1999 GMC SONOMA Capacity

2-66 Check Gages Light
If this light comes on
and stays on while you
are driving, check your
coolant temperature
and engine oil pressure
gages to see if they are
in the warning zones.
Fuel Gage
When the ignition is on, the
fuel gage tells you about
how much fuel you
have remaining.Here are four things that some owners ask about.
None of these show a problem with your fuel gage:

At the gas station, the gas pump shuts off before the
gage reads F (Full).

It takes a little more or less fuel to fill up than the gage
indicated. For example, the gage may have indicated
the tank was half full, but it actually took a little more
or less than half the tank's capacity to fill the tank.

The gage moves a little when you turn a corner
or speed up.

The gage doesn't go back to E (Empty) when you
turn off the ignition.
Low Fuel Light
This light comes on briefly
when you start your engine.
This light comes on when the fuel tank is low on fuel.
To turn it off, add fuel to the fuel tank. See ªFuelº
in the Index.

4-40
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmission fluid level before driving the vehicle.
When towing your vehicle, turn the ignition to OFF.
To prevent your battery from draining while towing,
remove the RDO BATT fuse from the instrument panel
fuse block. Be sure to replace the fuse when you reach
your destination. See ªFuses and Circuit Breakersº in
the Index.
Be sure to use the proper towing equipment designed for
recreational vehicle towing. Follow the instructions for
the towing equipment.Loading Your Vehicle
The Certification/Tire label is found on the driver's door
edge, above the door latch. The label shows the size of
your original tires and the inflation pressures needed to
obtain the gross weight capacity of your vehicle. This is
called the Gross Vehicle Weight Rating (GVWR). The
GVWR includes the weight of the vehicle, all occupants,
fuel, cargo and trailer tongue weight, if pulling a trailer.

4-42
CAUTION:
Things you put inside your vehicle can strike
and injure people in a sudden stop or turn, or
in a crash.

Put things in the cargo area of your vehicle.
Try to spread the weight evenly.

Never stack heavier things, like suitcases,
inside the vehicle so that some of them are
above the tops of the seats.

Don't leave an unsecured child restraint in
your vehicle.

When you carry something inside the
vehicle, secure it whenever you can.
There's also important loading information for off-road
driving in this manual. See ªLoading Your Vehicle for
Off
-Road Drivingº in the Index.
Payload
The payload capacity is shown on the Certification/Tire
label. This is the maximum load capacity that your
vehicle can carry. If you are using ethanol fuel the
maximum payload should not exceed 1000 lbs (454 kg).
Be sure to include the weight of the occupants as part of
your load. If you added any accessories or equipment
after your vehicle left the factory, remember to subtract
the weight of these things from the payload. Your dealer
can help you with this.
2-Tiered Loading
By positioning four 2, x 6, wooden planks across the
width of the pickup box, you can create an upper load
platform. The planks must be inserted in the pickup box
depressions. The length of the planks must allow for at
least a 3/4 inch (2 cm) bearing surface on each end of
the plank.
When using this upper load platform, be sure the load is
securely tied down to prevent it from shifting. The
load's center of gravity should be positioned in a zone
over the rear axle. The zone is located in the area
between the front of each wheel well and the rear of
each wheel well. The center of gravity height must not
extend above the top of the pickup box flareboard.

4-46
Towing a Trailer
CAUTION:
If you don't 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.
Pull a trailer only if you have followed all the
steps in this section. Ask your dealer for advice
and information about towing a trailer with
your vehicle.
NOTICE:
Pulling a trailer improperly can damage your
vehicle and result in costly repairs not covered by
your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer
with your vehicle.
Your vehicle may be able to tow a trailer. To identify
what the vehicle trailering capacity is for your vehicle,
you should read the information in ªWeight of the
Trailerº that appears later in this section.
If yours was built with trailering options, as many are,
it's ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in 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.

