Cadillac CT6 Owner Manual (GMNA-Localizing-U.S./Canada-13566829) -
2020 - CRC - 6/14/19
DRIVING AND OPERATING 259
Recommended Fuel (4.2L
Twin Turbo V8 Engine)
Use premium unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 93—
(R+M)/2. If unavailable, unleaded
gasoline with a posted octane rating
of 91 may be used, but with reduced
performance and fuel economy. If the
octane is less than 91, the engine
could be damaged and the repairs
would not be covered by the vehicle
warranty. If heavy knocking is heard
when using gasoline rated at
93 octane, 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.
. Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control system
and spark plugs.
(Continued)
Caution (Continued)
.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 0259.
Fuel Additives
TOP TIER Detergent Gasoline is highly
recommended for use with your
vehicle. If your country does not have
TOP TIER Detergent Gasoline, add
ACDelco Fuel System Treatment Plus
−Gasoline to the vehicle’s gasoline fuel
tank at every oil change or 15 000 km
(9,000 mi), whichever occurs first. TOP
TIER Detergent Gasoline and ACDelco
Fuel System Treatment Plus−Gasoline
