Piston Slap: The Corrosive Effects of Ethanol Laced Gasoline?

Sajeev Mehta
by Sajeev Mehta

Misha writes:

Hi Sajeev!

I’m a long time lurker, first time asker. I was curious about the effects of E85/E90 ethanol laced gasoline. I have read a bunch about how older cars are susceptible to corrosion damage to various parts of the fuel line.

I was curious to know if this, or any other ethanol related problem, is still applicable in modern cars? Thanks a lot!

Sajeev answers:

Let’s try to avoid the Ethanol Sucks/Support Our Farmers debate, hmm-kay? Long time TTAC readers already know where “we” stand on the issue.

Cars older than 2001 cannot run gasoline with more than 10% ethanol in the mix. Most newer cars cannot run E85/E90 because they aren’t tuned/programmed for it. Older cars (and small gas engines like lawn mowers) with rubber fuel lines are totally screwed, and perhaps also there’s a concern with corrosion of metal components. But ethanol is only corrosive in some applications: per Wikipedia:

“High alcohol fuel blends are reputed to cause corrosion of aluminum fuel system components. However, studies indicate that the addition of water to the high alcohol fuel blends helps prevent corrosion. This is shown in SAE paper 2005-01-3708 Appendix 1.2 where gasoline/alcohol blends of E50, nP50,IP50 nB50, IB50 were tested on steel, copper, nickel, zinc, tin and three types of aluminum. The tests showed that when the water content was increased from 2000ppm to 1%, corrosion was no longer evident except some materials showed discolouration.”

I spoke (off the record? Ish?) with a Ford engineer friend of mine…just to make this posting a little more kosher.

“It’s only calibrated to do so if it’s advertised. I know at Ford we slap E85/E90 on the capless filler if it can take it. So like on newer cars like the 2.0L Focus, yes. But legacy powertrains like your Ranger, no. ( except the 3.0L Vulcan, GOTCHA! – SM) It’s all in the calibration and the capabilities of the ignition system.”

What’s the key takeaway here? RTFM…son!

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Sajeev Mehta
Sajeev Mehta

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  • 285exp 285exp on Jun 17, 2013

    Scoutdude, You have a link to those studies showing those 10% reductions?

  • Gearhead77 Gearhead77 on Jun 18, 2013

    My lawn equipment dealer said to run premium (91 or 93) in power equipment. They said that it generally has less ethanol in it and they don't see the breakdown in fuel system components as often when people use premium. I run premium and an ethanol "protector" sold by Lucas in my power equipment. My mower is only two years old, but the weed-eater is about 6, no problems with starting, running and no brittle fuel line. It is a Shindaiwa, which is not your typical $70 big box special. As far as aviation goes, I'm a big proponent of diesel being the fuel of choice in the future for light aircraft. Diesel and jet fuel are fairly close and are interchangable. Diesel is not without its faults, but it has to be better than pumping unrestricted 100LL byproducts into the air. Problem is, diesel engines are available to general aviation. The cost can be around $50,000 though, which on older single engine airplanes like a 172 and Piper Cherokee, can be what the entire airframe is worth. Of course, a new 100LL engine is around 25k for these airplanes too, which depending on use, could be every 3-10 years. I know Cessna has a turbodiesel 182 available. At $515,000 new...

  • TCowner We've had a 64.5 Mustang in the family for the past 40 years. It is all original, Rangoon Red coupe with 289 (one of the first instead of the 260), Rally Pac, 4-speed, factory air, every option. Always gets smiles and thumbs ups.
  • ToolGuy This might be a good option for my spouse when it becomes available -- thought about reserving one but the $500 deposit is a little too serious. Oh sorry, that was the Volvo EX30, not the Mustang. Is Volvo part of Ford? Is the Mustang an EV? I'm so confused.
  • Mikey My late wife loved Mustangs ..We alway rented one while travelling . GM blood vetoed me purchasing one . 3 years after retirement bought an 08 rag top, followed by a 15 EB Hard top, In 18 i bought a low low mileage 05 GT rag with a stick.. The car had not been properly stored. That led to rodent issues !! Electrical nightmare. Lots of bucks !! The stick wasn't kind to my aging knees.. The 05 went to a long term dedicated Mustang guy. He loves it .. Today my garage tenant is a sweet 19 Camaro RS rag 6yl Auto. I just might take it out of hibernation this weekend. The Mustang will always hold a place in my heart.. Kudos to Ford for keeping it alive . I refuse to refer to the fake one by that storied name .
  • Ajla On the Mach-E, I still don't like it but my understanding is that it helps allow Ford to continue offering a V8 in the Mustang and F-150. Considering Dodge and Ram jumped off a cliff into 6-cylinder land there's probably some credibility to that story.
  • Ajla If I was Ford I would just troll Stellantis at all times.
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