Does gasoline really burn off of oil?

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On one of the videos of cold starting an engine it was shown how, when cold, unburned gas can get past the piston rings and mix with the oil. The video also showed two oil samples, one clean and one mixed with gas from cold engine starts with short runs, engine never fully warmed up.
Even with a long engine run where the engine gets up to operation temperature for +15 minutes does the mixed gas really ever "burn" out? Obviously the gas doesn't catch on fire and burn but then how else is it removed from the oil at temps of about 200F? I can see how water will boil off at these temps but what gets rid of the gas? Does it just boil off like water? Will the nasty ethanol be removed as well?
 

Shel_B

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On one of the videos of cold starting an engine it was shown how, when cold, unburned gas can get past the piston rings and mix with the oil. The video also showed two oil samples, one clean and one mixed with gas from cold engine starts with short runs, engine never fully warmed up.

It would be nice if you'd provide a link to this video, then we can all see what you're describing.
 
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Folks call it 'burn off' because it's heat-accelerated evaporation. Yes, gas will evaporate out of the oil, and the longer it's churned and heated, the quicker it will happen. I'm not sure about the evaporative properties of Ethanol, but if you're ever witnessed how quickly a puddle of Isopropyl can disappear, it'll give you some idea.
 

BrianApp

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Folks call it 'burn off' because it's heat-accelerated evaporation. Yes, gas will evaporate out of the oil, and the longer it's churned and heated, the quicker it will happen. I'm not sure about the evaporative properties of Ethanol, but if you're ever witnessed how quickly a puddle of Isopropyl can disappear, it'll give you some idea.

I was thinking ethanol was the gummy junk that separates out from gas, after 30 days or so, and is left to gum up injectors and other engine parts. If it acts more like grain alcohol I guess it goes away even faster than gas. Why is it that I keep hearing that ethanol can gum up an engine if stored over thirty days but ethanol free gas is preferred and doesn't have these problems?
 
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I was thinking ethanol was the gummy junk that separates out from gas, after 30 days or so, and is left to gum up injectors and other engine parts. If it acts more like grain alcohol I guess it goes away even faster than gas. Why is it that I keep hearing that ethanol can gum up an engine if stored over thirty days but ethanol free gas is preferred and doesn't have these problems?
Fresh ethanol gas that isn't left sitting doesn't really have an effect that I've witnessed. It's with the passing of time that things turn ugly.

 
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I started to read that linked article above, but the second sentence was GROSSLY INCORRECT so I figured the rest of the article is just as worthless.
 
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I started to read that linked article above, but the second sentence was GROSSLY INCORRECT so I figured the rest of the article is just as worthless.
I just put it in to explain the process better than I could find the words for:

Phase separation is when ethanol in the fuel absorbs too much water, and separates from gasoline by dropping to the bottom of the tank since the ethanol and water mixture that results from phase separation is heavier than gasoline. Water-ethanol solutions can damage fuel systems and engines
 

BrianApp

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My next question about ethanol is why is the ethanol free gas typically %30 more expensive than the standard %10 ethanol, $4 vs $3 a gallon? I get ethanol may be cheaper but even if it was free Adding %10 of it should only lower the price %10. I assume ethanol cost something and that the extra step of transporting it to and mixing it at the refinery isn't free either. Does the government PAY the gas companies to put the ethanol in there and give it to them for free?
 
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Ethanol will oxidize to acetaldehyde and this will oxidize to acetic acid (why wine goes dour). The aldehyde and the acid can cause all types of organic reactions to occur and cause "gum" to form.
 
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My next question about ethanol is why is the ethanol free gas typically %30 more expensive than the standard %10 ethanol, $4 vs $3 a gallon? I get ethanol may be cheaper but even if it was free Adding %10 of it should only lower the price %10. I assume ethanol cost something and that the extra step of transporting it to and mixing it at the refinery isn't free either. Does the government PAY the gas companies to put the ethanol in there and give it to them for free?
premium 91-93 octane doesnt cost .60 to $1 more to produce vs 87octane either...

Fuel price differences are somewhat regional.. as is the ethanol free availability.
NE Ohio its only available as rec fuel or marina gas at 90 octane. 4.19+~~/gal

if you want to be mind blown check out these gas prices at a local sheetz station.
(blue 88octane is upto 15% ethanol)
IMG_20200611_174920.jpg


Also while some of the gas will evaporate off.. the oil is changed it wont ever go back to exactly what it was before the fuel dilution.
 
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when and where is this? I would love gas prices like that, for 8 months in Laramie, WY during COVID we had $0.79-0.99 per gallon, which was awesome as I traveled a lot more because of it.
Its not current prices..

my point was the e85 ethanol and the 87 octane both cost significantly more than the 88 which is created by mixing those 2 together.
 

SammyChevelleTypeS3

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premium 91-93 octane doesnt cost .60 to $1 more to produce vs 87octane either...

Fuel price differences are somewhat regional.. as is the ethanol free availability.
NE Ohio its only available as rec fuel or marina gas at 90 octane. 4.19+~~/gal

if you want to be mind blown check out these gas prices at a local sheetz station.
(blue 88octane is upto 15% ethanol)
View attachment 81078

Also while some of the gas will evaporate off.. the oil is changed it wont ever go back to exactly what it was before the fuel dilution.
Why is there an unleaded 88 right next to a regular 87? Is one of them pure or? All we ever had down south is the three on the right and its all 50 to 60 cents a gallon over those prices these days.
 
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Here about 80 miles west of Omaha regular 10% ethanol is 299.9 and 0% ethanol is 30cents more. I really don't know the premium price, as I never use it. My '17 Nissan and my '98 Mustang 3.8l use the 10% stuff and my 65 Mustang and all my OPE use the pure gas stuff. Fo storage of the Mustangs and the OPE I fill the tanks full, and add a strong dose of Stabil to the tank and run it long enough to get it through the fuel systym. Everything works great come spring.
 
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