1998 GMC ENVOY cooling

When you decide it's safe to lift the hood, here's what
you'
I I see:
If the coolant inside the coolant recovery tank is boiling,
don't do anything else
until it cools down.
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Fan
c.
I
The coolant level should be at least up to the
ADD 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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1 h CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don’t touch them.
If you
do, you can be burned.
Don’t run the engine if there is a leak.
If you run
the engine,
it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE: I
Engine damage from running your engine
without coolant isn’t covered by your
1 warranty.
If there seems to be no leak, start the engine again. See
if the engine cooling 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
If you haven’t found a problem yet, but the coolant level
isn’t
at the ADD mark, add a 50/50 mixture of clean
brater (preferably distilled) and DEX-COOL@ engine
coolant at the coolant recovery tank. (See “Engine
Coolant”
in the Index for more information.)
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 mixture will. Your vehicle’s coolant
warning system is set for the proper coolant
mixture. With plain water
or the wrong mixture,
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 mixture of clean water and
DEX-COOL@ coolant.
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NOTICE:
In cold weather, water can freeze and crack the
engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
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 the
ADD r&ark, start your vehicle.
If the overheat warning continues, there’s one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling system is cool before you do
it.
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CAC JON:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap
-- even a little -- they can come out
at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to
cool if you ever have to
turn the pressure cap.
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How to Add Coolant to the Radiator
2. Then keep turning the pressure cap, but now push
down as you
turn it. Remove the pressure cap.
I. 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 counterclockwise
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.
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.. ..
6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
filler neck may be lower.
If the level is lower, add
more of
the proper DEX-COOL@ coolant mixture
through the filler neck until the level reaches the
base of the filler neck.
8. Then replace the pressure cap. At any time during
this procedure
if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the
arrows on the pressure
cap line up like this.
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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 “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, 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
iacking equipment to change
a flat tire safely. u Y a. c
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Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change
it. See
”Scheduled Maintenance Services”
in the Index.
How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you may need to add some lubricant. When
the differential is cold, add enough lubricant to
raise the level to
1/2 inch (12 mm) below the filler
plug hole.
When the differential
is at operating temperature
(warm), add enough lubricant to raise the level
to the
bottom
of 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 s stem in your vehicle is filled with
DEX-COOL J 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.
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