Adding Equipment To The Outside Of Your Vehicle; Fuel; Gasoline Octane; Gasoline Specifications - GMC 2008 Acadia Owner's Manual

Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your 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 your vehicle.

Fuel

Use of the recommended fuel is an important part of the
proper maintenance of your vehicle. To help keep the
engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline.
5-6

Gasoline Octane

Use regular unleaded gasoline with a posted octane
rating of 87 or higher. For best performance or
trailer towing, you could choose to use middle grade 89
octane unleaded gasoline. 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.
Gasoline Specifications
At a minimum, gasoline should meet ASTM specification
D 4814 in the United States or CAN/CGSB-3.5 or
3.511 in Canada. Some gasolines contain an
octane-enhancing additive called methylcyclopentadienyl
manganese tricarbonyl (MMT). We recommend
against the use of gasolines containing MMT. See
Additives on page 5-7 for additional information.