Ethanol Gas Causes Engines to Run Hotter - Leading Consumer Magazine

[Joseph P. Indusi]

I have long suspected and heard that gasoline with ethanol (currently 10%) where I live will cause engines to run hotter. There may be good technical articles out there that can confirm this through experimentation but I have never run across any. However, latest leading consumer magazine states the EPA bans use of E15 in mowers and other power equipment due to higher operating temperatures that cause engine component damage. Article also claims that even with 10% ethanol there may be higher operating temperatures. They also claim that ethanol can cause other corrosion related problems. They recommend using an additive such as Sta-Bil to protect against ethanol settling out and attracting moisture.

Having been a subscriber to this magazine for many years I find that they are generally on the side of conservation and environmental protection so the fact they published this article makes me think it is correct; in fact they claim that a Department of Energy study is the basis for the hotter operating temperature with E15.

This kind of confirms my memory, bad as it is, about how rarely cars in good condition overheated back in the day. Given that our old cars may not be as good as when new even with our best restoration efforts, it seem that the gasoline we are forced to use is contributing to the potential for overheating.

Joe, BCA 33493

[rons49]

I read the same article, Consumer Reports issued it. My take was if it is bad for small engines why is not detrimental to larger ones?

[Joseph P. Indusi]

rons49:

I agree and that was my point in this posting.

Joe

[carbking]

If we took all the money that has been spent on service required by ethanol, and modification to prevent problems from ethanol; we could probably buy Saudi Arabia!

Jon.

[MCHinson]

Guys, While I am not an ethanol fan myself. These types of discussions are difficult to keep focused on the old car hobby, and often result in posts being deleted. Can we please try to keep the discussion civil and simply focus on the effects on ethanol on the old car hobby and less on the politics? Thanks.

[Guest Magoo]

I'm interested in the reasoning or evidence behind the claim that ethanol fuels would make an engine run hotter. This seems counterintuitive, since ethanol is lower in caloric content and is also more knock resistant.

[rocketraider]

I think it's because, as an oxygenate, it causes leaner fuel mixtures which tend to run hotter. Fuel induction systems have to be richened up to compensate for that, with consequent worse fuel mileage.

[Rusty_OToole]

I'm interested in the reasoning or evidence behind the claim that ethanol fuels would make an engine run hotter. This seems counterintuitive, since ethanol is lower in caloric content and is also more knock resistant.

Short answer: alcohol leans out the mixture and makes engines run hotter. To all you chemists out there, I know this is not 100% accurate. Feel free to write a 10000 word essay explaining in detail why I am an idiot.

[padgett]

No, can say in a sentance: Ethanol may run hotter in an engine not designed for it. Ethanol naturally burns slower than gasoline and is detonation resistant. It also takes a richer mixture since it does not produce as much energy. Now the games producers play to maintain the same PON (pump octane number) can include adding ethanol to lower octane gas to maintain the same flame propagation rate.

I run my Judge a bit rich (71 instead of 70 jets) to compensate but that is mainly because 93 is about 97 old style and the warmed-over RA 400 runs better that way. It also likes a bit more aggressive advance and I drive it so little that the dropped MPG is trivial. If there is ever a problem, I have some 6X heads I can drop on.

Modern cars particularly flex-fuel (my tow car) have the expanded fuel and advance maps to compensate for nearly any amount of alky. Lawnmowers often still have carburettors that don't and are usually overloaded anyway.

All that said since I tend to keep cars for decades, I like to run them about 10 % cooler than the factory spec and am aggressive with cooling fans to limit excursions. I agree it is important to keep engines cool just am not concerned about Ethanol (other than replacing anything old with ethanol-proof fuel lines).

Edited March 31, 2013 by padgett (see edit history)

[NTX5467]

It has always seemed to me that there were TOO many hoops for retailers to jump thorough for them to have the priviledge of selling the allegedly "better choice" E15 fuel to consumers for them to really embrace it . . . unless they had to. I've seen that most station's fuel pumps are already approved to handle E15, but how are the sellers going to enforce the "4 gallon rule" of E15 purchases? What happens if a consumer has their 2 gallon fuel container, to get some lawn mower gas, only E15 is available, yet has to get the yard mowed, but doesn't want to travel in search of non-E15 fuels? Does this consumer "purchase" 4 gallons and then hope to hit the emergency pump cut-off as the container over-flows?

By observation, there's been far too much politics invovled in the whole E15 deal and those politics have tended to "flavor" the "scientific data" generated by funded-research.

