All I see is a red X.. and this thread is unnecessary anyway.

 

 

lawl it was to own the other thread that got closed

 

run mine on 89...over 160K miles...no problems here....

 

eesjunin do you have your high mileage award?

 

I may be a noob here, but I think this a excellent thread. Especially for other new Mercedes owners that wonder about putting cheaper gas in their cars. I had my valves and head replaced at 34K miles, and after reading this, I wouldn't be surprised if the previous owner only used regular gas and caused the carbon deposits that ultimately blew the valves and the head.

 

Top tier gasolines have cleaning detergents in them regardless of octane rating. The idea that 87 or 89 octane used in your C230 over 34,000 miles caused such a destruction is complete and total BS and furthers the idea some members on here have that regular unleaded is juice of the devil.

I use premium unleaded only in my C230 because that's what it requires. If I decide tomorrow to use regular unleaded from a top tier provider like Chevron from here on out my car will retard timing and I might notice a little loss in performance and a reduction of fuel economy but that's all that will happen.

End of story.

 

One "small" thing to note is that if a MB dealership finds out you didn't use Premium Gasoline in your car, and you take your car to them to repair something that is related to or influenced by the type of gasoline used by your car, then the dealership has a "valid" excuse to refuse to repair that problem under warranty and can void that portion of your MB warranty... even if the gasoline isn't the "real" source of the problem.

From what I've been told, there are tests MB (as well as any other dealership) can do to determine whether you are using Premium Gasoline in your vehicle or not. Therefore, the advice I got was to fill up your tank completely with Premium Gasoline in at least 1 in 4 fillups (but the more frequently the better), so your tank has enough "residue" from the additives in Premium Gasoline to register on MB's tests.


For me personally, I just use Premium Gasoline in my MB's because I like my vehicles operating optimally, and the cost difference between Regular and Premium isn't THAT much of a difference to worry about IMO (usually at most $0.20/gal, which would be a little over $4.00 more per tank in my E350, or a little over $3.00 in my old C240). Besides, recently I've been filling up at Costco, which averages around $0.20/gal LESS than non-Costco stations anyway, so it's like I'm paying "Regular" price for Premium Gasoline.



EDIT: Btw, anyone else notice that your vehicle has a bit more power and "kick" to it when using Costco gasoline? At first I thought it was just my imagination, but I've tested 4 different MB vehicles (1 x C230K Coupe, 1 x C240, 2 x E350) for the past few months in different types of weather/temperature/humidity, at different and same times, and every time I always get the result that all 4 vehicles respond better and accelerate more aggressively with Costco gasoline than Shell/Chevron/76. Weird, eh?

 

I don't buy that MB-tests-for-octane-levels stuff. Too many variables and they'd need to prove it caused the issue. Hogwash.

Hell, I've seen personally that they use 87 octane in their loaner C300 fleets.

 

I just put that cause it looked funny. It wasn't meant to you.

 

Yeah, I know some dealers that do that with their W203's as well, but they ARE the dealership, and those ARE their cars, so I guess it's OK for them to service those cars themselves out of their own pocket while running 87 octane... but they want the customers to pay out of THEIR own pocket when doing the same.

I guess it SORTA makes sense, in a hypocritical and slightly "unfair" way...

 

The fact of the matter is simple, though. Aside from retarding the timing, giving you less power and less mpg, regular isn't going to break anything. In all my dealings with stealerships in the past, I've never had one question the octane of fuel I put in my car. If one ever does, it will certainly be the final time I ever set foot on their lot.. I don't deal well with accusatory dealers.

 

It's completely hypocritical considering those fleet vehicles are going to be sold to some unsuspecting customer, and if they used that logic to deny service in the future.. well.. f*** em!

 

Then I assume you didn't have any problems with your vehicle that have a direct or indirect relation to the type of gasoline you're using, so the MB dealership hasn't had to check your fuel tank yet.

Honestly, even though I'm not thrilled about MB's policy, I understand their position as a manufacturer (and the position of other manufacturers not "warranty-ing" repairs if there was a possibility of "misuse" or "use outside of manufacturer's specifications").

MB recommends Premium Gasoline for some reason, and writes it in their owners manual and on the fuel door so that people will read it and follow the instructions. If people use different grades of gasoline, then this increases the variables MBUSA and MB dealerships have to deal with, and the change may (or may not) have an impact on the vehicle's life, vehicle parts life, vehicle parts cleanliness, or other issues that may (or may not) happen depending on the vehicle (not enough study has been done on how non-Premium gasolines react in different vehicles that recommend it). Perhaps in some vehicles, there IS a MTTF and longevity issue... and in others there isn't. Perhaps to be on the safe side, MB recommends Premium Gasoline for ALL their vehicles, from the C-Class to SLR-Class, so they won't have to spend time finding out which vehicles are impacted by non-Premium gasoline, and which are not. I don't know.

