Professional Quality Products

Home Up Feedback Contents Search Links Page




Gasohol Ethanol Blended Gasoline

How to Prevent Storage Problems


Image Courtesy of JME Sales

One of the biggest problems with gasohol (Ethanol blended Gasoline) is that it is extremely hygroscopic (the ability to attract water molecules from the surrounding environment and to hold them either through absorption or adsorption.

E-10 Gasohol (Gasoline containing 10% Ethanol) can hold up to 3.8 teaspoons of water in solution in the fuel. This water can lead to corrosion, poor economy, drivability problems, and to phase separation leading to other much more serious problems.

To combat this hygroscopic problem it is vital that storage tanks be purged of all water before any fuel containing Ethanol is added. The use of dispersant additives to deal with any residual water is also beneficial.

Storage tanks will pick up water from condensation of moisture in the air due to the daily changes in temperature. A large storage tank can actually generate anywhere from several ounces to as much as a gallon of water per day. Normally this water would settle to the bottom of the tank; however the Ethanol will pick it up, blend with it, and hold it in suspension.

The addition of a Desiccant type filter in the vent system will dramatically reduce or eliminate this condensation. While this idea is relatively new in the US many other countries mandate the use of these filters to prevent water problems.

It is also vital to regularly check the storage tank with water finding paste to be certain that there is no separated water on the tank bottom. Another advantage to water finding paste is that it will begin to slightly change color or in some cases small colored dots will begin to appear on the paste. This indicates that the fuel mixture is approaching the saturation point where phase separation will happen.

Note: Many of the electronic monitoring systems used for tank water detection may not register properly with Ethanol blended fuels. Also we have seen many instances where the fuel tank sending unit becomes saturated with water and stops functioning properly. When this happens the device will show the last good reading indefinitely.

It should be expected that tanks containing Ethanol will require a significantly higher level of maintenance than those holding regular gasoline or diesel.

Diesel Doctor

Copyright 2009 - William Richards


Hit Counter

Send mail to: with questions or comments about this web site.
Last modified: 04/06/09
Copyright: 2008, 2009 LCBA Marketing Group