The small engine carburetors are generally "fixed-jet" in nature and have NO each way to recalibrate them for anything like E15 fuels, which require "richer" calibrations than for E10 fuels. The optimum A/F ratio for E10 is 14.2 as E0 is 14.8, but for E15 it's about 13.2 (which is sqarely in the "power enrichment" section of many carburetors where normal cruise A/F was 14.8). Having many of them now "fixed-speed" in nature makes it easier for them to meet CARB emission levels, I suspect, with their "basic" style of carburetor.

On the grander scale . . . I found a 2008 GM TSB which plainly states that ONLY "FlexFuel-rated" vehicles should use gasoline with anything greater than 10% ethanol in it--period. Particular model years and models are listed which could be "FlexFuel" in nature. The TSB also states that "conversion" to FlexFuel status is more than just a computer recalibration issue. By this time, though, all of the earlier vehicles are far outside of any warranty coverage, so repairs would be squarely on the consumer . . . especially as (I understand) part of the E15 implementation legislation releases the government for any liability involved in using E15 in any vehicle that was not designed to use it, although such vehicles would fall under the "Model year 2001 and newer" government approvals. So, respectfully, do we seek to use E15 as "The Governmenrt" says we should or do we NOT use it as the vehicle manufacturer details which vehicles it did not design to use E15?

From the research I've done on the subject, it appears that isobutanol is a far better oxygenate, although it will take 16% to match E10s oxygenate level and performance. PLUS it's been on the EPA's list of acceptable gasoline additives since 2008? It is NON-hygroscopic, so it can be transported by pipeline, rather than "point of transportation splash-blended", with the IB16 fuel needing less gasoline base stock than E15. Briggs-Stratton has approved of it, as had an outboard motor manufacturer. Existing ethanol plants can be easily converted to produce it, too! YET all federal legislation is aimed at ethanol use only, it seems.

I suspect that the main issues with ethanol use are more related to the drying action which it has on the rubber components of the fuel system. As the "oils in the rubber" are depleted, it can crack and allow fuel to seep through it, which further deteriorates the item. I've recently heard of the inside-out action on fuel lines having the scenario that, as the ethanol dries out the inner layers of fuel lines, the fuel further seeps into the core reinforcement layer of the hose, then proceeds to the outer layers of the hose, which then flake off, leaving the inner reinforcement cord exposed . . . and fuel leaks can begin.

The "buna"-compound rubber used in fuel pump diaphrams is resistant to ethanol . . . until it the over-time evaporation of the ethanol-blend fuel leaves the fuel pump diaphram dry, which will then become brittle. Hence, when the engine is restarted, the fuel pump diaphram can soon fail, leaking fuel externally and possibly into the crankcase. Not to forget about similar things happening to the accelerator pump diaphrams on many Holley carburetors, which are located on the bottom of the carb's float bowl! Isobutanol has NONE of those issues.

I haven't seen the particular CR article, but I wonder just what sparked their interest in this issue? In an earlier article, a few years ago, they noted how much using E85 fuel in a FlexFuel vehicle would decrease fuel economy, positioned against the cost of E85, I believe they concluded it was not a "cost-saver" for the consumer?

Regards,

NTX5467

[padgett]

Folks can we leave the politics (which we have no control over) out. The real answer is diesel but that has been a no-no since caddys played armadillo on the interstates in the '80s. Brazil has uses E100 for years and engines there are designed for it just as oil well pump engines are designed to run on natural gas (byproduct). In the past local issues have made engines that could run on almost anything. I recall the original HUMMMV could run on peanut oil and that is just internal combustion engines, external combustions engines can and have used wood logs.

Additives and mixtures have existed for as long as there have been cars, my XK-150s (long gone) owner's manual included instructions on removal of the heads for decarbonization. Plugs rarely foul now. When was the last time someone had trouble with water in the gas or gas line icing (both prevented by ethanol the same as the winter additives that used to sell in gas stations.

As mentioned is that the real issue with E85 is that to be competitive, it needs to sell for about 3/4 the price of gasoline to have the same cost per mile.

The only real political element is that producing Ethanol from corn is really very inefficient compared to things like sugar beets and sweet sorgham. However we have a lot of corn. And on the plus side, unlike many countries, the US does not tax gas very heavily. Of course that coud change with the stroke of a pen.

So lets stick to the effects of ethanol and how to compensate for them. Only real change I've made other than to use slightly richer jets is to use only new carb kits and fuel lines. That is one place that NOS should stay on the shelf.

ps is anyone else left who remebers how to drill out a jet ? Or is everyone a parts swapper now ?

