My son put E85 fuel in his 2009 Ford Focus. Will it cause damage?

[Anonymous]

When he realized his error, he drove straight home, approximately 5mi. He said it ran fine but wonders if it is okay to run like that or if he should syphon it. It was about 5 gallons and he was on empty when he put it in. Any help is appreciated!

[CrazyGirl2]

The ethanol in the E-85 has a corrosive action on fuel-system components, magnesium, aluminium and rubber. Running E85 on older model engines without tuning the motor and replacing all aluminum & rubber fuel system components will ruin the engine in short time. Since this was a one time thing, and it was only 5 gals, it’s doubtful any noticeable damage will appear in the fuel tank or the aluminum fuel lines, and injection fuel-rails, but any rubber (black) o-ring gaskets in the fuel system are going to begin breaking down first, and start leaking. After that it’s only a matter of time until you will need to replace them… ALL! Actually, since most of the corrosion/disintegration of seals occurs when the car is parked as the ethanol is just sitting there against rubber seals, quickly dissolving them, parking it was the worst thing you could have done, but if I didn’t know, I’d likely do the same thing!
As far as your car specifically, it’s difficult to tell the level of damage E85 would do in one 5gal instance and you’ll probably be fine. But I would definitely siphon it out and put a full tank of good gas. Also talk to your family mechanic about it. That’s about the limit of my knowledge. I’m most certainly not a mechanic, but I’ve been building and restoring cars with my dad since I was a little girl, and I actually built the corvette engine in my Jeep, and I definitely remember when he decided that I should use polymer o-rings of this very reason. He explained what ethanol does to aluminum, magnesium, and rubber, and since he had no idea if fuel companies would be required to use more and more ethanol in their fuels, he thought a small cost now beats replacing the fuel system later.
I do hope that helps, Laura.
here’s a good source: https://fuelandfriction.com/weekend-warrior/e85-dont-do-it-unless-you-know/

[Asker]

That's what sucks! I have a mechanic but he's closed (July 4th). You were helpful, thanks. Right after he called me I goofed it and the link you sent me came up but other links I read said it's not that big of a deal. I'll wait until tomorrow and give him a call.

[CrazyGirl2]

Sorry to hear that. Yeah I had to google it too, although I am pretty smart, even I cannot remember EVERYTHING my father ever taught me. And I didn’t want to give you bad advice! I absolutely knew the ethanol dissolved rubber seals like o-rings, but I wasn’t sure how quickly it would effect the motor, nor how badly. The best thing you can do now to mitigate the damage, is siphon any remaining E-85, and replace it with about 2gals brand name fuel, then when it is completely empty as in on the side of the highway, pull the 5gal container of good brand name fuel from the trunk and put that all in the car and drive home. You need to basically wash the fuel system ASAP!
Good luck, and I’m glad I could help, Laura.

[Asker]

I talked to my mechanic today. Fortunately the 2009 Focus has some of the same engine components as cars that actually run off E85. Obviously it's not certified to run on it but a one time oops isn't gonna cause any damage. He basically said fill the tank with reg. unleaded to lean it out and run it normally. BUT, you are 100% right! Any Focus pre-2007 would be an issue. Like you said, they don't have the proper components and it would have been extremely corrosive! Your dad taught you well! Thank you for your help. I thought I'd fill you in because I thought you'd like to know. I found it interesting and a HUGE relief.

[CrazyGirl2]

Thanks for the update! I’m really glad that I could be of help. Yes, I thank god for being lucky enough to have such amazing parents. I’ve seen how the parents of some of my friends are, and I feel even more lucky!

[Asker]

You helped a lot! I went in asking questions about the corrosive damage E85 can do, because a "friend" told me. That's when he told me that pre-2007 didn't have the engine components but a 2009 standard 4 cylinder Ford Focus, along with a few other vehicles, were manufacturered to run with that type of fuel for a period of time without causing damage. I'm not a mechanic and no one in my family is! We have a doctor, a couple lawyers but no mechanic. Lol Every family needs a MECHANIC!

[CrazyGirl2]

My dad’s not exactly a mechanic, he owned a software company that invented something that makes CGI look more realistic. He sold the company to Disney/ILM, and now he works at Disney, but he has a love of cars and a huge car collection. It’s always been his passion.

[DryGermanGuy]

This is a standard four cylinder engine, without turbo or compressor, right? Nothing will happen. Just drive normally and top up the tank two or three times with regular fuel.

[Asker]

Yes, it's just a normal 4 cylinder. Right now it's half a tank, I was wondering if it would hurt to fill with regular unleaded?

[Asker]

Also, he looked at the gas cap and there was an E85 with an X over it. If that means anything to you. Lol

[DryGermanGuy]

Mostly it’s a liability thing, the engine is not certified for E85.
Just top the tank off with regular unleaded and do not drive it like a race car till it’s empty again.

[Asker]

I am so glad to hear that! Thanks.

[dudeinohio]

Oh... if it's only half a tank, top it off and call it good. Zero chance of anything bad happening.

[Asker]

@dudeinohio Yeah, at $5 a gallon he can only afford about $20 worth at a time! Lol That's why he put E85 in. It was only 3.72 a gallon but when he was driving away he noticed the pump he was at was the only one that had it. So he figured something wasn't right. I told him fill it with regular unleaded and I give him the money for it. Thank you guy's. You put my mind at ease.

[dudeinohio]

You'll be fine. You may get a check engine light; but that'll go. out, once you've begun replacing the e85 with regular fuel.

[Asker]

He said it ran fine. About how long would it take to show problem signs?

[dudeinohio]

With just one tankful, it may not show any signs. If it runs fine now, it's likely no problems would show up. I had a Ford Windstar van I'd fill up with E85 deliberately every so often and I never has a problem.

Still, long term use in a car not designed for it could possibly cause damage to any rubber components in the fuel path. One tankful wouldn't be enough to cause physical harm.