1999 GMC JIMMY tow

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5-19
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.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº 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 ªblowout,º 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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5-21 Removing the Spare Tire and Tools
The jacking equipment you'll need is stored along the
driver's side inner rear quarter panel. In some cases, you
may have to remove the spare tire in order to reach the
jack. Your vehicle is also equipped with work gloves
and a plastic ground mat to assist in the changing of a
flat tire.
To remove your jack cover,
pull up on the latch(es) on
the cover. Remove the
wheel blocks, jack and
wheel wrench.
The following instructions explain how to remove
the spare tire, depending on where it is mounted on
your vehicle.
NOTICE:
Never remove or restow a tire from/to a stowage
position under the vehicle while the vehicle is
supported by a jack. Always tighten the tire fully
against the underside of the vehicle when restowing.
To remove the
underbody
-mounted spare,
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.
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.

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5-26
4. Raise the vehicle by turning the jack handle
clockwise. Raise the vehicle far enough off the
ground so there is enough room for the spare tire
to fit.
5. Remove all the wheel nuts and take off the flat tire.
6. Remove any rust or dirt
from the wheel bolts,
mounting surfaces and
spare wheel.
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.

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5-27
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.
9. Lower the vehicle by turning the jack handle
counterclockwise. Lower the jack completely.

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5-33 Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will clear
the area around your front wheels. If you have a four
-wheel
drive vehicle, shift into 4HI. Then shift back and forth
between REVERSE (R) and a forward gear (or with a
manual transmission, between FIRST (1) or SECOND (2)
and REVERSE (R)), spinning the wheels as little as possible.
Release the accelerator pedal while you shift, and press
lightly on the accelerator pedal when the transmission is in
gear. By slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that may
free your vehicle. If that doesn't get you out after a few tries,
you may need to be towed out. Or, you can use your recovery
hooks if your vehicle has them. If you do need to be towed
out, see ªTowing Your Vehicleº in the Index.
Using the Recovery Hooks
Your vehicle may be equipped with recovery hooks.
The recovery hooks are provided at the front of your
vehicle. You may need to use them if you're stuck
off
-road and need to be pulled to some place where you
can continue driving.

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5-34
CAUTION:
The recovery hooks, when used, are under a lot of
force. Always pull the vehicle straight out. Never
pull on the hooks at a sideways angle. The hooks
could break off and you or others could be
injured from the chain or cable snapping back.
NOTICE:
Never use the recovery hooks to tow the vehicle.
Your vehicle could be damaged and it would not
be covered by warranty.

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6-11 Checking Engine Oil
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.

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6-13
As shown in the chart, SAE 5W-30 is best for your
vehicle. However, you can use SAE 10W
-30 if it's going
to be 0F (
-18C) or above. These numbers on an oil
container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
-50.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
ªStarburstº 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 where the temperature falls below
-20F (-29C), consider using 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
Don't add anything to your oil. Your 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 trip/city
maintenance schedule:

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 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 causes engine oil to break down slower.