Fuel; Gasoline Octane; Gasoline Specifications - GMC 2007 Savana Van Owner's Manual

Fuel

If your vehicle has a diesel engine, see "Diesel
Fuel Requirements and Fuel System" in the
®
DURAMAX Diesel Supplement.
For vehicles with gasoline engines, please
read this.
Gasoline
Use of the recommended fuel is an important part
of the proper maintenance of your vehicle. To
help keep your engine clean and maintain optimum
vehicle performance, GM recommends the use
of gasoline advertised as TOP TIER Detergent
Gasoline.
The 8th digit of your Vehicle Identification
Number (VIN) shows the code letter or number
that identifies your engine. You will find the VIN at
the top left of the instrument panel. See Vehicle
Identification Number (VIN) on page 386.
If your vehicle has the 5.3L V8 engine
(VIN Code Z), you may use either regular
unleaded gasoline or ethanol fuel containing
up to 85% ethanol (E85); also see Fuel E85
(85% Ethanol) on page 290. In all other gasoline
engines, use only regular unleaded gasoline.
288

Gasoline Octane

Use regular unleaded gasoline with a posted
octane rating of 87 or higher. If the octane rating
is less than 87, you may 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, your engine
needs service.
Gasoline Specifications
At a minimum, gasoline should meet ASTM
specification D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. See Additives on
page 289 for additional information.