUTION:
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
the places where the wheel attaches to the
vehicle. In an emergency, you can use a cloth
or a paper towel to do this; but be sure to use
a scraper or wire brush later, if you need to, to
get all the rust or dirt off.
{CAUTION:
Never use oil or grease on studs or nuts. If
you do, the nuts might come loose. Your wheel
could fall off, causing a serious accident.7. Place the spare on the wheel mounting surface.
8. Put the nuts on by
hand. Make sure the
cone-shaped end
is toward the wheel.
Tighten each nut by hand until the wheel is held
against the hub. If a nut can’t be turned by
hand, use the wheel wrench and see your dealer
as soon as possible.
5-81