Fuel
For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax diesel supplement.
GM recommends the use of TOP TIER Detergent Gasoline to keep the engine cleaner and reduce engine deposits. See www.toptiergas.com for a list of TOP TIER Detergent Gasoline marketers and applicable countries.
If the vehicle has a yellow sticker on the fuel door, E85 or FlexFuel can be used. See E85 or FlexFuel
0 293.
Except the 6.2L engine, use regular unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 87 or higher. Do not use gasoline with a posted octane rating of less than 87, as this may cause engine knock and will lower fuel economy.
For the 6.2L engine, premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 is highly recommended for best performance and fuel economy. Unleaded gasoline with an octane rated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy.
If knocking occurs, use a gasoline rated at 93 octane as soon as possible, otherwise, the engine could be damaged. If heavy knocking is heard when using gasoline with a 93 octane rating, the engine needs service.
Prohibited Fuels
If the vehicle is certified to meet California Emissions Standards, it is designed to operate on fuels that meet California specifications. See the underhood emission control label. If this fuel is not available in states adopting California Emissions Standards, the vehicle will operate satisfactorily on fuels meeting federal specifications, but emission control system performance may be affected. The malfunction indicator lamp could turn on and the vehicle may not pass a smog-check test.
See Malfunction Indicator Lamp (Check Engine Light) 0 147. If this
occurs, return to your authorized dealer for diagnosis. If it is determined that the condition is caused by the type of fuel used, repairs may not be covered by the vehicle warranty.
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” in Fuel 0 292.
To keep fuel systems clean, TOP TIER detergent gasoline is recommended. See Fuel 0 292.
If TOP TIER detergent gasoline is not available, one bottle of GM Fuel System Treatment Cleaner added to the fuel tank at every engine oil change, can help. GM Fuel System Treatment Cleaner is the only gasoline additive recommended by General Motors. It is available at your dealer.
If your vehicle is able to use E85 or FlexFuel, GM Fuel System Treatment Cleaner - FlexFuel is the only recommended additive for use. Do not use any other additives with an E85 or FlexFuel vehicle. See E85 or FlexFuel 0 293.
Vehicles with a yellow sticker on the fuel door can use either unleaded gasoline or fuel containing up to 85% ethanol (E85). All other vehicles should use only the unleaded gasoline as described in Fuel 0 292.
The use of E85 or FlexFuel is encouraged when the vehicle is designed to use it. E85 or FlexFuel is made from renewable sources.
To help locate fuel stations that carry E85 or FlexFuel, the U.S. Department of Energy has an alternative fuels website. See www.afdc.energy.gov/afdc/locator/ stations.
E85 or FlexFuel should meet ASTM Specification D 5798 or CAN/ CGSB–3.512 in Canada. Do not use the fuel if the ethanol content is greater than 85%. Fuel mixtures that do not meet ASTM or CGSB specifications can affect driveability and could cause the malfunction indicator lamp to come on.
For the 6.0L V8 engine, after refueling, the vehicle calculates the composition of the fuel. It is not recommended to repeatedly switch between fuels. If fuels are switched frequently, add as much fuel as possible and do not add less than 11 L (3 gal) when refueling. Drive at least 11 km (7 mi) immediately after refueling to allow the vehicle to adapt to the change in ethanol concentration.
Because E85 or FlexFuel has less energy per liter (gallon) than gasoline, the vehicle will need to be refilled more often. See Filling the Tank 0 294.
If the vehicle has a diesel engine, see the Duramax diesel supplement for more information.
For models with dual fuel tanks, the fuel gauge shows an average of both tanks. The rear tank is emptied first. When refueling, refuel the front tank first, then add fuel to the
rear tank.
Filling the Tank With a Portable Gas Can
If the vehicle runs out of fuel and must be filled from a portable gas can:
The vehicle has a capless refueling system and does not have a fuel cap. The filling nozzle must be fully inserted and latched prior to starting fuel flow.
Be careful not to spill fuel. Wait a few seconds after you have finished pumping before removing the nozzle. Clean fuel from painted surfaces as soon as possible. See Exterior Care 0 430.
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