E10 Gasoline and Antique Vehicles
Gasoline as we knew it from the old days is gone…. replaced by the more modern substitute which is minus the lead and minus the MTBE additive. Those long time additives have been replaced by alcohol, and other “green” additives, to make today’s gasoline more cleaner burning and better for the environment than the gasoline of old. But what about the older vehicles built before 1980 that were designed to run on the old formula gasoline…how are they affected. Well here is what you need to know….

Some Background:
Beginning in the early 1980’s the federal government passed into law environmental rules that would change the way automotive gasoline is made. This… while the demand remained to provide gasoline that performed to the standards in drivability that we were already used too. The new government standards did not designate how the new gasoline was to be made or what it was to be made of… only what environmental standards it had to meet.

Most all of the oil companies came to the same conclusion… that in order to meet the new more strict government environmental standards, adding alcohol to the gasoline is the most cost effective solution. So adding alcohol along with a few other “green” additives…is what you are buying at the gas pump today. Gasoline with ten percent alcohol, known as E10 is now sold in most all locations within the United States by federal law.

When E10 was first introduced back in the 1980’s the gas pumps were required to be labeled so you knew which pumps were selling E10 and which were selling regular gasoline. This time around things are different, with the government mandate, most all pumps are selling E10 and in most cases the pumps are not labeled, as there is not a choice. Only the pumps selling gasoline with greater than ten percent alcohol must be labeled. You will know the alcohol is there because you can smell it.

Depending on where you live, there are over forty different formulas for gasoline. Some formulas are determined by the federal government, some by state government, some by local cities and counties. The different formulas all have a different shelf life.

Vehicles 1980 and Newer…
Vehicles built in 1980 and later should experience very little negative effects from E10 gasoline in their fuel systems. You need confirm that any aftermarket fuel related components (gaskets, hoses, etc) you buy at the auto parts store for your vehicle is made of the modern alcohol resistant materials, instead of just plain rubber, so those parts should not be affected by the alcohol.

Vehicles Built Before 1980
For the rest of us that drive, antique vehicles built before 1980… here is what you need to watch out for and fix. Much like the change in motor oils when the Zinc additive package was quietly removed (see modern engine oil on tech tip pages) there are some areas of concern you need to be aware of.

Rubber Hoses-

Rubber hoses, including fuel lines are subject to damage from the alcohol in the E10 gasoline. The gasoline will cause the hoses to become brittle on the outside, soft on the inside, in a fairly short time, which could result in a leak and possible fire hazard.

Plumbing-
Steel, aluminum, and some other metals… E10 gasoline can be corrosive to aluminum and some alloys. Also fuel pump diaphragms, fuel pump gaskets, rubber washers in fuel pumps and carburetors, etc. are subject to damage if those parts were manufactured before 1980. Watch for damage in places like 90 degree bends in fuel lines.

Mechanical Body Parts-
fuel pump housings, carburetor housings, metal filters, and related parts be subject to etching from the E10 gasoline. Watch for pinhole leaks where the metal is thin.

Cleaning Effect of E10 Gasoline
The E10 gasoline will act as a strong solvent… so things like carburetors, fuel pumps, jets, floats, accelerator pumps, and internal components will become very clean. This “solvent” effect may loosen gum and varnish deposits that will then plug fuel filters and carburetor passages on a regular basis.

Fuel Tanks-
the solvent cleaning action of E10 gasoline can also result in varnish removal from the inside of the fuel tank as well as causing corrosion and rust to form on the inside walls of the fuel tank. You may notice this as a clogged fuel screen that you have to clean repeatedly or the fuel screen that may disappear completely… dissolved by the alcohol. Rust formation inside of fuel tanks occurs quicker in high humidity conditions and when there are extreme temperature changes…unheated storage areas for example.

Filters-
Fuel filters may clog more often as the inside of the fuel system gets a good cleaning. Also watch for any rubber components that may be deteriorating, with the tiny pieces getting caught up in the fuel filter.

Water Phase Separation:
E10 gasoline will also attract moisture from the atmosphere thru places like gas cap vents. Water is heavier than gasoline so the water molecule is dragged to the bottom of the gas tank where it then separates from the more buoyant gasoline molecules. A gallon of E10 gasoline containing 10% alcohol can suspend nearly 4 teaspoons of water per gallon. Temperature changes and humidity can speed up this process. Keep that in mind if you are placing your vehicle in storage for an extended period of time.

Off Season Storage:
E10 Gasoline is typically stable for a period of 90 days under ideal conditions but may already be 30 days old when you purchase it at the gas pump, therefore if you are storing your vehicle for a period in excess of 45 days you should store your vehicle with a full tank of gasoline and add a fuel stabilizer. Be sure the fuel stabilizer you add is nonalcoholic. Gold Eagles "STABiL" seems to work well.