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 for additional information.
Gasoline Octane
California FuelChevrolet Cobalt Owners Manual. Engine Oil Life System
When to Change Engine Oil
This vehicle has the Engine Oil Life System, a computer
system that indicates when to change the engine oil
and filter. This is based on engine revolutions and
engine temperature, and not on mileage. Based on
driving conditions, the mileage at which an oil change
is i ...