2004 GMC SIERRA DENALI engine

If you want to get service information, seeService
Publications Ordering Information on page 7-11.
Owner Checks and Services on page 6-9tells you what
should be checked, when to check it and what you
can easily do to help keep your vehicle in good
condition.
The proper replacement parts, ¯uids and lubricants to
use are listed in
Recommended Fluids and Lubricants
on page 6-13andNormal Maintenance Replacement
Parts on page 6-15. When your vehicle is serviced,
make sure these are used. All parts should be replaced
and all necessary repairs done before you or anyone
else drives the vehicle. We recommend the use of
genuine GM parts.
Scheduled Maintenance
When the CHANGE ENGINE OIL message comes on, it
means that service is required for your vehicle. Have
your vehicle serviced as soon as possible within the next
600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the engine oil
life system may not indicate that vehicle service is
necessary for over a year. However, your engine oil and
®lter must be changed at least once a year and at
this time the system must be reset.Your GM Goodwrench dealer has GM-trained service
technicians who will perform this work using genuine GM
parts and reset the system.
If the engine oil life system is ever reset accidentally,
you must service your vehicle within 3,000 miles
(5 000 km) since your last service. Remember to reset
the oil life system whenever the oil is changed. See
Engine Oil on page 5-11for information on the Engine
Oil Life System and resetting the system.
When the CHANGE ENGINE OIL message appears,
certain services, checks and inspections are required.
Required services are described in the following for
ªMaintenanceIº and ªMaintenanceII.º Generally,
it is recommended that your ®rst service be
MaintenanceI, your second service be MaintenanceII
and that you alternate MaintenanceIand MaintenanceII
thereafter. However, in some cases, MaintenanceII
may be required more often.
MaintenanceIÐ Use MaintenanceIif the CHANGE
ENGINE OIL message comes on within ten months
since vehicle was purchased or MaintenanceII
was performed.
MaintenanceIIÐ Use MaintenanceIIif the previous
service performed was MaintenanceI. Always use
MaintenanceIIwhenever the message comes on ten
months or more since the last service or if the message
has not come on at all for one year.
6-4

Scheduled Maintenance
Service MaintenanceIMaintenanceII
Change engine oil and ®lter. Reset oil life system. See
Engine Oil on
page 5-11.An Emission Control Service.··
Lubricate chassis components.
See footnote #.··
Visually check for any leaks or damage.
See footnote (j).··
Inspect engine air cleaner ®lter or change indicator (if equipped). If necessary,
replace ®lter. See
Engine Air Cleaner/Filter on page 5-16.An Emission Control
Service. See footnote ².··
Rotate tires and check in¯ation pressures and wear. See
Tires on page 5-59.··
Inspect brake system.
See footnote (a).··
Check engine coolant and windshield washer ¯uid levels and add ¯uid as
needed.··
Perform any needed additional services. See ªAdditional Required Servicesº in
this section.··
Inspect suspension and steering components.
See footnote (b).·
Inspect engine cooling system.
See footnote (c).·
Inspect wiper blades.
See footnote (d).·
Inspect restraint system components.
See footnote (e).·
Lubricate body components.
See footnote (f).·
Check transmission ¯uid level and add ¯uid as needed.·
6-5

Additional Required Services
The following services should be performed at the ®rst maintenance service (IorII) after the indicated miles
(kilometers) shown for each item.
Additional Required Services
Service25,000
(41 500)50,000
(83 000)75,000
(125 000)100,000
(166 000)125,000
(207 500)150,000
(240 000)
Inspect fuel system for damage
or leaks.······
Inspect exhaust system for loose or
damaged components.······
Vehicles without a ®lter restriction
indicator: Replace engine air cleaner
®lter. See
Engine Air Cleaner/Filter on
page 5-16.An Emission Control
Service.······
Change automatic transmission ¯uid
and ®lter (severe service).
See footnote (h).···
Change automatic transmission ¯uid
and ®lter (normal service).·
Inspect evaporative control system.
An Emission Control Service. See
footnotes ² and (g).···
6-6