Edited March 31, 2013 by padgett (see edit history)

[Mark Huston]

I have been an owner, and driver, of 1929 Studebakers since the early 70s. In all of those years of driving I have never had problems with the engines running hot and vapor locking until recently. The cars are in good mechanical condition, and well maintained. The only variable that I have no control over is the fuel mixture sold at the pumps here in California. Everything that I have read points to Ethanol gas as the problem for both the running hot and vapor locking.

My question is what am I supposed to do? Stop driving my car? Only drive when the temperature is cooler – which means leaving early in the morning and turning around and going home as soon as I arrive. The afternoons can get into the 90-100s here most of the year.

I have heard of adding diesel fuel, 2-cyle oil, transmission fluid, airplane gas, and other home brews to the gas tank. Does anyone know if these really compensates for the Ethanol in the gas? Will unauthorized additives in the gas tank help with both the vapor locking and the engine running hotter? What additive is best? What is the ratio? How much per gallon of gas do you add to the tank?

I want to keep driving my car year round, not just in the winter when it is cooler.

[Guest Bill Miller]

Regarding Mark Huston's question above, I've been adding 2-cycle engine oil to my older cars for a long time now and this has cured the vapor lock problems I've experienced. I use a couple of ounces per half-tank fill-up and I also add Stabil preservative. I keep the tanks on my cars full. Some people use Marvel Mystery Oil instead of 2-cycle oil which is fine but more expensive. Diesel fuel will work also but it contains sulfur which will corrode any yellow metals (brass, copper, bronze) with which it comes in contact so it is unsuitable for many prewar cars. The idea is to reduce modern fuel's volatility by adding oil to reduce the tendency of the fuel to vaporize in the lines at hot points. Works for me. Airplane fuel is available for purchase at smaller airports and is ethanol-free but you will be violating federal law if you use it in a highway vehicle. However, it's likely nothing will work in older vehicles if we eventually get to E-85 as the only fuel alternative.

Bill

[joe_padavano]

I don't subscribe to Consumer Reports, so I haven't read the article. As others have noted above, ethanol by itself does NOT cause overheating. The lean mixture is what causes overheating, whether caused by ethanol or not. The reason why this is not a problem for automobiles is that something like 95% of all cars on the road today use either fuel injection or feedback carburetors that adjust the mixture to avoid being too lean. Small engines (and older cars) that do not have an O2 sensor and active mixture control are the ones at risk. I'm guessing that this is much more of a problem with air cooled small engines than with a liquid cooled automotive engine.

Personally, anything that uses less imported oil is good as far as I'm concerned, but what I'm upset about is that the original reason for using "oxygenated fuels" was to reduce hydrocarbons emitted by carburated engines in the winter when the choke was on. The advent of the O2 sensor and feedback mixture control negates this effect since the computer simply richens the mixture to compensate (lowering fuel mileage in the process).

[edinmass]

OK gentlemen, I have not commented on this topic for the past ten years as the debate can be quite intense. Here is a chart done by a Shell fuel engineer from the 50's and 60's. A grad of Cal Tech, he left Shell for NASA and engine and fuel design for Gemini and Apollo. He would never discuss fuel at shows because of all the arguments from people with no background in chemistry or engineering. Stoichiometry is the science behind air / fuel ratio. This chart was done at the Pierce Arrow national meet 8 years ago while having drinks overlooking the show field. The conversation lasted a few hours. Read and enjoy. Comments welcome. I'll also comment later on what we find using chassis dyne's and real life road testing. ENJOY! Ed :cool:

Download the photo and then you can zoom in.

Edited March 31, 2013 by edinmass
more info (see edit history)

[edinmass]

Just a short not on the above chart. It shows 1930's fuel and compares it to all modern fuel blends and E85. Take your time to read it and look over it's findings. I find most of the detailed comments above to be correct and insightful. The end result in almost all cars with carburetors and no feed back for mixture control is more fuel and more timing. Ed

[NTX5467]

Thanks for that information, Ed!! Quite interesting, especially the flow rate differential for E85!

NTX5467

[Guest Magoo]

So it seems we can substantiate numerous reasons to dislike E10 ethanol, but elevated engine temperature is not one of them.

Actually, here is one of the cherished half-truths of automotive lore: that "lean mixtures make engines run hot."

Under the broadest range of operating conditions and loads, the opposite is true. Engines actually run cooler on leaner mixtures. Which only stands to reason: where less fuel is consumed in a finite volume of air, less heat is produced.

There are two secondary mechanisms by which lean mixtures can elevate operating temperature, especially at/near maximum load: 1) By inducing knock 2) reduced evaporative charge cooling.

