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post #1 of 4 (permalink) Old 10-22-2017, 10:10 AM Thread Starter
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E85 in My 2008 Chevy Cobalt LT

Hi there everyone, I'm here to learn about my 2008 chevy LT Cobalt. as of this last friday the 10-20-2017 I filled up my gas taken with E85 thinking it would be okay because it is a 2008. It has always ran on 87 but I wanted to try E85. But as of yesterday 10-21-2017 my engine light came on and the only thing I have done to it is put that E85 in it. I have not heard any knocking noise yet and my egnine is a 2.2L L4. My question is, can I run this gas out of my car on my daily drives to work and home, or should I drain the gas out of my car and fill back up with 87? I dont want to ruin my car after I just got it fixed last week.

Last edited by Coby7; 10-22-2017 at 10:50 AM.
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post #2 of 4 (permalink) Old 10-22-2017, 10:53 AM
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Does your manual say you can use E85? Normally you would have the FlexFuel logo on there if yes. Hope you didn't already hurt something...

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post #3 of 4 (permalink) Old 10-22-2017, 11:00 AM
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No Cobalt engine was sold as a Flex Fuel engine - therefore, you cannot safely run E85 in your engine.

It won't ruin anything (anything since the mid-80s is equipped to handle any amount of ethanol in fuel), but the engine will absolutely not run properly. While E85 is technically 105 octane, you also need to use about twice the amount as "normal" gasoline, as the amount of energy contained in each molecule is much less.

So, your engine is likely going to retard timing to an extreme degree to try and prevent engine knock as much as possible, which will make it run much less than efficient - you may notice a drop in available power, as well as far lower fuel efficiency.

In the future - do not put E85 in the car, unless you're specifically tuned for it.

Out of curiosity, why did you want to try E85 in the vehicle? It may be cheaper per gallon, but due to what I mentioned above (less amount of energy per gallon than gas), you'd experience a decent drop in fuel economy, even if you were tuned for it.

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post #4 of 4 (permalink) Old 10-22-2017, 02:08 PM
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I wish it was easy to avoid E-10.
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