2008 CHEVROLET SUBURBAN engine

Hot Check Procedure
Use this procedure to check the transmission uid level
when the transmission uid temperature is between
160°F and 200°F (71°C and 93°C).
The hot check is the most accurate method to check the
uid level. The hot check should be performed at the rst
opportunity in order to verify the cold check. The uid
level rises as uid temperature increases, so it is
important to ensure the transmission temperature is
within range.
1. Locate the transmission dipstick at the rear of the
engine compartment, on the passenger side of the
vehicle.
The dipstick handle has
this graphic. SeeEngine
Compartment Overview
on page 5-16for more
information.
2. Flip the handle up, and then pull out the dipstick
and wipe it with a clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way,
wait three seconds, and then pull it back out again.4. Check both sides of the dipstick, and read the lower
level. Repeat the check procedure to verify the
reading.
5. Safe operating level is within the HOT cross hatch
band on the dipstick. If the uid level is not within
the HOT band, and the transmission temperature is
between 160°F and 200°F (71°C and 93°C), add
or drain uid as necessary to bring the level into
the HOT band. If the uid level is low, add only
enough uid to bring the level into the HOT band.
It does not take much uid, generally less than
one pint (0.5L). Do not overll.
6. If the uid level is in the acceptable range, push the
dipstick back in all the way, then ip the handle
down to lock the dipstick in place.
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Consistency of Readings
Always check the uid level at least twice using the
procedures described. Consistency (repeatable readings)
is important to maintaining proper uid level. If uid is
added, it may take 15 minutes or longer to obtain an
accurate reading because of residual uid draining down
the dipstick tube. If inconsistent readings persist, check
the transmission breather to be sure it is clean and not
clogged. If readings are still inconsistent, contact your
dealer/retailer.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst, 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, seeEngine Overheating
on page 5-34.A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as they
should.
Notice:Using coolant other than DEX-COOL
®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at the rst maintenance
service after each 30,000 miles (50 000 km) or
24 months, whichever occurs rst. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant
in the vehicle.
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What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL®coolant which will not damage
aluminum parts. If you use this coolant mixture, you do
not need to add anything else.
{CAUTION:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but
would not get the overheat warning. The
engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:If an improper coolant mixture is used,
the engine could overheat and be badly damaged.
The repair cost would not be covered by the vehicle
warranty. Too much water in the mixture 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/retailer check your cooling system.
Notice:If extra inhibitors and/or additives are used
in the vehicle’s cooling system, the vehicle could
be damaged. Use only the proper mixture of
the engine coolant listed in this manual for the
cooling system. SeeRecommended Fluids and
Lubricants on page 6-13for more information.
5-32

Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger’s side of the vehicle.
SeeEngine Compartment Overview on page 5-16
for more information on location.
{CAUTION:
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap — even a little — when the engine and
radiator are hot.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the FULL
COLD mark.
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Adding Coolant
If more coolant is needed, add the proper DEX-COOL®
coolant mixture at the surge tank, but only when the
engine is cool.
{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. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight and fully seated.
Coolant Surge Tank Pressure Cap
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-16for more
information on location.
Engine Overheating
There is a coolant temperature gage on your vehicle’s
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-43.
In addition, ENGINE OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE ENGINE, and a ENGINE
POWER IS REDUCED message comes on in the Driver
Information Center (DIC) on the instrument panel.
SeeDIC Warnings and Messages on page 3-59.
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If Steam Is Coming From Your Engine
{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. 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.
If you keep driving when the vehicles engine
is overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of
the vehicle until the engine is cool.
SeeOverheated Engine Protection Operating
Mode on page 5-36for information on driving
to a safe place in an emergency.Notice:If the engine catches re while driving with
no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by
the vehicle warranty. SeeOverheated Engine
Protection Operating Mode on page 5-36for
information on driving to a safe place in an
emergency.
If No Steam Is Coming From Your
Engine
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message, along
with a low coolant condition, can indicate a serious
problem.
If you get an engine 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:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-49.
5-35

If you get the ENGINE OVERHEATED STOP ENGINE
or the ENGINE OVERHEATED IDLE ENGINE message
with no sign of steam, try this for a minute or so:
1. If the vehicle has an air conditioner and it is on,
turn it off.
2. Turn on the heater to the highest temperature and
at the highest fan speed and open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle immediately.
If there is still no sign of steam and your vehicle has an
engine-driven cooling fan, push down the accelerator
until the engine speed is about twice as fast as normal
idle speed for at least ve minutes while parked.
If there is still no sign of steam and your vehicle has an
electric cooling fan, idle the engine for ve minutes
while parked.If you still have the warning, turn off the engine and get
everyone out of the vehicle until it cools down. Also,
see “Overheated Engine Protection Operating Mode”
later in this section.
You might decide not to lift the hood but to get service
help right away.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
ENGINE POWER IS REDUCED message is displayed,
an overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle
to be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil
and reset the oil life system. SeeEngine Oil
on page 5-17.
5-36

Cooling System
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan(s){CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing, and tools away
from any underhood electric fan.
If the coolant inside the coolant surge tank is boiling,
do not do anything else until it cools down. If possible,
the vehicle should be parked on a level surface.
Check the coolant level after the system cools down.
Some amount of coolant may be lost due to overheating.
5.3L Engine (4.8L, 6.0L and 6.2L Similar)
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