Ethanol can impact your engine in several ways, depending on its concentration in the fuel and your vehicle’s design. Here’s how it typically affects your engine:
Positive Effects:
- Cleaner Emissions: Ethanol burns cleaner than traditional gasoline, reducing greenhouse gas emissions and air pollutants.
- Higher Octane Rating: Ethanol increases fuel’s octane level, which can improve engine performance and reduce knocking in high-performance engines.
Negative Effects:
Compatibility Issues: Older vehicles and certain small engines (like those in boats or lawnmowers) may experience problems when using ethanol blends, especially those with higher concentrations (like E85).
Fuel System Corrosion: Ethanol is more corrosive than gasoline and can damage older engines that weren’t designed to handle it. Rubber seals, gaskets, and fuel lines may deteriorate over time.
Lower Energy Content: Ethanol contains less energy per gallon compared to gasoline, which can lead to slightly reduced fuel efficiency.
Water Absorption: Ethanol is hygroscopic, meaning it attracts water. Water contamination can lead to engine performance issues, especially in vehicles left unused for long periods.

