An Alcohol Fuel Test Kit will give you the data you need to keep engines safe with E10 gasoline.
E10 Gas has a shelf life of only 3 months.
Gas Expiration - Ethanol Blend Fuels Have a Short Shelf Life
Ethanol alcohol fuel blends have a shelf life of only 90-100 days, under ideal environmental conditions.
When exposed to water, E10 gas will contaminate and should be discarded.
Only 1 tablespoon of water/per gallon will cause fuel to contaminate/separate!
Replace gas in your fuel tank every 2-3 weeks to avoid alcohol and water related engine problems.
Monitor and Test gas for alcohol and water content frequently.
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Several factors affect the shelf life of ethanol blend gasolines...
Gasoline blends without ethanol, have a shelf life of many years. The shelf life of E10 is lower due to ethanol's affinity to attract and absorb water.
The public has not been properly educated in the changes in fuel system management since the switchover to alcohol blends of fuel.
Even many gas stations owners, do not realize that E10 is expired (bad fuel) only after about 90 days from the date ethanol was added to the gasoline.
Often when tanks are not properly serviced before switching to ethanol blends of fuel, the water present at the bottom of tank will immediately contaminate the new E10 gas added.
All gas supplied to the public contains preservatives - But this perservatives and stabilizers do almost nothing to prevent water contamination.
Foolishly, many consumers are adding extra "additives" to their gas tanks that sometimes deceptively claim they will prevent ethanol water absorption - No product/additive with this capability exists.
Several additives/products may help with the undesireable side effects, due to ethanol chemical properties (drying agent, solvent, etc.) -
No product exists that will prevent water absorption by alcohol.
All alcohols have a natural affinity for water. By nature, they attract and absorb moisture.
Whether or not the alcohol is in a medical, cleanser, beverage or fuel - All alcohols attract water.
It's the "water absorbing" properties that makes ethanol gas most problematic and difficult to manage.
- Petroleum does not blend with water.
Therefore, when excess water enters fuel supply, gasoline will phase separate.
- Phase-separated gas is contaminated and should never be used in engines.
Not only does separated fuel create obvious problems, (E.G. poor performance and release of water into engine) when phase seperation of the water level is introduced into engine; Water in fuel distorts the hundreds of other ingredients that gasoline contains.
- Water-contaminated and phase-seperated fuel will experience a drop in octane.
Click here for information on OCTANE of ethanol fuel blends.
- Ethanol gasoline is hygroscopic (will absorb water) and can absorb 50 times more water than conventional non-alcohol gasoline.
- Phase separation occurs in E10 gas, when only 0.5% water or 3.8 teaspoons water per gallon of fuel is absorbed.
At 70 degrees Fahrenheit, conventional (non-alcohol) gasoline can dissolve up to 150 parts per million (ppm) water.
The situation is different for gasoline oxygenated with 10 % volume ethanol...
The ethanol blend can dissolve much more water, up to 6000-7000 ppm.
When this blend is cooled, both the water and some of the ethanol become insoluble.
With the process of phase separation, two layers of liquid are visible.
An upper ethanol-deficient gasoline layer and a lower ethanol-rich (up to 75% ethanol) water layer.
It occurs because ethanol is completely soluble in water but only marginally soluble in hydrocarbons...
After phase separation, the gasoline layer will have a lower octane number. The fuel also is less volatile.
When using fuels that contain alcohol/ethanol, special precautions are necessary to prevent contamination by water.
The amount of ethanol blended in at the pumps, is not closely monitored.
The ethanol is not added at the major refineries - Usually it is the delivery truck driver who adds the ethanol to fuel supply.
Checking that gasoline meets safe and legal alcohol guidelines (10% or lower), seems recommended, until more stringent and protective laws are passed.
Refilling often, with high quality, fresh gasoline, is the best measure you can take to manage the shorter shelf life and higher risk of water contamination that occurs when using E10 and other alcohol fuel blends.