2015 GMC SIERRA DENALI fuel cap

Black plate (66,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-66 Driving and Operating
Filling the Tank If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.
{ WarningFuel vapors and fuel fires burn
violently and can cause injury or
death. .
To help avoid injuries to you
and others, read and follow
all the instructions on the fuel
pump island. .
Turn off the engine when
refueling. .
Keep sparks, flames, and
smoking materials away
from fuel. .
Do not leave the fuel pump
unattended. .
Do not reenter the vehicle
while pumping fuel.
(Continued) Warning (Continued) .
Keep children away from the
fuel pump and never let
children pump fuel. .
Fuel can spray out if the fuel
cap is opened too quickly.
This spray can happen if the
tank is nearly full, and is
more likely in hot weather.
Open the fuel cap slowly and
wait for any hiss noise to stop
then unscrew the cap all
the way. The fuel cap is behind a hinged fuel
door on the driver side of the
vehicle. Vehicles that have a
FlexFuel badge and a yellow fuel
cap can use either unleaded
gasoline or ethanol fuel containing
up to 85% ethanol (E85). See E85
or FlexFuel on page 9-65 .
To remove the fuel cap, turn it
slowly counterclockwise.
If the vehicle is a dual fuel tank
chassis cab model, and it runs out
of fuel, refuel the front fuel tank first
to ensure a quick restart.

Black plate (67,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-67Be careful not to spill fuel. Do not
top off or overfill the tank and wait a
few seconds after you have finished
pumping before removing the
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care on page 10-96 .
When replacing the fuel cap, turn it
clockwise until it clicks. It will require
more effort to turn the fuel cap on
the last turn as you tighten it. Make
sure the cap is fully installed. The
diagnostic system can determine if
the fuel cap has been left off or
improperly installed. This would
allow fuel to evaporate into the
atmosphere. See Malfunction
Indicator Lamp on page 5-18 .
The TIGHTEN GAS CAP message
displays on the Driver Information
Center (DIC) if the fuel cap is not
properly installed. See Fuel System
Messages on page 5-35 for more
information. { WarningIf a fire starts while you are
refueling, do not remove the
nozzle. Shut off the flow of fuel by
shutting off the pump or by
notifying the station attendant.
Leave the area immediately.
{ CautionIf a new fuel cap is needed, be
sure to get the right type of cap
from your dealer. The wrong type
of fuel cap may not fit properly,
may cause the malfunction
indicator lamp to light, and could
damage the fuel tank and
emissions system. See
Malfunction Indicator Lamp on
page 5-18 . Filling a Portable Fuel
Container
{ WarningFilling a portable fuel container
while it is in the vehicle can cause
fuel vapors that can ignite either
by static electricity or other
means. You or others could be
badly burned and the vehicle
could be damaged. Always: .
Use approved fuel
containers. .
Remove the container from
the vehicle, trunk, or pickup
bed before filling. .
Place the container on the
ground. .
Place the nozzle inside the fill
opening of the container
before dispensing fuel, and
(Continued)

Black plate (71,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-717. Stop and have someone pick up
and store the chocks.
Maintenance when Trailer
Towing The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11-3 . Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
If the vehicle is bi-fuel, see the
bi-fuel supplement. Do not tow a trailer during break-in.
See New Vehicle Break-In on
page 9-23 for more information.
{ WarningThe driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too
heavy, the brakes may not work
well or even at all. The driver and
passengers could be seriously
injured. The vehicle may also be
damaged; the resulting repairs
would not be covered by the
vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle. { CautionPulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
See Vehicle Load Limits on
page 9-15 for more information
about the vehicle's maximum load
capacity.
To identify the trailering capacity of
the vehicle, read the information in
“ Weight of the Trailer ” later in this
section.

