There has been a lot of discussion recently on vehicle warranties, which can be a complicated question for new fuels like E15 (15 percent ethanol, 85 percent gasoline). To start with, E15 is approved by the Environmental Protection Agency (EPA) for vehicles 2001 and newer. But, this higher-level fuel blend was approved by EPA when many of the vehicle owner's manuals were written. There has been significant growth in the inclusion of E15 in new vehicle owners manuals since EPAs approval in 2011; especially for brand new cars and trucks sold from 2012 to 2014. In fact, more than 70 percent of the top-selling cars are approved by the automaker for E15 usage in their 2014 vehicles, including certain makes and models of Ford, GM, Volkswagen, Honda, Toyota, Mercedes-Benz, Jaguar and Land Rover. New owner's manuals may provide guidance on the use of E15, but that leaves car owners questioning older vehicle model's use of E15 and the effect, if any, it will have on the validity of the remaining warranty coverage. Just like aftermarket fuel additives, like stabilizers and octane boosters, or the economy-grade 85 octane gasoline that is offered in mountain areas, specific fuels or additives are not always called out by name in a vehicle owner's manual. Use of these non-mentioned fuels and fuel additives does not necessarily void a vehicle warranty. In fact, vehicle manufacturers may not deny a warranty claim based on use of a different fuel if that fuel did not contribute to the problem for which the warranty claim is made. But the truth of the matter is that E15 is the most tested fuel additive in EPA history. It has been on the market for 19 months and driven more than 60 million miles with no known cases of engine damage or liability claims against fuel retailers, blenders, refiners, automakers, or ethanol producers for E15 issues.