kamachi81

A month or so ago I filled up on ethanol in my C300. Only problem is I have a 4matic and it isn't supposed to run on ethanol. I guess the salesman was confused when he told me the car would run on ethanol because when i took it to the MB dealership they said my 4matic doesn't take ethanol. They ran some tests on it and found it wasn't causing any problems and they recommended just driving it out and filling back up with premium. Over the next few days I didn't notice anything different (other than the check engine light being on). No spark knocking. Nothing out of the ordinary. To top it all off the mileage seemed to be the same if not better than the premium I usually get. I haven't put any ethanol in it since then but i was wondering if anyone else has done the same? Obviously I have discovered that putting ethanol in my car doesn't screw it up so my next question would be do you think that the prolonged use of ethanol in the car would cause any harm? My father is an old school mechanic and he says you can put anything in a car and if it doesn't spark-knock then you can use it. Granted he's a ford/chevy guy. What kind of impact would it have on a benz?

Is this one of those deals where they say it doesn't support ethanol because tests didn't meet their benchmarks, expectations, and/or goals?

chilledbenz

The computer systems in cars today are smart enough to adjust themselves when the wrong grade of fuel is put in, such as using 89 octane and the usual outcome is less horsepower and lower gas mileage. In this situation I'm going to side with Mercedes Benz and say that its not a wise idea to be using Ethanol in a car it's not recommended in. They do the tests, they know their engine's better than we do, if they say not to do it then I'm sure they know something we don't. Sure a one time mistake might not result in any noticeable problems, but over a prolonged use something must happen that MB doesn't like or they wouldn't have advised against it.

By the way, I'd be willing to bet that if you continued to use it in your car and something did happen your warranty would be voided and you would have to foot the bill.

kamachi81

You are right on about the warranty. I have put nothing in it but premium with the exception of that blunder and will continue to do so but just curious that when in 5 years from now and gas is $345 a gallon, I may have to draw the line and say time to start using lower grade.

Untertürkheim

If you look at the math, using lower grade fuel becomes more expensive as the fuel prices rise, since the fuel economy decrease is constant while the price differential between regular and premium is always getting smaller.

RLE

Please be specific. Do you mean E85 or E10? Is your car a flex-fuel vehicle or not. My C300 Lux automatic is but I don't recall if the 4-matic is but it uses the same engine.

The flex fuel engines use a lot of different parts (including the engine computer) and the fuel tanks are made of a different material to resist being eaten up by the ethanol.

micropower99

E85. I don't think I have ever seen or heard of E10 at gas stations. (Never seen any ethanol fill ups in general in Canada yet anyways) But yea the 4Matic's are not allowed to use ethanol as a source of fuel. It was stated many times in the brochures.

jrct9454

Precisely.

I surely wouldn't take the long-term risk on any car that MB hasn't cleared for E85 use.

And the math on the premium vs regular question [which seems to come up every 5 minutes these days] is simply not compelling. The difference around here is less than 5%; your fuel use on regular would likely be about 2-2.5% higher, though that's hard to measure [a tenth of a mile per gallon?] - anyway, it just makes no sense at all to take any risks when the numbers involved are so puny. If you spent $1800 a year on fuel, the difference would somewhere in the neighborhood of $90.

If that kind of money is that important to you, without trying to offend, you're probably driving the wrong car.

Parenthetically, I just saw a post on one of the Edmunds boards from a VW owner who bought the 2.0 Turbo [Jetta Wolfsburg] thinking he could use regular in it, and is up in arms when he discovered it required premium because he wanted to "save money on gas, which is why he got the car in the first place" - someone tried to point out, as gently as possible, that the 2.5 5 cyl in the Jetta has approx the same mpg rating, and runs on regular, and is cheaper to buy, and never mind the gazillion other cars out there with better fuel consumption that run on regular. In my personal experience, which is pretty extensive, I don't think I've ever heard of a modern turbo-charged gasoline engine that didn't require at least 91 Octane [US measurement] - but the salesman allegedly told him otherwise [now there's a shock....].

jrct9454

By the way, Kamachi, did the CEL clear itself after refilling with gasoline, or did someone have to intervene?

