2008 GMC SIERRA engine

California Fuel
If your vehicle is certied to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specications. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, your vehicle will operate
satisfactorily on fuels meeting federal specications, but
emission control system performance might be affected.
The malfunction indicator lamp could turn on and your
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-48. If this occurs, return to your
authorized dealer/retailer for diagnosis. If it is determined
that the condition is caused by the type of fuel used,
repairs might not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In most
cases, you should not have to add anything to the fuel.
However, some gasolines contain only the minimum
amount of additive required to meet U.S. Environmental
Protection Agency regulations. To help keep fuel injectors
and intake valves clean, or if your vehicle experiences
problems due to dirty injectors or valves, look for gasolinethat is advertised as TOP TIER Detergent Gasoline. Also,
your dealer/retailer has additives that will help correct and
prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines might be available
in your area. We recommend that you use these
gasolines, if they comply with the specications
described earlier. However, E85 (85% ethanol) and
other fuels containing more than 10% ethanol must
not be used in vehicles that were not designed for
those fuels.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under your
warranty.
Some gasolines that are not reformulated for low
emissions can contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. We recommend against
the use of such gasolines. Fuels containing MMT can
reduce the life of spark plugs and the performance of the
emission control system could be affected. The
malfunction indicator lamp might turn on. If this occurs,
return to your dealer/retailer for service.
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Fuel E85 (85% Ethanol)
The 8th digit of the Vehicle Identication Number (VIN)
shows the code letter or number that identies your
vehicle’s engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification Number
(VIN) on page 5-121.
If your vehicle has the 5.3L V8 engine (VIN Code 0) or
the 5.3L V8 engine (VIN Code 3), you can use either
regular unleaded gasoline or ethanol fuel containing up
to 85% ethanol (E85); also seeFuel on page 5-6.Inall
other engines, use only the unleaded gasoline described
underGasoline Octane on page 5-6.
Only vehicles that have the 5.3L V8 engine
(VIN Code 0) or the 5.3L V8 engine (VIN Code 3) can
use 85% ethanol fuel (E85). We encourage the use
of E85 in vehicles that are designed to use it. The
ethanol in E85 is a “renewable” fuel, meaning it is made
from renewable sources such as corn and other crops.Many service stations will not have an 85% ethanol fuel
(E85) pump available. The U. S. Department of
Energy has an alternative fuels website
(www.eere.energy.gov/afdc/infrastructure/locator.html)
that can help you nd E85 fuel. Those stations that
do have E85 should have a label indicating ethanol
content. Do not use the fuel if the ethanol content
is greater than 85%.
At a minimum, E85 should meet ASTM Specication
D 5798. By denition, this means that fuel labeled E85
will have an ethanol content between 70% and 85%.
Filling the fuel tank with fuel mixtures that do not meet
ASTM specications can affect driveability and could
cause the malfunction indicator lamp to come on.
5-8

Filling the Tank
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Do not use cellular phones. Keep sparks,
ames, and smoking materials away from fuel.
Do not leave the fuel pump unattended when
refueling your vehicle. This is against the law
in some places. Do not re-enter the vehicle
while pumping fuel. Keep children away from
the fuel pump; never let children pump fuel.The tethered fuel cap is located behind a hinged fuel
door on the driver’s side of the vehicle. If the vehicle has
E85 fuel capability, a yellow cap with the words
“E85 / Gasoline” can be seen.
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Filling a Portable Fuel Container
{CAUTION:
Never ll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the fuel vapor. You
can be badly burned and your vehicle
damaged if this occurs. To help avoid injury to
you and others:
Dispense fuel only into approved
containers.
Do not ll a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed, or
on any surface other than the ground.
Bring the ll nozzle in contact with the
inside of the ll opening before operating
the nozzle. Contact should be maintained
until the lling is complete.
Do not smoke while pumping fuel.
Do not use a cellular phone while
pumping fuel.
Checking Things Under the
Hood
{CAUTION:
An electric engine cooling fan can start even
when the engine is not running. To avoid
injury, always keep hands, clothing, and tools
away from any engine cooling fan.
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
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Engine Compartment Overview
If your vehicle has the DURAMAX®Diesel engine, see the DURAMAX®Diesel manual for more information.
When you open the hood on the 5.3L engine (4.3L, 4.8L and 6.0L similar), this is what you will see:
5-14

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter (Gasoline Engines) on page 5-19.
B. Air Filter Restriction Indicator (If Equipped).
SeeEngine Air Cleaner/Filter (Gasoline Engines)
on page 5-19.
C. Coolant Surge Tank and Pressure Cap. SeeCooling
System on page 5-34andCoolant Surge Tank
Pressure Cap on page 5-30.
D. Positive (+) Terminal. SeeJump Starting
on page 5-46.
E. Battery. SeeBattery on page 5-45.
F. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil (Gasoline Engine) on page 5-15.
G. Automatic Transmission Dipstick. See “Checking the
Fluid Level” underAutomatic Transmission Fluid
(6-Speed Transmission) on page 5-22orAutomatic
Transmission Fluid (4-Speed Transmission)
on page 5-25.
H. Remote Negative (−) Terminal (Out of View). See
Jump Starting on page 5-46.
I. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil (Gasoline Engine)
on page 5-15.
J. Engine Cooling Fan. SeeCooling System
on page 5-34.
K. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.L. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-42.
M. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-126.
N. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
Engine Oil (Gasoline Engine)
If your vehicle has a diesel engine, see “Engine Oil” in
the DURAMAX®Diesel manual.
Checking Engine Oil
It is a good idea to check the engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-14for
the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-15

When to Add Engine Oil
If the oil is below the cross-hatched area at the tip of
the dipstick, add at least one quart/liter of the
recommended oil. This section explains what kind of oil
to use. For engine oil crankcase capacity, see
Capacities and Specifications on page 5-130.
Notice:Do not add too much oil. If the engine has
so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, the engine could be damaged.SeeEngine Compartment
Overview on page 5-14for
the location of the engine
oil ll cap.
Be sure to add enough oil to put the level somewhere in
the proper operating range. Push the dipstick all the
way back in when you are through.
5-16

What Kind of Engine Oil to Use
Look for three things:
GM6094M
Your vehicle’s engine requires oil meeting
GM Standard GM6094M. Look for and use only an
oil that meets GM Standard GM6094M.
SAE 5W-30
As shown in the viscosity chart, SAE 5W-30 is best
for your vehicle.These numbers on an oil container show its
viscosity, or thickness. Do not use other viscosity
oils such as SAE 20W-50.
Oils meeting these
requirements should
have the starburst
symbol on the container.
This symbol indicates
that the oil has
been certied by the
American Petroleum
Institute (API).
Look for this information on the oil container, and
use only those oils that are identied as meeting
GM Standard GM6094M and have the starburst
symbol on the front of the oil container.
Notice:Use only engine oil identied as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certied For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both provide easier
cold starting and better protection for the engine at
extremely low temperatures.
5-17