4-48
The following chart shows how much your trailer can
weigh, based upon your vehicle model and options.
VehicleAxle
Ratio Max. Trailer Wt.
2WD 2.2L
L4 Engine*#3.73
4.102,000 lbs. (908 kg)
2,300 lbs. (1 044 kg)
2WD ªVORTECº
4300 V6,
Auto. Trans.*3.08
3.425,400 lbs. (2 451 kg)
6,400 lbs. (2 905 kg)
2WD ªVORTECº
4300 V6,
Man. Trans.*3.08 4,200 lbs. (1 906 kg)
4WD ªVORTECº
4300 V6
Auto. Trans.3.08
3.42
3.734,900 lbs. (2 224 kg)
5,900 lbs. (2 678 kg)
5,900 lbs. (2 678 kg)
4WD ªVORTECº
4300 V6
Man. Trans.3.08
3.42
3.733,900 lbs. (1 770 kg)
4,400 lbs. (1 997 kg)
4,900 lbs. (2 224 kg)
* If your vehicle is equipped with RPO V4A
(Xtreme
Sport Appearance Package), your vehicle
was neither intended nor designed to tow a trailer. For
more information on RPO codes, see ªService Parts
Identification Labelº in the Index.# If your vehicle is equipped with a code 5 engine
you must use regular unleaded gasoline rated at
87 octane or higher when towing.
Optional body styles, equipment, passengers or cargo
will reduce trailer rating.
Maximum trailer weight is calculated assuming the
driver and one passenger are 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. The weight of the trailer tongue also
affects trailering capacity. See ªWeight of the Trailer
Tongueº later in this section.
You can ask your dealer for our trailering information or
advice, or you can write us at the address listed in your
Warranty and Owner Assistance Information Booklet.
In Canada, write to:
General Motors of Canada Limited
Customer Communication Centre
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7

4-49 Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important
weight to measure because it affects the total or gross
weight of your vehicle. The Gross Vehicle Weight
(GVW) includes the curb weight of the vehicle, any
cargo you may carry in it, and the people who will be
riding in the vehicle. And if you will tow a trailer, you
must add the tongue load to the GVW because your
vehicle will be carrying that weight, too. See ªLoading
Your Vehicleº in the Index for more information about
your vehicle's maximum load capacity.
If you're using a weight-carrying hitch, the trailer
tongue (A) should weigh 10 percent of the total loaded
trailer weight (B). If you're using a weight
-distributing
hitch, the trailer tongue (A) should weigh 12 percent of
the total loaded trailer weight (B).
After you've loaded your trailer, weigh the trailer and
then the tongue, separately, to see if the weights are
proper. If they aren't, you may be able to get them right
simply by moving some items around in the trailer.
Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the upper
limit for cold tires. You'll find these numbers on the
Certification label at the rear edge of the driver's door
edge, above the door latch, or see ªTire Loadingº in
the Index. Then be sure you don't go over the GVW
limit for your vehicle, including the weight of the
trailer tongue.

6-6
E-85 has less energy per gallon than gasoline, so you'll
need to refill your fuel tank more often when using E
-85
than when you're using gasoline. Use regular gasoline
when pulling a trailer. For payload capacity with ethanol
fuel see ªLoading Your Vehicleº in the Index.
NOTICE:
Some additives are not compatible with E-85 fuel
and may harm your fuel system. Damage caused
by additives may not be covered by your new
vehicle warranty. Don't use additives
with E
-85 fuel.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use it. It can corrode
metal parts in your fuel system and also damage
plastic and rubber parts. That damage wouldn't
be covered under your warranty.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard to
find. Never use leaded gasoline or any other fuel not
recommended in the previous text on fuel. Costly repairs
caused by use of improper fuel wouldn't be covered by
your warranty.
To check on fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you'll be driving.
You can also write us at the following address for
advice. Just tell us where you're going and give your
Vehicle Identification Number (VIN).
General Motors Overseas Distribution Corporation
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7

6-14
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'll need
to add at least one quart of oil. But you must use the
right kind. This part explains what kind of oil to use. For
crankcase capacity, see ªCapacities and Specificationsº
in the Index.
NOTICE:
Don't 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.
Be sure to fill it enough to put the level somewhere in
the proper operating range. Push the dipstick all the way
back in when you're through.