Recommended Fuel; Use Of Seasonal Fuels; Prohibited Fuels - Cadillac ATS 2014 Owner's Manual

9-64 Driving and Operating

Recommended Fuel

If the vehicle has a 2.5L L4 engine
or a 3.6L V6 engine, use regular
unleaded gasoline with a posted
octane rating of 87 or higher. If the
octane rating is less than 87, an
audible knocking noise, commonly
referred to as spark knock, might be
heard when driving. If this occurs,
use a gasoline rated at 87 octane or
higher as soon as possible. If heavy
knocking is heard when using
gasoline rated at 87 octane or
higher, the engine needs service.
If the vehicle has the 2.0L
L4 engine, use premium unleaded
gasoline with a posted octane rating
of 91 or higher. You can also use
regular unleaded gasoline rated at
87 octane or higher, but the
vehicle's acceleration could be
slightly reduced, and a slight audible
knocking noise, commonly referred
to as spark knock, might be heard.
If the octane is less than 87, a
heavy knocking noise might be
heard when driving. If this occurs,
use a gasoline rated at 87 octane or
higher as soon as possible.
Otherwise, you could damage the
engine. If heavy knocking is heard
when using gasoline rated at
87 octane or higher, the engine
needs service.

Use of Seasonal Fuels

Use summer and winter fuels in the
appropriate season. Driving or
starting could be affected if the
incorrect fuel is used. Drive the
vehicle with the engine running until
the fuel is a half tank or less, then
refuel with the current seasonal fuel.

Prohibited Fuels

Gasolines containing oxygenates,
such as ethers and ethanol, as well
as reformulated gasolines are
available in some cities. If these
gasolines comply with the
previously described specification,
then they are acceptable to use.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must be used only in
flex fuel vehicles.
Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Some gasolines that are not
reformulated for low emissions can
contain an octane-enhancing
additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines with MMT as they can
reduce spark plug life and affect
emission control system
performance. The malfunction
indicator lamp may turn on. If this
occurs, see your dealer for service.