However, ethanol actually *increases* evaporative charge cooling and *reduces* knock. In this case we lack an effective way to elevate engine temperature.

Summing up, we also note that stoichiometry for ordinary gasoline blends is around 14.69:1; for E10 ethanol 14.13:1. Makes you wonder what all the uproar is about. Especially when you consider that in most areas of the country, "normal" gasoline contains at least several percent alcohol to serve as oxygenate, antiknock agent, and deicer. Meanwhile, E10 contains maximum 10 percent ethanol. Panic seems unwarranted in this instance.

[R W Burgess]

.......... Article also claims that even with 10% ethanol there may be higher operating temperatures. They also claim that ethanol can cause other corrosion related problems. They recommend using an additive such as Sta-Bil to protect against ethanol settling out and attracting moisture.

Makes you wonder what all the uproar is about. Especially when you consider that in most areas of the country, "normal" gasoline contains at least several percent alcohol to serve as oxygenate, antiknock agent, and deicer. Meanwhile, E10 contains maximum 10 percent ethanol. Panic seems unwarranted in this instance.<!-- google_ad_section_end -->

Magoo, the original poster seemed concerned about the overheating problems, but from his own statements concerning Corrosion and the use of Sta-Bil, I'd say the uproar is over the damaging effects on small engines and older model engine components.

[R W Burgess]

I forgot to mention that I now have 2 small engines of my own with fouled carburators. Yes, I should have added a preservative, but why should I be required to have to add treatments to fuels produced by others?

Wayne

[Dave@Moon]

Makes you wonder what all the uproar is about..

"We need the eggs."--Woody Allen, 1977.

There can be no other explanation, if there were I would have run into it 30+ years ago when e10 was already the only gasoline I could buy in the state I was living in (repeated here for the 93rd time, but still no one will notice or care).

[john2dameron]

I think all the gas available in this area has ethanol in it and every year I take lawn mowers to the shop over and over. What is the answer? Stabil does not seem to be the answer. Is there an solution to the problem?

[MCHinson]

John,

I drain the tanks and allow the engines to run until the carburetor runs out of fuel and the engine stops before storing for any length of time. I have not experienced any problems with my small engine equipment. It is not as easy with an antique car.

[Dave@Moon]

John,

I drain the tanks and allow the engines to run until the carburetor runs out of fuel and the engine stops before storing for any length of time. I have not experienced any problems with my small engine equipment. It is not as easy with an antique car.

This is exactly what I do as well. You have to store (fresh) ethanol gas for months before it can absorb enough atmospheric water to do any damage. I've posted on other threads how much water it takes to make this stuff into a problem. Suffice as to say it takes a lot, and it takes a degree of neglect to let things get out of hand enough to cause real damage.

(Of course "neglect" is relative, and is intended here to reflect care of the fuel and not the engine. Care that was perfectly fine with "pure gasoline" just doesn't cut it any more.)

As for antique cars, I'm fairly lucky in that mine have relatively modern (1970s), reasonably well sealed systems. Keeping them full during the winter eliminates air from the tank, and therefore almost all water from the fuel. I then run the car in place (safely) at least monthly to have keep the seals lubricated (a habit I got into trying to keep fluid in my old Dynaflow over the winter). Cars with well-vented systems should be stored the same way to eliminate as much air exposure as possible, and refilled with fresh fuel as necessary. Either way any gas so stored should be used up as soon as possible in the Spring regardless of any stabilizer used. Fuel somewhat exposed to the air in well-vented systems can be siphoned in whole or in part and used (diluted with fresh fuel) in newer vehicles to help with this.

No doubt, it's a pain. But years from now when even e10 gas is tough to find we'll miss these days as much as we miss the days of ubiquitous Sunoco 260. Remember, even whale oil used to be relatively cheap and plentiful.

[packick]

We just purchased a new 2013 car. With respect to many gas stations moving to 15% ethanol, our owner's manual specifically states that if any engine damage is the result of using fuel with more than 10% ethanol, the warranty is no longer valid. I just thought I'd throw that into the mix (no pun intended).

[carbking]

Two issues which cause small engines to run hotter are: (1) most small engines are air-cooled. The lower energy content of the ethanol causes the engine to work harder to perform the same task; and (2) modern fuels evaporate much more readily than previously AND LEAVE A RESIDUE WHICH OVER TIME PLUGS PASSAGES, JETS, ETC. IN A CARBURETOR. The partially plugged jets don't flow sufficient fuel and the engine runs excessively lean.

