Adding Equipment To The Outside Of The Vehicle; Fuel; Gasoline Octane - Chevrolet 2009 Cobalt Owner's Manual

Keep a record with all parts receipts and list the
mileage and the date of any service work performed.
See Maintenance Record on page 6-16.
Adding Equipment to the Outside of
the Vehicle
Things added to the outside of the vehicle can affect the
airflow around it. This can cause wind noise and can
affect fuel economy and windshield washer performance.
Check with your dealer/retailer before adding equipment
to the outside of the vehicle.

Fuel

Use of the recommended fuel is an important part of the
proper maintenance of this vehicle. To help keep the
engine clean and maintain optimum vehicle performance,
we recommend the use of gasoline advertised as TOP
TIER Detergent Gasoline.
The 8th digit of the Vehicle Identification Number (VIN)
shows the code letter or number that identifies the
vehicle's engine. The VIN is at the top left of the
instrument panel. See Vehicle Identification Number
(VIN) on page 5-117.

Gasoline Octane

If the vehicle has the 2.2L L4 engine (VIN Code H),
use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you might notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking, the
engine needs service.
If the vehicle has the 2.0L L4 engine (VIN Code X),
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
you might notice a slight audible knocking noise,
commonly referred to as spark knock. If the octane is
less than 87, you might notice a heavy knocking
noise when you drive. If this occurs, use a gasoline
rated at 87 octane or higher as soon as possible.
Otherwise, you could damage the engine. If you are
using gasoline rated at 87 octane or higher and you hear
heavy knocking, the engine needs service.
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