2015 GMC SIERRA DENALI coolant level

Black plate (4,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
iv Introduction
Danger, Warnings, and
Cautions Warning messages found on vehicle
labels and in this manual describe
hazards and what to do to avoid or
reduce them.
{ DangerDanger indicates a hazard with a
high level of risk which will result
in serious injury or death.
{ Warning
Warning indicates a hazard that
could result in injury or death.
{ Caution
Caution indicates a hazard that
could result in property or vehicle
damage. A circle with a slash through it is a
safety symbol which means “ Do
Not, ” “ Do not do this, ” or “ Do not let
this happen. ”
Symbols The vehicle has components and
labels that use symbols instead of
text. Symbols are shown along with
the text describing the operation or
information relating to a specific
component, control, message,
gauge, or indicator.
M : This symbol is shown when
you need to see your owner manual
for additional instructions or
information.
* : This symbol is shown when
you need to see a service manual
for additional instructions or
information. Vehicle Symbol Chart
Here are some additional symbols
that may be found on the vehicle
and what they mean. For more
information on the symbol, refer to
the Index.
0 : Adjustable Pedals
9 : Airbag Readiness Light
! : Antilock Brake System (ABS)
g : Audio Steering Wheel Controls
or OnStar ®
(if equipped)
$ : Brake System Warning Light
" : Charging System
I : Cruise Control
B : Engine Coolant Temperature
O : Exterior Lamps
# : Fog Lamps
. : Fuel Gauge
+ : Fuses
3 : Headlamp High/Low-Beam
Changer
( : Heated Steering Wheel

Black plate (13,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-13
English, Standard Theme Shown
The engine oil pressure gauge
shows the engine oil pressure
in kPa (kilopascals) or psi (pounds
per square inch) when the engine is
running.
Oil pressure can vary with engine
speed, outside temperature and oil
viscosity.
A reading outside the normal
operating range can be caused by a
dangerously low oil level or some
other problem causing low oil
pressure. Check the vehicle's oil as
soon as possible. See “ OIL PRESSURE LOW STOP
ENGINE ” under Engine Oil
Messages on page 5-34 and Engine
Oil on page 10-8 .
{ CautionLack of proper engine oil
maintenance can damage the
engine. Driving with the engine
oil low can also damage the
engine. The repairs would not be
covered by the vehicle warranty.
Check the oil level as soon as
possible. Add oil if required, but if
the oil level is within the operating
range and the oil pressure is still
low, have the vehicle serviced.
Always follow the maintenance
schedule for changing engine oil.
If the vehicle has a diesel engine,
see the Duramax diesel
supplement. Engine Coolant
Temperature Gauge
Metric, Standard Theme Shown

Black plate (14,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-14 Instruments and Controls
English, Standard Theme Shown
This gauge measures the
temperature of the vehicle's engine
coolant.
While driving under normal
operating conditions, if the needle
moves into the red warning area,
the engine is too hot. Pull off the
road, stop the vehicle, and turn off
the engine as soon as possible. Transmission
Temperature Gauge
Metric, Standard Theme Shown English, Standard Theme Shown
This gauge appears when the
vehicle is in Tow/Haul Mode and
shows the transmission fluid
temperature. If the gauge is reading
in the red area and/or a message
appears in the Driver Information
Center (DIC), the vehicle must be
stopped and the cause checked.
One possible cause is a low fluid
level in the transmission.
See Transmission Messages on
page 5-39 .

Black plate (34,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-34 Instruments and Controls
Engine Oil Messages CHANGE ENGINE OIL SOON This message displays when the
engine oil needs to be changed.
When you change the engine oil, be
sure to reset the CHANGE ENGINE
OIL SOON message. See Engine
Oil Life System on page 10-11 for
information on how to reset the
message. See Engine Oil on
page 10-8 and Maintenance
Schedule on page 11-3 .
ENGINE OIL LOW ADD OIL On some vehicles, this message
displays when the engine oil level
may be too low. Check the oil level
before filling to the recommended
level. If the oil is not low and this
message remains on, take the
vehicle to your dealer for service.
See Engine Oil on page 10-8 . ENGINE OIL HOT IDLE
ENGINE This message displays when the
engine oil becomes hotter than the
normal operating temperature. Stop
and allow the vehicle to idle until it
cools down. See Engine Coolant
Temperature Gauge on page 5-13 .
OIL PRESSURE LOW STOP
ENGINE This message displays if low oil
pressure levels occur. Stop the
vehicle as soon as safely possible
and do not operate it until the cause
of the low oil pressure has been
corrected. Check the oil as soon as
possible and have the vehicle
serviced by your dealer. See Engine
Oil on page 10-8 .
Engine Power Messages ENGINE POWER IS REDUCED
This message displays and a chime
may sound when the cooling system
temperature gets too hot and the engine further enters the engine
coolant protection mode. See
Engine Overheating on page 10-21
for more information.
This message also displays when
the vehicle's engine power is
reduced. Reduced engine power
can affect the vehicle's ability to
accelerate. If this message is on,
but there is no reduction in
performance, proceed to your
destination. The performance may
be reduced the next time the vehicle
is driven. The vehicle may be driven
at a reduced speed while this
message is on, but acceleration and
speed may be reduced. Anytime
this message stays on, the vehicle
should be taken to your dealer for
service as soon as possible.