An example of the above:

I personally own a collectable John Deere lawn and garden tractor which is for sale. It hadn't run for some time, and last year I got it ready for sale in April. It would start on starting fluid, but not on fresh fuel. I rebuilt the carburetor, and the engine ran as it should. It did not sell in April, and we had another garage sale in July. Went to get out the Deere and it wouldn't start. Drained the tank, filled with fresh fuel. Would start on starting fluid, not on fuel. Rebuilt the carburetor, and it ran great. Did not sell. The exact same thing happened in October!

I have personally experimented with stabil, seafoam, and a couple of other products available locally. The only change I have personally noticed was the transfer of funds from my account to the account of the parts houses!

I now find the only way to prevent the problem of these small engine carburetors clogging with the fuel available locally (yes Virginia, we have deathanol in our fuel) is to start each one once a week. This also has the benefit of keeping the batterys charged.

The other thing I find about this fuel is that if you leave the fuel for more than maybe 60 days it plain will not burn unless you start the engine on fresh fuel and get it hot; then if 60 day fuel is introduced to the tank you can burn it. Of course you need to burn most of it out and refill the tank with fresh or the engine will not start the next time.

I think my answer may lie in the fact I have several collectable John Deere ELECTRIC riding mowers. Hopefully, I will have time this summer to get a couple of these running, and forget about the fuel!

My experiences, others may differ.

Jon.

[Guest heftylefty]

Folks can we leave the politics (which we have no control over) out. The real answer is diesel but that has been a no-no since caddys played armadillo on the interstates in the '80s. Brazil has uses E100 for years and engines there are designed for it just as oil well pump engines are designed to run on natural gas (byproduct). In the past local issues have made engines that could run on almost anything. I recall the original HUMMMV could run on peanut oil and that is just internal combustion engines, external combustions engines can and have used wood logs.

Additives and mixtures have existed for as long as there have been cars, my XK-150s (long gone) owner's manual included instructions on removal of the heads for decarbonization. Plugs rarely foul now. When was the last time someone had trouble with water in the gas or gas line icing (both prevented by ethanol the same as the winter additives that used to sell in gas stations.

As mentioned is that the real issue with E85 is that to be competitive, it needs to sell for about 3/4 the price of gasoline to have the same cost per mile.

The only real political element is that producing Ethanol from corn is really very inefficient compared to things like sugar beets and sweet sorgham. However we have a lot of corn. And on the plus side, unlike many countries, the US does not tax gas very heavily. Of course that could change with the stroke of a pen.

So lets stick to the effects of ethanol and how to compensate for them. Only real change I've made other than to use slightly richer jets is to use only new carb kits and fuel lines. That is one place that NOS should stay on the shelf.

ps is anyone else left who remembers how to drill out a jet ? Or is everyone a parts swapper now ?

With small engines there are two issues, fuel mixture and materials compatibility.

I do not have experience with the current consumer small engines so if the carb jets are not removable drilling seems like a bad idea as there is no going smaller. Perhaps replacements are available with removable jets.

The plastics I remember seeing on some of the Briggs and Tecumseh fuel systems I saw on the mowers I worked on were clearly not alcoholproof. They were turning to mush or hardening and cracking. These inferior materials are used because, in my estimation, these machines have to retail for a very low price and they would have to pay more for alcoholproof ones. The retail consumer answer to this problem I see at the retailers I frequent is they are selling special alcohol-free motor fuel in small cans for the equivalent of $10 to $20 a gallon. This means they can not only continue selling the "Cheap" lawn mower but then the special lawn mower fuel for the next several years. That's why Coleman refused to sell multi fuel lanterns to the public for a long time.

Consumers aren't very smart or else they would buy a good lawn mower with an iron cylinder liner and maintain it for many years instead of buying the cheapies and throwing them out. So this business model makes lemons out of lemonade for the retailers.

[Guest heftylefty]

"We need the eggs."--Woody Allen, 1977.

There can be no other explanation, if there were I would have run into it 30+ years ago when e10 was already the only gasoline I could buy in the state I was living in (repeated here for the 93rd time, but still no one will notice or care).

For cars, the long term fact is that the car has to be made (that means modified) to fit the fuel available. The small engine juice is available in barrels but the price will be a killer, it will probably work in a flathead car engine. There's avgas and it's technically illegal but the fact is no one cares. Neither is a viable solution on the road.

But then again I remember reading in "Pur Sang" the Bugatti owner's club magazine about a guy that ran a Bugatti on methanol a thousand miles on a tour. This was in the eighties. He had a guy follow him with barrels of the stuff in a truck. If memory serves he ran it the whole time on Castrol R engine oil-that, for the uninitiated is castor oil.