Black plate (89,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-89The plow the vehicle can carry
depends on many things, such as: .
The options the vehicle came
with, and the weight of those
options. .
The weight and number of
passengers intended to be
carried. .
The weight of items added to the
vehicle, like a tool box or
truck cap. .
The total weight of any
additional cargo intended to be
carried.
Say, for example, you have a 318 kg
(700 lb) snow plow. The total weight
of all occupants and cargo inside
the cab should not exceed 135 kg
(300 lb). This means that you may
only be able to carry one passenger.
But, even this may be too much if
there is other equipment already
adding to the weight of the vehicle. Here are some guidelines for safely
carrying a snow plow on the vehicle: .
Make sure the weight on the
front and rear axles does not
exceed the axle rating for each. .
For the front axle, if more cargo
or passengers must be carried,
appropriate counter ballast must
be installed rear of the rear axle.
Counter ballast must be properly
secured so it will not move
during driving. .
Follow the snow plow
manufacturer's
recommendations regarding rear
ballast. Rear ballast may be
required to ensure a proper front
and rear weight distribution ratio,
even though the actual weight at
the front axle may be less than
the front axle rating. .
The snow plow manufacturer or
installer can assist you in
determining the amount of rear
ballast required, to help make
sure the snow plow/vehicle
combination does not exceed
the GVW rating, the front and
rear axle ratings, and the front
and rear weight distribution ratio. .
The total vehicle must not
exceed the GVW rating.
Front axle reserve capacity is the
difference between the Gross Axle
Weight Rating (GAWR) and the front
axle weight of the vehicle with full
fuel and passengers. Basically, it is
the amount of weight that can be
added to the front axle before
reaching the front GAWR.

Black plate (91,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-91This has the effect of reducing the
load on the front. However, the front
GAWR, rear GAWR, and Gross
Vehicle Weight Rating (GVWR) must
never be exceeded.
{ WarningOn some vehicles that have
certain front mounted equipment,
such as a snow plow, it may be
possible to load the front axle to
the front gross axle weight rating
(GAWR) but not have enough
weight on the rear axle to have
proper braking performance. If the
brakes cannot work properly, you
could have a crash. To help the
brakes work properly when a
snow plow is installed, always
follow the snow plow
manufacturer or installer's
recommendation for rear ballast
to ensure a proper front and rear
weight distribution ratio, even
though the actual front weight
(Continued) Warning (Continued) may be less than the front
GAWR, and the total vehicle
weight is less than the gross
vehicle weight rating (GVWR).
Maintaining a proper front and
rear weight distribution ratio is
necessary to provide proper
braking performance.
Total vehicle reserve capacity is the
difference between the GVWR and
the weight of the truck with full fuel
and passengers. It is the amount of
weight that can be added to the
vehicle before reaching the GVWR.
Keep in mind that reserve capacity
numbers are intended as a guide
when selecting the amount of
equipment or cargo the truck can
carry. If unsure of the vehicle's front,
rear, or total weight, go to a weigh
station and weigh the vehicle. Your
dealer can also help with this. The total vehicle reserve capacity
for the vehicle can be found in the
lower right corner of the
Certification/Tire label as shown
previously.
See your dealer for additional
advice and information about using
a snow plow on the vehicle. Also,
see Vehicle Load Limits on
page 9-15 .
Emergency Roof Lamp
Provisions Vehicles with the RPO VYU snow
plow prep package also have an
emergency roof lamp provision
package, RPO TRW. Wiring for the
emergency roof lamp is provided
above the overhead console. See
Auxiliary Roof-Mounted Lamp on
page 6-5 for switch location.

