octane GMC SIERRA 2020 Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
280 Driving and Operating
system does not need service.
Clean the outside of the windshield
behind the rearview mirror.
LKA assistance and/or LDW alerts
may occur due to tar marks,
shadows, cracks in the road,
temporary or construction lane
markings, or other road
imperfections. This is normal system
operation; the vehicle does not need
service. Turn LKA off if these
conditions continue.Fuel
Top Tier Fuel
GM recommends the use of TOP
TIER Detergent Gasoline to keep
the engine clean, reduce engine
deposits, and maintain optimal
vehicle performance. Look for the
TOP TIER Logo or see
www.toptiergas.com for a list of TOP
TIER Detergent Gasoline marketers
and applicable countries.
Recommended Fuel
(Except 6.2L V8 Engine)
For diesel engine vehicles, see
“Fuel for Diesel Engines”in the
Duramax diesel supplement.
If the vehicle has a yellow fuel cap
or a yellow sticker on the fuel door,
E85 or FlexFuel can be used. If the
vehicle does not have a yellow fuel
cap or yellow sticker, do not use
gasoline with ethanol levels greater
than 15% by volume. See E85 or
FlexFuel 0282.
Use regular unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 87 —
(R+M)/2 —or higher. Do not use
gasoline with a posted octane rating
of less than 87, as this may cause
engine knock and will lower fuel
economy.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 281
Recommended Fuel (6.2L
V8 Engine)
Premium unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 93—
(R+M)/2 —is highly recommended
for best performance and fuel
economy. Unleaded gasoline with
an octane rated as low as 87 can be
used. Using unleaded gasoline
rated below 93 octane, however, will
lead to reduced acceleration and
fuel economy. If knocking occurs,
use a gasoline rated at 93 octane
as soon as possible, otherwise, the
engine could be damaged. If heavy
knocking is heard when using
gasoline with a 93 octane rating, the
engine needs service. Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so
may damage the vehicle and void
its warranty:
. For vehicles that are not
FlexFuel, fuel labeled
greater than 15% ethanol by
volume, such as mid-level
ethanol blends (16–50%
ethanol), E85, or FlexFuel.
. Fuel with any amount of
methanol, methylal,
ferrocene, and aniline.
These fuels can corrode
metal fuel system parts or
damage plastic and rubber
parts.
(Continued)
Caution (Continued)
.Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control
system and spark plugs.
. Fuel with a posted octane
rating of less than the
recommended fuel. Using
this fuel will lower fuel
economy and performance,
and may decrease the life of
the emissions catalyst.
Fuels in Foreign
Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock
index (AKI). For fuel not to use in a
foreign country, see Prohibited
Fuels 0281.