1994 CHEVROLET SUBURBAN cooling

6. Start the engine
and let it run until
you can feel the
upper radiator
hose getting hot.
Watch
out for the
engine fan(s).
By this time the coolant level inside the radiator filler neck may be
lower.
If the level is lower, add more of the proper mix 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 pressure cap
line up
like this.
Cooling System -Diesel Engines
When you decide it's
safe
to lift the hood,
here's what
you'll see:
A
A. Coolant surge
tank pressure cap
B. Engine fan(s)
C. Radiator
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If the coolant inside the coolant surge 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.
NOTICE:
Engine damage from running your engine without coolant isn't
covered by your warranty.
If there seems to be no leak, start the engifie 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.
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How to Add Coolant to the Coolant Surge Tank
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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NOTICE:
In cold weather, water can freeze and crack the engine, radiat\
or,
heater core and other parts.
So use the recommended coolant.
1. You can remove the coolant surge tank pressure cap when the cooling
system, including the coolant surge tank pressure cap and upper
radiator
hose, is no longer hot.
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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 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, 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 section shows how to use your jacking equipment
to change a flat tire safely.
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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’ll need
to add some lubricant.
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 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.
The proper coolant for your vehicle will:
Give freezing protection down to -20°F (-29”C), or -34°F (-37°C) in
Give boiling protection up to 258°F (1 25°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Canada
and for vehicles with the cold climate option.
Let the warning lights and gages work as they should.
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What to Use
use a mixture of one-half clean water (preferably distilled) and one-half
antifreeze that meets
“GM Specification 6038-M,” which won’t damage
aluminum
parts. You can also use a recycled coolant conforming to “GM
Specification 6038-M” with a complete coolant flush and refill. If you use
this mixture, you don’t need
to add anything else.
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.
Some conditions, such as air trapped in the cooling system, can affect the
coolant level in the radiator. Check the coolant level when the engine is cold
and follow the steps under “Adding Coolant” for
the proper way to add
coolant.
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.
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Surge Tank Pressure Cap- Diesel Engines
The surge tank
pressure cap must be
tightly installed with
the arrows
on the cap
lined up with the top
tube
of the coolant
surge tank.
NOTICE:
Your surge tank pressure cap 1s a unique 15 psi (105 kPa)
pressure-type cap for use with surge tank cooling systems only.
It 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 top tube
of the coolant surge tank.
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.
Power Steering Fluid
I NOTICE:
Always turn the engine off before checking or adding power
steering
fluid. The power steering pump cap is close to the fan
and other moving parts.
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