BioDiesel and E85 are two very different fuels. BioDiesel is diesel fuel made from organic sources such as vegtable oil, etc. E85 is a gasoline product with up to 85% ethanol in it as opposed to up to 10% ethanol found in regular unleaded gasoline.

Diesel fuel is similar to kerosene.

E85 can damage fuel systems that were not deigned for it. It attacks common rubber and elastomer parts. Metal corrosion is a another problem. The materials for E85 service must resist both ethanol and gasoline at the concentrations found in E85.

So, which dod you put in? E85 or Diesel?

If you put in only a gallon of diesel, then diluted it right away with regular unleaded gasoline, you may not notice much difference and I think that no damage will occur so long as you refrain from pushing the engine to its limit. Diesel lowers the octane rating, and therefore increses the potential for pinging. Diesel is not as volatile as gasoline and may produce hard starting in cold weather.

Hopefully, you did not put much E85 in. If it was a half gallon or so, diluting it immediatly was the proper move. If you put in 3 or 4 gallons, it should be drained.

If you are really lucky, you car is E85 capable and there would be no concern at all. Check your owners manual for fuel capability.

Hi Beth

A little e-85, even if your car does not use e-85 won't hurt as long as you diluted it with regular gasoline. Today's gasolines "average" 10% ethanol so essentially all you did was bump that percentage a couple of points. Your car will handle that just fine based on the fact that you say you only have a few more payments to make on it, I would expect it to be designed to tolerate ethanol. That would mean BTW, most cars since around 2000 model year. Now E-85, otherwise known as "Flex Fuel" vehicles can run regular unleaded fuel, E-85, or some blend of the two. The car can litterally figure out exactly what the concentration of alcohol vs gasoline is in the tank and compensate for it. If you happen to own one of the certain Ford, GM, or Chrysler vehicles, your car may in fact be designed to run on E-85.

BTW, around here I do not know of anyone actually selling bio-diesel. There are people who are making their own, and the long term effects of bio-diesel as in used french fry oil on the delicate injection components is something that is actually not well known, and a major concern. But again that is diesel anyway, the nozzle should NOT have fit into your fuel tank inlet. You would have noticed that right away, so it can be inferred that if you didn't put regular gasoline in, then it had to be E-85.

So do you own a; Ford Ranger? Taurus? Escort? Chrysler Minivan? Intrepid or about half of the GM line of cars and small trucks? Is there a decal on your car that looks like two tea leaves? Check the area inside the fuel cap cover for a decal that say's e-85, and/or the owners manual for the car. If pricing continues to rise as it has, E-85 will soon be a bargain compared to regular fuel, but only people with E-85 vehicles will get to take advantage of it.

OK. Here's the update. I did check my manual and it said that I could use different blends of fuel but it said that the alcohol content should be no more than 10%. But, it did say I could use different blends so I think that is a plus. It gave a bunch of other requirements and numbers, but I'm focusing on the fact I could use different blends as a good thing. I am really confused by the bio-diesel or e-85 thing. I probably misread something on the pump but at newer Meijer stations they do have both sometimes. I checked their website and the one I went to does have both. But on the pump it said bio-diesel in green on top. But lower on the pump there was a sticker and I swear it had an e85 on it and said something about a low sulfer (I think it said sulfer) fuel. But, that was half an hour away from home and so I can't really be too sure which one I used since the station had both. I don't understand why the pump said bio-diesel and had a sticker with E85 on it. Like I said, it was late and I was obviously not focued too much since I pulled up to the wrong pump in the first place. But since the top of the pump said bio-diesel then I'm going to go with it being bio-diesel which I know means that it doesn't really matter that my car can use different blends. But, I drive a 2004 Beetle so it is fairly new and in very good condition. But, I did dilute it right away with half a tank of regular unleaded. Then I filled up and drove it the following morning for about half an hour. I got a bottle of fuel system cleaner and put in and drove it down to half a tank. I'm going to fill up again today and drive it down to another half a tank and fill it again and put in another bottle of the fuel system cleaner and then drive it until it's at about a quarter of a tank and then fill up and hope it's all out of the system by then. Good plan or no? And just to refresh, I did only put in a little under a gallon of whatever it was and immediately dillute it. And so far, there has been absoultely nothing out of the ordinary. No smoke, no odd sounds, no smells, no driving hard, starting up just fine. But thank you all for your advice!

ps. Does anyone know if a bio-diesel nozzle is the same as a regular diesel nozzle? I'm hoping that you are right, John G, and that a diesel nozzle shouldn't have fit in my tank. But the nozzle looked like any other nozzle and went in the tank just fine. So, I'm glad I noticed the signage on the tank pretty quickly. I feel like such an idiot about this whole thing.

The nozzle for diesl is bigger then the nozzle for gas.Will not fit in the hole.I would be more concerned about buying gas at Meijer gas station?I avoid stores that sell gas like Walmart or gas stations with names like Freds quicky stop.Hard telling where they get there supply and how much they water it down so they can be a few cents cheaper.

Water it down?

Sorry that's an old wives tale based on the fact that the fuel is stored in underground tanks and condensation can occur as fuel is dispensed, and the occasional (used to be that is) inlet of water from a heavy rainfall could add to the condensation level. Water is heavier than gasoline so it sits at the bottom of the tank undisturbed except for when the tank is first getting filled. There is a special chemical that gets applied to the "dip stick" that allows the attendants to measure water accumulation, and then when there is a given amount a company is hired to remove it and purify it before it gets released back to the environment.

If you attempt to add water to today's fuel, which is 10% ethanol, it will pull the alcohol out of solution and both the water and alcohol will fall to the bottom of the tank. We use this principal to test alcohol content of a fuel when we suspect a misfueling has occurred. Which BTW leads back to another myth. "Dry Gas" does not make the water that is in someones fuel burn. It only makes it not freeze as easily.

I put E85 in my brand new 2009 Chevy Cobalt thinking it was cheaper 85 octane gas. Was on a 500 mile trip home, 200 miles in, check engine light came on, remote start wouldn't work.Used entire tank of gas, filled up with regular 85 octane next time and continued home. Next day, light was still on, remote start still wouldn't work. Later that day, engine light went off, remote start worked. I say DON'T worry if you do this ONCE!!!!