I searched and saw Dough's thread discussing Etanol so consider this a follow up to his thread. I got sent an e-mail from my local BMW stealer with some valuable info regarding Ethanol that I wanted to share. Goes as follows:
Ethanol and your BMW
The recent addition of ethanol to gasoline in the US gasoline has sparked a lot of discussion among our customers. Since these issues are of common interest to many of our customers, BMW of Stratham wanted to take a moment to offer some suggestions for your 330ci.
What Is The Current Use Of Ethanol?
As you know, Ethanol is a fuel additive that, in the US, is usually made from corn. When burned, ethanol releases much less tailpipe emissions than gasoline, making it better for the environment. Because of that, ethanol is now being mixed with gasoline for auto fuel. This mixture can be from 10% all the way up to 85% (E85).
Will Using Fuel Mixed With Ethanol Harm My Vehicle?
Using a fuel that contains up to 10% ethanol will not harm your vehicle. However, there are a couple of things to be considered. First, under some conditions (usually low temperatures) ethanol separates from the gasoline-alcohol mixture and absorbs water. The ethanol absorbed water is heavier than gasoline or ethanol and settles at the bottom of the fuel tank. When introduced into the combustion process, this leads to an extremely lean fuel mixture and can result in misfires, rough idles, and cold starting problems.
Secondly, some materials commonly used with gasoline are not compatible with ethanol. When these materials come in contact with ethanol, they may dissolve in the fuel, which may result in poor drivability, or worse engine damage.
Please remember that fuels that contain more than 10% ethanol such as E85 are intended for specially prepared vehicles (flex-fuel vehicles). These fuels must never be used in BMW vehicles.
Will Using Ethanol Void My Warranty?
Using fuel that contains up to and including 10% ethanol will not harm your vehicle or void the applicable warranty with respect to defects in materials or workmanship. However, BMW does not cover damage caused by fuel containing more than 10% ethanol or by contaminated fuel.
What Can I Do To Protect My Vehicle?
There are a couple of important things you can do to protect the investment you've made in your BMW.
1. Purchase high quality fuel. Make sure that your fuel has a minimum octane rating of AKI 91 and the percentage of ethanol is 10% or less.
2. Purchase your fuel from a reputable source. BMW and several other auto manufacturers have worked with gasoline retailers to approve "TOP TIER Detergent Gasoline". These fuels have increased levels of detergent to help keep engines cleaner and reduce deposits-related concerns.
You can find out more about TOP TIER Fuels and find a retailer at