Black plate (9,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-9Checking Engine Oil It is a good idea to check the engine
oil level at each fuel fill. In order to
get an accurate reading, the vehicle
must be on level ground. The
engine oil dipstick handle is a loop.
See Engine Compartment Overview
on page 10-5 for the location of the
engine oil dipstick.
If a low oil message displays on the
DIC, it is important to park on level
ground to accurately measure the
oil level on the dipstick. Idling the
vehicle on steep grades for a long
time can influence the level sensing
accuracy.
Obtaining an accurate oil level
reading is essential:
1. If the engine has been running
recently, turn off the engine and
allow several minutes for the oil
to drain back into the oil pan.
Checking the oil level too soon
after engine shutoff will not
provide an accurate oil level
reading. { WarningThe engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
2. Pull out the dipstick and wipe it
with a clean paper towel or cloth,
then push it back in all the way.
Remove it again, keeping the tip
down, and check the level.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick, add
1 L (1 qt) of the recommended oil
and then recheck the level. See
“ Selecting the Right Engine Oil ” in
this section for an explanation of what kind of oil to use. For engine
oil crankcase capacity, see
Capacities and Specifications on
page 12-2 .
{ CautionDo not add too much oil. Oil
levels above or below the
acceptable operating range
shown on the dipstick are harmful
to the engine. If you find that you
have an oil level above the
operating range, i.e., 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. You should drain
out the excess oil or limit driving
of the vehicle and seek a service
professional to remove the
excess amount of oil.
See Engine Compartment Overview
on page 10-5 for the location of the
engine oil fill cap.

Black plate (57,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-57maximum capacity of fuel, oil,
and coolant, but without
passengers and cargo.
DOT Markings :
A code molded
into the sidewall of a tire
signifying that the tire is in
compliance with the U.S.
Department of Transportation
(DOT) Motor Vehicle Safety
Standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR :
Gross Vehicle Weight
Rating. See Vehicle Load Limits
on page 9-15 .
GAWR FRT :
Gross Axle Weight
Rating for the front axle. See
Vehicle Load Limits on
page 9-15 . GAWR RR :
Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits on
page 9-15 .
Intended Outboard Sidewall :
The side of an asymmetrical tire
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa) :
The metric
unit for air pressure.
Light Truck (LT-Metric) Tire :
A
tire used on light duty trucks and
some multipurpose passenger
vehicles.
Load Index :
An assigned
number ranging from 1 to 279
that corresponds to the load
carrying capacity of a tire.
Maximum Inflation Pressure :
The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is
molded onto the sidewall. Maximum Load Rating :
The
load rating for a tire at the
maximum permissible inflation
pressure for that tire.
Maximum Loaded Vehicle
Weight :
The sum of curb
weight, accessory weight,
vehicle capacity weight, and
production options weight.
Normal Occupant Weight :
The
number of occupants a vehicle
is designed to seat multiplied by
68 kg (150 lb). See Vehicle Load
Limits on page 9-15 .
Occupant Distribution :
Designated seating positions.
Outward Facing Sidewall :
The
side of an asymmetrical tire that
has a particular side that faces
outward when mounted on a
vehicle. The side of the tire that
contains a whitewall, bears
white lettering, or bears
manufacturer, brand, and/or

Black plate (59,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-59Vehicle Placard :
A label
permanently attached to a
vehicle showing the vehicle
capacity weight and the original
equipment tire size and
recommended inflation pressure.
See “ Tire and Loading
Information Label ” under Vehicle
Load Limits on page 9-15 .
Tire Pressure Tires need the correct amount of
air pressure to operate
effectively. { Caution
Neither tire underinflation nor
overinflation is good.
Underinflated tires, or tires
that do not have enough air,
can result in: .
Tire overloading and
overheating which could
lead to a blowout. .
Premature or
irregular wear. .
Poor handling. .
Reduced fuel economy.
Overinflated tires, or tires that
have too much air, can
result in: .
Unusual wear. .
Poor handling. .
Rough ride. .
Needless damage from
road hazards. The Tire and Loading
Information label on the vehicle
indicates the original equipment
tires and the correct cold tire
inflation pressures. The
recommended pressure is the
minimum air pressure needed to
support the vehicle's maximum
load carrying capacity.
For additional information
regarding how much weight the
vehicle can carry, and an
example of the Tire and Loading
Information label, see Vehicle
Load Limits on page 9-15 . How
the vehicle is loaded affects
vehicle handling and ride
comfort. Never load the vehicle
with more weight than it was
designed to carry.
When to Check
Check the tires once a month
or more.