 The results on ethanol corrosion are in, and it's not pretty. Ten of the top automakers say unless you bought a flex fuel engine, they won't warranty ethanol damage. That's why AAA says don't use it. But most states mandate ethanol in every gallon, so you can bet it's in your tank now. There's a defense against ethanol corrosion. It's called BG Ethanol Defense and available at over 20,000 shops. Find one now at BGFindAShop.com. That's BGFindAShop.com. Remember these two letters. BG.