10% Ethanol in regular unleaded gasoline

I have a restored 1940 Buick RoadMaster with a Straight 8. When out road testing, she will simply die after several miles, inspite of using an electric in line pump to augment the mechanical pump. She will restart and fire after pausing for several minutes to a half hour. This happens inspite of Stabil added to storage time or removing all the gas and refilling with new gas. It is suspected that the ethanol additive is causing corrosion to any and all of her rubber components in the fuel tank to intake manifold cycle (fuel level sensor, fuel pump, etc.). It has been suggested that instead of regular gas, I begin using either “Racing fuel” or “Aviation gas”, neither of which contain the Ethanol. I would ask any chemist or auto engineer if there is an available additive that can be added to our regular gasoline which can break down the etoh molecule? I am thinking of how does “dry gas” remove the h2o from the gas tank, sort of thing?

Thank You…I call it a HER because she is a beauty. 2 door convertible/black, with red leather upholstery.

We in Minnesota have had 10% ethanol in our gas since 1992. And have learned what ethanol can do to older fuel systems in classic cars, older small engines, and older marine engines. And because of this, we are able to purchase non-ethanol gas from gas stations.

Sta-Bil makes an additive for marine engines that reduces the corrosive nature of ethanol http://www.goldeagle.com/brands/stabil/products.aspx#marine_formula. I’ve never used this product so I can’t comment on its effectiveness. Other than this about all you can do is run non-oxy fuel in the vehicle.

The difference between ethanol and Dri-Gas is, most Dri-Gas products contain isopropyl alcohol which absorbs moisture and stays mixed in the gas to be burned off. Ethanol alcohol absorbs moisture also but doesn’t stay mixed in the gas. Instead it phase seperates out of the gas. This then causes the alcohol along with the moisture to settle to the bottom of the tank causing corrosion.


Maybe this problem is due more to an ignition fault rather than a fuel related one.

A faulty coil or ignition condenser can mimic fuel problems to a tee and the symptoms can be the same as what you’ve described.

I’d let it run until it dies and then quickly determine if a spark exists or not. (And it should be a strong blue spark. A failing coil or condenser may cause the spark to appear somewhat yellowish and/or erratic in the way it jumps a plug gap.

A failing ignition switch is another possibility. (Easily determined by checking to see if power is provided to the coil after it dies.)

How long does the gas sit in your tank unused? Gas with ethanol in it goes bad a lot faster than non-oxygenated (no-ethanol gas), it has a much shorter shelf life. If you don’t use a gas powered engine very often, don’t leave ethanol gas in the tank.

To add to Tester’s comment, we here in Minnesota learn this fact every spring when we have to take our lawn mowers out of storage.

I agree with OK…Many problems with old cars get blamed on ethanol when it’s really something else… Ethanol is not corrosive… But after long periods in an “open” (unsealed) fuel system, it WILL attract atmospheric moisture and become corrosive…

Sometimes antique cars that are rarely driven are better off with a secondary fuel system installed, a removable plastic marine tank installed in the trunk with a quick-disconnect fitting so NO Fuel is ever left stored in the steel gas tank. This way, the vehicle can be stored with the fuel system DRY…

If this car is still using the original 6-volt points ignition, that needs to be looked at carefully…

Thank you to those who replied: To begin with, I researched NW Ohio and there are no stations now providing gasoline free of the ethanol. In fact a very informed automotive contact of mine has heard that the ethanol % is climbing from 10 to as high as 40% in some areas.

  1. Stabil does make a product for marine engines that some how does reduce the corrosive effect of the ethanol, but reading their product description, it wasn’t clear as to how it was accomplished and to what degree.

  2. Speaking to another automotive “expert” (runs a very large independent shop for fleets, etc.) has a number of vintage autos and he unequivocably recommends that the addition of 1 container of “lead additive” (available at NAPA etc.) to a full tank of regular 10% ethanol added gasoline, will bind the ethanol and remove its harmful effects as well as providing the needed lead for the valve seats etc. It has “worked” on his vintage collection.

I started to take the fuel tank down today because the fuel gauge does not register with a full tank and I noted that there were paint bubbles on the underside of the tank and maybe the start of a microscopic leak. Also, I noted that on the top of the fuel pump alongside the engine block, there was corrosion and oxidation build up around the gasket to top seal. I am suspecting that the rubber diaphragm in the pump has been weakened or compromised.

