Your Classic Car and Ethanol

Ethanol—a word that sparks much controversy these days. It’s not a new word or concept. Ethanol the consumable liquor has been around in the form of Moonshine Whiskey since 15th Century Scotland. Ethanol the fuel was used in the Ford Motor Company’s first car, The Model T, back in 1908. Nonetheless, the conflict on the topic of Ethanol for fuel is a heated one…no pun intended.

Regardless of where you stand on the economic viability of ethanol, the fact remains that bio-fuel is becoming ever more present at our pumps. According to, ten states have enacted Renewable Fuels Standards that require the use of ethanol-blended fuel, twelve states have some type of retail pump incentives for ethanol, whether for E10, E85, or both types of ethanol-blended fuel, and twenty-two states have some type of incentive for ethanol producers. Click here for the full listing of states. All of which begs the question, “What effects can Ethanol have on my classic car?”

While we aren’t scientific experts on the subjects, we happen to have a few classic cars of our own and at least have some experience on the topic. We have also done some research so that you can use this blog post as a place where you can find some interesting takes, facts, and myths regarding the use of Ethanol in our classic cars—and just plain cars in general.

We think it is a pretty well known fact that at the very least ethanol can damage some parts of the fuel system, especially on older vehicles and engines, which were never built with the effects of E10 in mind. The effects on car engines could seldom be described as “disastrous,” but rather border on “real pain.” Aside from Ethanol burning hotter than gasoline, causing catalytic converters to break down faster, Ethanol will eventually cause rubber fuel system components to deteriorate and contaminate the fuel system. The list of items could include hoses, needle tips, some carb floats, fuel pump diaphragms both mechanical and electric—and that’s just to name a few. We are interested to see what happens to the older fuel tanks that have been coated with sealant. While surely today’s fuel tank sealers are meant to withstand wear from ethanol, some of the early material was not. Man, if that stuff dissolves and makes its way to carburetor, someone is going to have a real mess on their hands.

All of that being said, minor updates and maintenance on your collector car will help protect it from the effects of modern fuels. I have my own set of beliefs and general practices that get me through based on what I have read and good ole common sense:

  • In general, I always start my cars frequently, if for no other reason than to at least get the engine to operating temperature and move fuel through the system. Of course, the more you drive your car, generally the easier the maintenance.
  • If your collector car is still in its original condition, consider replacing seals, gaskets and fuel lines with modern replacement materials since older fuel system components are often incompatible with ethanol-blended fuels.
  • If it becomes necessary to replace fuel lines and other fuel system components, anything created after the mid 80’s will more than likely be suitable to contend with today’s fuels. If you want to believe the Renewable Fuels Association, preferred materials are Viton and fluoroelastomers such as Fluorel.
  • Thereafter, once or twice a year closely check fuel hoses, fuel pumps and carburetors for any leaks or contamination.
  • Be sure that you are using a 10-micron fuel filter and have spares on hand because you want to change it more frequently than usual. Ethanol is a solvent that dissolves resins, rust and dirt that have accumulated on older tank walls. This is especially important when first making the conversion to E10.

 Storing your car for more than 30 days:

  • Before you do anything, make sure your fuel tank is as clean as possible with no sediment or sludge. This can cause fuel system problems when you go to start her back up since over time ethanol in the fuel tends to re-liquefy the varnish from the bottom of the tank (as we mentioned above).
  • One you have a clean tank, be sure your tank is full of gas. Ethanol is alcohol and will attract/absorb water into gas resulting in phase separation of fuel. The best way to prevent phase separation in E-10 is to keep it dry! That means keeping the tank filled to prevent condensation.
  • Keeping any gasoline, including E10, as fresh as possible is very important. Mixing in a fuel stabilizer is a good habit to maintain since modern fuels break down faster than gasoline of the past.
  • I’ve gotten in a habit of adding Stabil to everything I own that uses Ethanol, aside from my daily drivers.  This includes my weed eater, leaf blower, chain saw, boat or anything else that may have fuel sit for weeks or months.

If you have an input, general practices or stories, feel free to add them to our comments section. We are very interested in what you have to add to this conversation.

In the meantime, check out some of the sites and articles we looked at to back up our info:

Hagerty’s collector car insurance Ethanol study results
Renewable Fuels Association Report on Ethanol and Classic Cars

Bloomberg on the Myth’s and Realities of Ethanol
Q&A from Hemmings Motor News excerpt

Ethanol free gas stations in the US, listed by state



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