Black plate (70,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-70 Driving and Operating If the trailer turn signal bulbs burn
out, the arrows on the instrument
cluster will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the
transmission is not shifted down, the
brakes might get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The Tow/Haul Mode may be used if
the transmission shifts too often.
See Tow/Haul Mode on page 9-39 .
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, see Engine Overheating on
page 10-21 .
Parking on Hills
{ WarningParking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet. Turn
the wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks
under the trailer wheels.
3. When the wheel chocks are in
place, release the regular brakes
until the chocks absorb the load.
4. Reapply the brake pedal. Then
apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill 1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is
clear of the chocks.

Black plate (8,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-8 Vehicle Care 1. Positive (+) Terminal. See Jump
Starting on page 10-87 .
2. Battery on page 10-29 .
3. Coolant Surge Tank and
Pressure Cap. See Cooling
System on page 10-17 .
4. Engine Air Cleaner/Filter on
page 10-15 .
5. Automatic Transmission
Dipstick. See “ How to Check the
Automatic Transmission Fluid ”
under Automatic Transmission
Fluid (6 Speed Transmission) on
page 10-12 or Automatic
Transmission Fluid (8 Speed
Transmission) on page 10-15 .
6. Engine Oil Dipstick. See
“ Checking Engine Oil ” under
Engine Oil on page 10-8 .
7. Engine Oil Fill Cap. See “ When
to Add Engine Oil ” under Engine
Oil on page 10-8 .
8. Engine Cooling Fan (Out of
View). See Cooling System on
page 10-17 . 9. Remote Negative ( – ) Location.
See Jump Starting on
page 10-87 .
10. Power Steering Fluid
Reservoir. See Power Steering
Fluid (1500 Series) on
page 10-24 or Power Steering
Fluid (2500/3500 Series) on
page 10-24 .
11. Windshield Washer Fluid
Reservoir. See “ Adding Washer
Fluid ” under Washer Fluid on
page 10-25 .
12. Brake Fluid Reservoir. See
Brake Fluid on page 10-27 .
13. Auxiliary Battery (If Equipped).
See Battery on page 10-29 .
14. Engine Compartment Fuse
Block on page 10-41 .
If the vehicle has a diesel engine
and/or an Allison Transmission, see
the Duramax diesel supplement. Engine Oil For diesel engine vehicles, see
“ Engine Oil ” in the Duramax diesel
supplement.
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment: .
Always use engine oil approved
to the proper specification and of
the proper viscosity grade. See
“ Selecting the Right Engine Oil ”
in this section. .
Check the engine oil level
regularly and maintain the
proper oil level. See “ Checking
Engine Oil ” and “ When to Add
Engine Oil ” in this section. .
Change the engine oil at the
appropriate time. See Engine Oil
Life System on page 10-11 . .
Always dispose of engine oil
properly. See “ What to Do with
Used Oil ” in this section.

Black plate (19,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-19Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture: .
Gives freezing protection down
to − 37°C ( − 34°F), outside
temperature. .
Gives boiling protection up to
129°C (265°F), engine
temperature. .
Protects against rust and
corrosion. .
Will not damage aluminum parts. .
Helps keep the proper engine
temperature.
{ Caution
If improper coolant mixture,
inhibitors, or additives are used in
the vehicle cooling system, the
engine could overheat and be
damaged. Too much water in the
(Continued) Caution (Continued) mixture can freeze and crack
engine cooling parts. The repairs
would not be covered by the
vehicle warranty. Use only the
proper mixture of engine coolant
for the cooling system. See
Recommended Fluids and
Lubricants on page 11-12 .
Never dispose of engine coolant by
putting it in the trash, or by pouring
it on the ground, or into sewers,
streams, or bodies of water. Have
the coolant changed by an
authorized service center, familiar
with legal requirements regarding
used coolant disposal. This will help
protect the environment and your
health. Checking Coolant The coolant surge tank is in the
engine compartment on the
passenger side of the vehicle. See
Engine Compartment Overview on
page 10-5 .
The vehicle must be on a level
surface when checking the coolant
level.
Check to see if coolant is visible in
the coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, do not do anything else until
it cools down. If coolant is visible
but the coolant level is not at or
above the FULL COLD mark, add a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant at the
coolant surge tank, but be sure the
cooling system is cool before this
is done.

Black plate (20,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-20 Vehicle Care
5.3L V8 Engine Shown, 6.2L
V8 Engine Similar
6.0L V8 Engine The coolant level should be at or
above the FULL COLD mark. If it is
not, there may be a leak in the
cooling system.
How to Add Coolant to the
Coolant Surge Tank If the vehicle has a diesel engine,
see “ Cooling System ” in the
Duramax diesel supplement for the
proper coolant fill procedure.
{ WarningYou 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. { CautionThis vehicle has a specific
coolant fill procedure. Failure to
follow this procedure could cause
the engine to overheat and be
severely damaged.
{ WarningSteam and scalding liquids from a
hot cooling system can blow out
and burn you badly. Never turn
the cap when the cooling system,
including the surge tank pressure
cap, is hot. Wait for the cooling
system and surge tank pressure
cap to cool.
If no coolant is visible in the surge
tank, add coolant.