Other than the aviation gasoline which is 90+ octane and does contain lead without the 10% ethanol at roughly 4.90/gal., what are other options, if any, not already discussed?

I would greatly appreciate any discussion on this issue.

Your symptoms are classic for a failing coil. Why are you convinced it is a fuel problem? The next time you take it out, drive it until it stalls,then spray a little starting fluid in the air cleaner.If it fires right up and stalls as soon as the ether runs out, it’s a fuel problem. If it doesn’t fire up it is a spark problem.

You don’t have other options.

The fuel system in your vehicle was never designed to handle any amount of ethanol gasoline. The corrosive nature of the ethanol will damage rubber and metal components of the fuel system.

I’ve been a member of the Minnesota Street Rod Association for over 30 years. And because we know the problems ethanol can cause to older fuel systems, we provide a list on our website to those who drive classic vehicles where they can get non-oxy gasoline. http://www.msra.com/NonOxygenatedFuel/Non%20Oxy%20List%20-%20August%202010.pdf So you have three choices. Find non-oxy gasoline, find an additive that reduces the corrosive nature of the ethanol, or be prepared to replace fuel system components on a regular basis.


The two main areas where ethanol might cause problems would be the rubber diaphragm in the fuel pump and the rubber flex hose(s) between the fuel tank and the steel fuel line to the pump and the flex hose at that connection. Replacement parts (if you can find them) should be made from materials that can tolerate the ethanol…

Depending on how much you drive this car, the expense of using aviation gasoline should not be that big a deal. Another benefit, av-gas will not vapor lock. The down side is difficult cold weather starting because of the very low vapor pressure. A shot of ether might be necessary on cold mornings. You can not pump av-gas directly into a car. That’s illegal because no road tax has been paid. So just buy 20 gallons in 5 gallon cans labeled “off-road-use-only”… Look for LL-100 grade fuel. Back when I was young and foolish and road-raced motorcycles, that was how we obtained decent fuel…

Thank You one and all: I will try your suggestions. Any word on the lead additive to the regular gas?

Lead additives and octane boosters are different things.

In the days of your vehicle, the tetra ethyl lead in gas served two purposes. It was an octane booster and a lubricant for the exhaust valves. This is why when someone has a classic engine rebuilt, they make sure hardened valve seats are installed for the exhaust valves if they plan to run unleaded gas.

These lead substitutes for exhaust valve seat wear work good, if you don’t run that old engine too long and too hard.


Tester: Thank you…does the lead additive have any effect on the ethanol? My friend with the classic cars intimated that it bound the ethanol to ? and blocked its corrosive action. I dropped the fuel tank today and found the float for the gas gauge rusted with a large hole at the seam. I assumed it was some sort of brass material. All kinds of particle soot blown out of the exit line. There is an inline filter before the fuel gets to the mechanical pump and I am surprised that it allowed to soot to get to the carb. Any comments?

Water mixed in alcohol at these amounts simply does not do this. The “phase” separation you refer to is not significant in a car simply driven once a month and the moisture build up in a car of this age is due to an unsealed fuel system. Ethanol is not a suspension in the gas like salad dressing, that is just nonsense. If this was true in any case why does the top of the gas tank rot out first? Replaced a bunch in 30 years about to do another and the bottoms are shiny on the inside and the tops are toast.

No. I’ve never seen an additive until the Sta-Bil marine application that claims to reduce the corrosive nature of ethanol. So we in the MSRA have never seen a octane booster or a lead substitute that stems the effects of ethanol.

If your brass gas tank float is corroded away, you might want to check the brass carburator float(s)are also damaged.


Tester: Thanks again. I am pulling out the entire fuel system from the tank to the mechanical pump to the carb and breaking them all down. I bet the floats in the carb are in trouble too and as soon as I disassemble, I’ll report their condition. I already see a few rust spots inside the tank and there are a few paint bubbles on the outside and I bet these are micro holes from the rust. I am thinking of finding me a junked plastic tank as a replacement. What is the record on the liquid pour-in liners to prevent further decay/rust in the tank? Does this stuff ultimately fragment from the ethanol and particulize(sp?) and and get to the carb nozzles? Or should I start from scratch and find a new tank and keep going with the Av gas?
Thanks Again

According to the list at the bottom of this site, Ohio is not a mandatory 10% ethanol blending state.