Automakers are going to great lengths to get more miles per gallon from their vehicles and everything is being looked at -- even the engine oil.
Every 2011 General Motors car rolls off the assembly line with the engine filled with a new generation of oil. Other automakers, such as Ford Motor Co. and the Chrysler Group, are also beginning the switch to new oil, known by its industry grading as GF-5 or SN, or, in GM's case, Dexos1.
GM says using the wrong oil may cause engine damage that would void the powertrain warranty.
The grade identifies oil that's designed to help engines run more efficiently and better protect them from wear. Those are key properties as automakers wring more horsepower out of smaller engines and make greater use of heat-producing turbochargers and superchargers.
The protection properties of the new oil also have the potential environmental benefit of increasing the mileage interval between recommended oil changes.