Additional Required Services (cont'd)
Service25,000
(41 500)50,000
(83 000)75,000
(125 000)100,000
(166 000)125,000
(207 500)150,000
(240 000)
Replace spark plugs and inspect spark
plug wires.
An Emission Control
Service.·
Engine cooling system service
(or every 5 years, whichever occurs
®rst).
An Emission Control Service.
See footnote (i).·
Inspect engine accessory drive belt.
An Emission Control Service.·
6-7

(g)Add ¯uid as needed. A ¯uid loss could indicate a
problem; repair as needed. Check vent hose at transfer
case for kinks and proper installation.
(h)Change automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þIn heavy city traffic where the outside temperature
regularly reaches 90ÉF (32ÉC) or higher.
þIn hilly or mountainous terrain.
þWhen doing frequent trailer towing.
þUses such as found in taxi, police or delivery
service.
(i)Drain, ¯ush and re®ll cooling system. See Engine
Coolant on page 5-21for what to use. Inspect hoses.
Clean radiator, condenser, pressure cap and ®ller neck.
Pressure test the cooling system and pressure cap.
(j)
A ¯uid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the ¯uid level checked. Add ¯uid if needed.
(k)Inspect system. Check all fuel and vapor lines and
hoses for proper hook-up, routing and condition.
Check that the purge valve works properly (if equipped).
Replace as needed.
Owner Checks and Services
These owner checks and services should be performed
at the intervals speci®ed to help ensure the safety,
dependability and emission control performance of your
vehicle. Your GM Goodwrench dealer can assist you
with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any ¯uids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
in
Recommended Fluids and Lubricants on page 6-13.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel ®ll.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-11for further
details.
Notice:It is important to check your oil regularly
and keep it at the proper level. Failure to keep your
engine oil at the proper level can cause damage
to your engine not covered by your warranty.
6-9

Engine Coolant Level Check
Check the engine coolant level and add
DEX-COOLžcoolant mixture if necessary. SeeEngine
Coolant on page 5-21for further details.
Windshield Washer Fluid Level Check
Check the windshield washer ¯uid level in the windshield
washer tank and add the proper ¯uid if necessary.
At Least Once a Month
Tire In¯ation Check
Visually inspect your tires and make sure tires are
in¯ated to the correct pressures. Do not forget to check
your spare tire. See
Tires on page 5-59for further
details. Check to make sure the spare tire is stored
securely. Push, pull and then try to rotate or turn
the spare tire. If it moves, tighten it. See
Changing a
Flat Tire on page 5-76.
At Least Once a Year
Starter Switch Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular
brake. See
Parking Brake on page 2-25if
necessary.
Do not use the accelerator pedal, and be ready to
turn off the engine immediately if it starts.
3. Try to start the engine in each gear. The starter
should work only in PARK (P) or NEUTRAL (N).
If the starter works in any other position, contact
your GM Goodwrench dealer for service.
6-10

Automatic Transmission Shift Lock
Control System Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle. It should be parked on a level
surface.
2. Firmly apply the parking brake. See
Parking Brake
on page 2-25if necessary.
Be ready to apply the regular brake immediately if
the vehicle begins to move.3. With the engine off, turn the key to the RUN
position, but do not start the engine. Without
applying the regular brake, try to move the shift
lever out of PARK (P) with normal effort. If the shift
lever moves out of PARK (P), contact your GM
Goodwrench dealer for service.
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.
·The key should turn to LOCK only when the
shift lever is in PARK (P).
·The key should come out only in LOCK.
Contact your GM Goodwrench dealer if service is
required.
6-11

Parking Brake and Automatic
Transmission Park (P) Mechanism Check
{CAUTION:
When you are doing this check, your vehicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room in front of your vehicle in
case it begins to roll. Be ready to apply the
regular brake at once should the vehicle begin
to move.Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake, set the
parking brake.
·To check the parking brake's holding ability: With
the engine running and transmission in
NEUTRAL (N), slowly remove foot pressure from
the regular brake pedal. Do this until the vehicle is
held by the parking brake only.
·To check the PARK (P) mechanism's holding ability:
With the engine running, shift to PARK (P). Then
release the parking brake followed by the regular
brake.
Contact your GM Goodwrench dealer if service is
required.
Underbody Flushing Service
At least every spring, use plain water to ¯ush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
6-12