1997 GMC SIERRA engine overheat

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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If you get the overheat warning with no sign of steam,
try this for a minute or
so:
1. If you have an air conditioner, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window
as necessary.
3. If you’re in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- AUTOMATIC OVERDRIVE (@)
for automatic transmissions.
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, push the accelerator until
the engine speed is about twice as fast as normal idle
speed. Bring the engine speed back to normal idle speed
after two or three minutes. Now see if the warning stops.
But then, if
you still have the warning, turn oflthe
engine and get everyone out
of the vehicle until it
cools down.
Cooling System -- Gasoline Engines
When you decide it’s safe to lift the hood, here’s what
you’ll see:
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Fan(s)
You may decide
not to lift the hood but to get service
help right away.
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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
Recovery
Tank -- Gasoline Engines
If you haven’t found a problem yet, but the coolant level
isn’t at or above the COLD mark, add a
50/50 mixture of
clean water (preferably distilled) and DEX-COOL@
(silicate-free) antifreeze at the coolant recovery tank. (See
“Engine Coolant’’
in the Index for more information.)
I
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mix
will. Your vehicle’s coolant warning
system is set for the proper coolant mix.
CAUTION: (Continued) With plain water
or the wrong mix, your engine
could get too hot but you wouldn’t get the
overheat warning. Your engine could catch fire
and you or others could be burned. Use a
50/50
mix of clean water and DEX-COOL@coolant.
I NOTICE:
r
~~
In cold weather, water can freeze and crack the
engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mix.
5-15
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I A CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and
it will burn if the engine parts are hot
enough. Don’t spill coolant on
a hot engine.
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
cool before
you do it.
is
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C
E
I
F
Chassis Cab Models
A. Nut
B. Retainer
C. Jack Handle
Extension
D. Jack Handle Extension
E. Wheel Wrench
E Jack and Tool
Storage Box
G. Ratchet
H. Jack Handle
I. Tool Retainer
J. Jack
If You’re Stuck: In Sand, Mud,
Ice or Snow
What you don’t want to do when your vehicle is stuck is
to spin your wheels too fast. The method known
as
“rocking” can help you get out when you’re stuck, but
you must use caution.
’ A CAUTION: I I
If you let your tires spin at high speed, they can
explode, and you or others could be injured.
And, the transmission or other parts
of the
vehicle can overheat. That could cause an engine
compartment fire or other damage. When you’re
stuck, spin the wheels
as little as possible. Don’t
spin the wheels above
35 mph (55 kmlh) as shown
on the speedometer.
5-34
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If the differential is at operating temperature (warm),
add enough lubricant to raise the level to the bottom of
the filler plug hole.
If the differential is cold, add enough lubricant to raise
the level to 1/2 inch (12 mm) below 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.
Engine Coolant
The cooling system in your vehicle is filled with
new DEX-COOL@ engine coolant. This coolant is
designed to remain in your vehicle for
5 years or
150,000 miles (240
000 km), whichever occurs first,
if
you add only DEX-COOL@ extended life coolant.
The following explains your cooling system and how to
add coolant when
it is low. If you have a problem with
engine overheating, see “Engine Overheating” in
the Index.
A 50/50 mixture of water and the proper coolant for
your vehicle will:
0 Give freezing protection down to -34°F (-37°C).
0 Give boiling protection up to 265 “F (1 29°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
0 Let the warning gages work as they should.
NOTICE:
When adding coolant, it is important that you use
only
DEX-COOL@(silicate-free) coolant.
If coolant other than DEX-COOL@ is added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX-COOL@ is not
covered by your new vehicle warranty.
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What to Use
Use a mixture of one-half clean water (preferably
distilled) and one-half
DEX-COOL’ coolant which
won’t damage aluminum parts.
If you use this mixture,
you don’t need to add anything else.
A CAUTION:
Adding only plain water to your cooling system
can
be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant
mix will. Your vehicle’s coolant warning
system is set for the proper coolant
mix. With
plain water or the wrong
mix, your engine could
get too hot but you wouldn’t get the overheat
warning. Your engine could catch fire and you or
others could be burned. Use a
50/50 mix of clean
water and
DEX-COOL@ coolant.
NOTICE:
If you use an improper coolant mix, your engine
could overheat and be badly damaged. The
repair cost wouldn’t be covered
by your
warranty. Too much water in the mix can freeze
and crack the engine, radiator, heater core and
other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don’t have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.
6-30
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Radiator Pressure Cap
(Gasoline Engine)
The radiator pressure cap must be tightly installed with
the arrows
on the cap lined up with the overflow tube on
the radiator filler neck.
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
pressure-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating. Be sure the arrows on the cap line up with the overflow tube on the radiator
filler neck.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow
of coolant through the radiator until the coolant
reaches a preset temperature.
When you replace your thermostat, an
AC@ thermostat
is recommended.
6-32
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