cooling GMC SIERRA 1994 Owners Manual

A/C Button
Press the button marked A/C to turn your air conditioner on and off. The
A/C symbol will light on your display and air will come out of your
instrument panel vents. The fan
will automatically be set on LOW.
When you press the A/C button to turn the air conditioner off, the system
will operate in the
vent mode. When you turn the air conditioner back on,
the system will operate
in the mode that you last selectcd unless the OFF
button was pressed.
MAX Button
If you press the MAX button, the air in your vehicle will be recirculated.
With the air conditioner on,
MAX will give you maximum cooling. It can
also be used
in all modes to help keep dust out of your vchicle. When MAX
is selected, REC will light on your display.
If your air conditioner develops high system pressure, it will automatically
go into the
MAX mode and REC will light on your display. The A/C
system will remain in the MAX mode, even if you press the MAX button,
until system pressure returns
to a normal level.
Fan Control Button
This button is in the upper right corner of your system control panel. The
fan has four settings
- low, medium low, medium high and high. Press the
top of the button
“+” to increase the air flow. Press the bottom of the button
“-” to decrease the air flow. The setting you select is shown on your display
as LOW, MED LOW, MED HI or HI.
OFF Button
Press this button to turn the air conditioning/heating system off. Pressing
OFF will erase the present mode of operation from the system’s memory.
Outside air will still come out of
the heater outlet whenever the vehicle is
moving forward.
If the OFF button was pressed, you must press A/C, MAX, or one of the
BLEND buttons for the system to come back on.
Rear Window Defogger
You can tell if your vehicle has this option by looking at the rear window. If
you see lines running across the glass, you have it. These are the conductive
wire-like elements which heat your window.
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After Off-Road Driving
Remove any brush or debris that has collected on the underbody, chassis or
under the hood. These accumulations can be
a fire hazard.
After operation
in mud or sand, have the brake linings cleaned and checked.
These substances can cause glazing and uneven braking. Check the body
structure, steering, suspension, wheels, tires, and exhaust system for
damage. Also, check the fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service due to off-road use. Refer
to the Maintenance Schedule for additional information.
Driving at Night
Night driving is more dangerous than day driving. One reason is that some
drivers are likely to be impaired
- by alcohol or drugs. with night vision
problems,
or by fatigue.
Here are some tips
on night driving.
Drive defensively.
Don’t drink and drive.
a Adjust your inside rearview mirror to reduce the glare from headlights
behind you.
Since you can’t see as well, you may need to slow down and keep more
space between you and other vehicles.
Slow down, especially on higher speed roads. Your headlights can light
up only so much road ahead.
In remote areas, watch for animals.
If you’re tired, pull off the road in a safe place and rest.
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What can you do about highway hypnosis? First, be aware that it can
happen.
Then here are some tips:
0 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.
0 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.
Hill and Mountain Roads
Driving on steep hills or mountains is different from driving in flat or
rolling terrain.
If you drive regularly in steep country, or if you're planning to visit there,
here are some tips that can make your trips safer and more enjoyable. (See
"Off-Road Driving" in the Index for information about driving off-road.)
0 Keep your vehicle in good shape. Check all fluid levels and also the
brakes, tires, cooling system and transmission. These parts can work
hard
on mountain roads.
0 Know how to go down hills. The most important thing to know is this:
let your engine do some of the slowing down. Shift to a lower gear
when you go down
a steep or long hill.
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A CAUTION:
It can be dangerous to get out of your vehicle if the shift lever is
not fully in “P” (Park) with the parking brake firmly set. Your
vehicle can roll.
If’ you have left the engine running, the vehicle can move
suddenly. You or others could be injured.
To be sure your vehicle
won’t move, even when you’re on fairly level ground, use the
steps that follow.
If you have four-wheel drive and your transfer case is in “N”
(Neutral), your vehicle will be free to roll, even if your shift lever
is in
“P” (Park). So, be sure the transfer case is in a drive gear
- not in “N” (Neutral).
If you are parking on a hill, or if you’re pulling a trailer, also see
“Parking
On Hills” in the Index.
When You Are Ready to Leave After Parking on a Hill
1. Apply your regular brakes and hold the pedal down while you:
Start your engine;
Shift into a gear; and
0 Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re pulling a trailer. See
the Maintenance Schedule for more on this. Things that are especially
important in trailer operation are automatic
fluid (don’t overfill), engine oil,
axle lubricant, belts, cooling system, and brake adjustment. Each of these
is
covered in this manual, and the Index will help you find them quickly. If
you’re trailering, it’s
a good idea to review these sections before you start
your trip.
Check periodically to see that all hitch nuts and bolts are tight.
Trailer Light Wiring
See “Trailer Wiring Harness” in the Index.
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Cooling System -Gas Engines
When you decide it's
safe to lift the hood,
here's what you'll see:
A. Coolant recovery
tank
B. Engine fan(s)
C. Radiator pressure
cap
A CAUTION:
If your vehicle has air conditioning, the auxiliary electric fan
under the hood can start up even when
the engine is not running
and can injure you. Keep hands, clothing and tools away from
any underhood electric fan.
If the coolant inside the coolant recovery tank is boiling, don't do anything
else until it
cools down.
The coolant level
should be at or above
the
COLD mark. If it
isn't, you may have a
leak in the radiator
hoses, heater hoses,
radiator, water
pump
or somewhere else in
the cooling system.
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I NOTICE:
In cold weather, water can freeze and crack the engine, radiator, \
heater core and other parts. Use the recommended coolant.
When the coolant in the coolant recovery tank is at or above the COLD
mark, start your vehicle.
If the overheat warning continues, there’s one more thing you can try. You
can add the proper coolant mix directly to the radiator!, but be sure the
cooling system is cool before
you do it.
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How to Add Coolant to the Radiator
1. You can remove the radiator pressure cap when the cooling system,
including the radiator pressure cap and upper radiator hose, is no longer
hot.
Turn the pressure cap slowly to the left until it first stops. (Don’t press
down while turning the pressure cap.)
If you hear a hiss, wait for that
to stop. A hiss means there is still some
pressure left.
I
r
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A CAUTION:
If your vehicle has air conditioning, the auxiliary electric fa\
n
under the hood can start up even when the engine
is not running
and can injure you. Keep hands, clothing and tools away
from
any underhood electric fan.
If the coolant inside the coolant surge tank is boiling, don’t do anything else
until it cools down.
E The coolant level
should be slightly
above the
COLD
mark. If it isn’t, you
may have a leak in the
radiator hoses, heater
hoses, radiator, water
pump or somewhere
else
in the cooling
system.
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I NOTICE:
Engine damage from running your engine without coolant isn’t \
covered
by your warranty.
If there seems to be no leak, start the engine again. See if the fan speed
increases when idle speed
is doubled by pushing the accelerator pedal down.
If it doesn’t, your vehicle needs service. Turn off the engine.
How to Add Coolant to the Coolant Surge lank
If you haven’t found a problem yet, but the coolant level isn’t at the COLD
mark add a 50/50 mixture of clean water (preferably distilled) and a proper
antifreeze at the coolant surge tank, but be sure the cooling system,
including the coolant surge tank pressure cap, is cool before you do
it. (See
“Engine Coolant”
in the Index for more information about the proper
coolant mix.)
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..I . ... . ;. ..
Engine Fan Noise
Your 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 every day
driving conditions
the fan is spinning slower and 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 partially 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 UfluSual 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, then gently brake to a
stop well
out of the traffic lane.
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