ShoremNJ

I don't have to worry about E85 as NJ has no vendors....lol

RLE

E10 is just another term for 10% ethanol which can be used in all MBs for the last perhaps twenty years or so. Luckily here in Western Washington the only gas with it at this point is ARCO which I never use. Shell and Exxon are at the moment ethanol free but I've been hearing lately that E10 is going to be the only thing available later in this year.

When you use the E10 version, fuel economy drops 10% immediately. Personal experience.

When switching a flex fuel vehicle to E85, the tank should be at 1/4 or less but not into reserve. The oxygen sensors then sense a lean mixture and fuel flow is increased to correct the mixture.

jrct9454

In another of those govt interventions that always invokes the Law of Unintended Consequences, stations across the Columbia from us in Oregon are REQUIRED to sell all gasoline with 10% ethanol.

Here in Clark County [Vancouver WA], we too are mostly still getting gasoline without the alcohol, so there have been multiple news stories of drivers from Portland coming here [or stopping on their way home if they work here] to fill up with "real gasoline".

Because Oregon requires a "trained professional" [insert laughter here] to pump gasoline into your car, I do everything I can to avoid buying any fuel in Oregon, even though it's a few pennies cheaper than Washington. When we head south to visit friends and relatives in California, I top off the tank so I can get through Oregon entirely without having one of these station guys/gals getting anywhere near my car - thus, I haven't experienced "E10" much. Elsewhere in the West, it's a mixed bag - some brands are "ethanoled", some not.

I too have heard that our WA-refined fuel may soon contain the corn-mash....we'll see.

ColoradoDriver

The last hold-out stations in Colorado have now gone E10. They were forced to do so by law.

Will617

Sorry about your bad luck but I would stay away from it.
My wife drives a Mini Cooper,S. Just a few weeks ago it wouldn't start. Battery had plenty of spark so I had it towed to the Dealer. Service told me it was the fuel pump and he has seen a few of them ( CooperS ) with the same problem. They are blaming it on Ethanol.

RLE

Has this been mandated by the EPA or the State? In Washington State (about fifteen years ago) E10 became the rule because certain areas (defined by zipcode) did not meet EPA air quality standards in the winter but after about four years our air was clean enough that the EPA order was cancelled and we have not seen E10 since except in the stations that want the profit that E10 brings to them. ARCO is one of those companies and also no-name gas sold by some of the supermarkets such as Albertson's. My card-op station buys their gas and diesel from Exxon and I verify that from time to time.

ColoradoDriver

I believe Congress is pressing this. California's air quality board even tried to avoid it, but was turned down!

luisfdezzz_

Today I filled up 3/4 of my tank with E-85. Hours later my check engine light turned on. I have a Mercedes c300 4matic 09. The manual says fill up with premium and e85 only I don't know what the problem is

Acapulco Bill

Despite what the OP claims, it is impossible to get the same MPG from E85 Flex Fuel as 89/91 Octane gasoline. Chemically, there is 20% less energy per gallon in E85 vs. gasoline, this due to the number of electron bonds that will be broken and oxidized in the combustion process. To see if E85 is more economical, multiply the price per gallon (or liter) by 1.25 and compare it to the gasoline price. Remember that 89 and 91 octane have the same energy content, the difference is the statistical number of shorter or longer carbon chains - the higher the octane rating, the closer it's antiknock characteristics are to pure 8-carbon-chain Octane.

Not all C300's are Flex Fuel capable, check the information inside the fuel filler lid door. For sure the C350 and the C300 with the 3.5L engine cannot use E85. Also, E85 causes degraded performance, as ethanol provides less power vs. gasoline with each ignition within the cylinder.

w204_Generic

Adi-Benz

As said above check fuel fill cap. If it doesnt say e85 dont do it.