2011 Subaru Forester — accidentally added 15% ethanol gas

I question the ability of any mechanic that would make such a nonsense claim, and I’d avoid them.

Edit - at best, they completely misunderstood you and thought you were talking about E85.

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E15 will clean the fuel lines just as well as E10. You must have has a bad phone connection, the engine is not removed to drain the fuel tank.

I have drained E85 from customers vehicles and used it in my E10 vehicle, hate to see fuel wasted.

BTW, Auto technicians usually don’t answer phone calls, they have secretaries for that.

What’s the other half? If it was E10, then your tank has E12.5 now. (The oil and water comment is completely bogus.) That’s not ideal, but chances are that won’t cause any real issues. As mentioned above, try to add E0 as soon as you can.

Don’t worry about it, since it was only 1/2 tank, fill it the rest of the way with non-ethanol gas. More expensive than 87 octane E10, but cheaper ( in my area) than E10 premium.

And if you can’t find non-ethanol gas, I still wouldn’t worry about it, just fill it up with E10 in that case.


A year old post.

I wonder if the OP used up that tank of gas by now?


We’re responding to a new post.

No, they resurrected an old post rather than starting a new thread.

Thank you! I think that’s what I am going to do. I got ahold of a technician and he said to top it off with e10 every time I drive it. Idk how long I am supposed to do that for and I didn’t get to ask.

I think you misunderstood what they said or you asked the wrong question because the engine does not need to come out.

It was a relay of a message so it may have been a botched translation. The price was clear though. They told me that I needed to clean the engine lines out.

Just refill as you normally do, one tank of E15 will not have any affect on the vehicle.

I wonder if this is going to be the new version of diesel in the gas tank. :grinning:

I have purposely added E85 to my car to get to as much as 30% ethanol mix. Did absolutely no harm. The car ran really well as the mix has much higher octane rating. Like running super premium.

Any car built after about 2005 or so can use E15 or even E20 with no problems at all.

Your vehicle is likely designed for 10% ethanol gas, so the answer is: for the duration of your ownership.

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If the check engine light doesn’t come on you don’t have anything to worry about, not even topping off early.

Gas can be hard. Typical speedway, 91 noted as non oxygenated for off road use, Missed the boat guy and regular gas station, got Amsol fuel injector 2 cycle oil, ok for 50 to 1 mix it says instead of boat guy regular 2 cycle amsol oil, stopped by a speedway did 6 gallons premium but no note for non oxygenated gas. figure the boat will be ok, Things can get confusing.

ethanol content above 10% will add some skew into the oxygen sensors readings, so you might end up with CEL light illumining, but as you get E15 out of the system, it will eventually clear itself or you can force-clear it after you know most of E15 is out