But if you think about it, in a pinch this question could also relate to the type of oil used in the engine, or the type of coolent used, or type of transmisison fluid used, etc. MB (as all car manufacturers) would prefer if the same types of vehicles use the same type of gasoline, oil, coolent, etc so it would be easier for MB dealerships to work on and service, and because the vehicles tested and proven to react favorably with those combinations of gasoline/oil/coolent/fluids/etc. That may not be the case for other combinations of gasoline/oil/coolent/fluids/etc, thus MB can't (or won't) warrant how the vehicle will perform under non-recommended conditions. By limiting the possible combinations of fluids and parts used, MB limits their liability and the chance of different things going wrong.

 

Yes, I agree that MB dealerships shouldn't do that with fleet vehicles... and I'm sure there are some that don't follow this practice (as well as some that do). However, based on what the MB tech told me (about recommending 1 in 4 fill-ups being with Premium Gasoline), I'd imagine if the new owners of these vehicles followed directions and used Premium Gasoline (at least 1 in 4 fill-ups), then they should be OK in the future should any problem arise with their car (that is related directly or indirectly to the type of fuel used in the vehicle).

 

Interesting that MB doesn't specifically recomend Top Tier fuels that I've seen, get they recomend fuels with detergent. All fuel has some level of detergents mandated by the government, so how much is enough, they don't say.

What I found on a dyno with lower octane fuel is that performance suffers, about 12HP or so. The ECU will compensate for the lower octane by pulling back timing based on the knock sensor. Of course this depends on how much your car would knock and that varies by humidity, temperature, how heavy your right foot is. During the summer in So Cal where it's hot and very arid, I find that without running premium, you are going to lose a good amount of power and likely fuel mileage making it not worth the price difference on fuel. In the winter where its' cool and humid, it probably doesn't make that much of a difference.

 

Open your gas door and see what it recommends, unless someone peeled the sticker I guarantee it says "Premium Fuel Only", also check your manual... same story. Premium Fuel = 91+ octane. Unless I misunderstood, it looks like MB does recommend only top tier of consumer fuels.

 

Actually my 2005 had a series of fuel system issues around 35,000 miles that required the removal of the fuel tank and other parts. I took it to the dealership nearly empty and they needed to drive it a few days so they put fuel in it... 87 octane. I know this because I had to reimburse them for the fuel. $21.67 of 87 octane - I was given the receipt. I wasn't pleased about it, but then again, as I'll say once more - aside from a drop in performance and economy 87 octane is not harmful.

Given that you lose some performance (hey, the C230 needs every single one of it's 189hp) and mpg, it doesn't make financial sense to put in 87. But it isn't gonna break the car, either.

 

agreed.

In America the price difference on cheaper gas is not enough and shouldn't sway anyone to run other than 91 especially the FUBAR CA emission requirement that caused the 91 to suffer probably has the same actual rating as the east coast 89. consider most of you have the 230 which get you at least 28mpg x 16.4 gallon till empty = 459miles per tank. the current gas price difference of 20 cent from 87 to 91 (87 is $2.99 and 91 is $3.19 in my town right now) cost you about $3.28 per 16.4 gallon. and on avg most driver drives 15000 miles per year which divided by 459 miles per tank you would need 33 tank of gas. $3.28 x 33 tank = only $99 dollar a year approx. give or take depending on how you drive sometimes.

i don't know why the hell would anyone able save $99 a year and sacrifice the performance of your car.

even on my C32 which only gets 17mpg on avg IF i run 87 oct I would only save about $142 per year on my 12000 miles per year mileage.

I even put 91 in our 2005 Odyssey during the time we had it as a lease. it's always premium gas for me. I even put premium in the loaner if I have it for extended period of time that require me to fill it up.

 

Somewhere I have a copy of the email from one of the Atlanta dealers last year on this subject. Atlanta had a little gas shortage issue about this time last year, where we first had almost no fuel, then when the supply loosened up, you could only get 87 octane for about 5 weeks.

The short version of the email, based on my memory, was that 'except for AMG vehicles' temporarily running the 87 octane until supplies stabilize would not be a problem. I don't have an AMG, so it didn't bother me - and I believe I ran about 1/2 a tank of regular in the car during that time period.

Of course that is the only time it has had regular in it. I just put premium in everything, both cars and the motorcycle call for it, it just makes my life easier. I just don't get the idea of buying a vehicle that calls for it if you aren't willing to use it.

Speaking of fuel - is everyone else the 10 cents difference between each grade? Metro-Atlanta went to 15 cents between each grade when we got supplies back last year and it is still that way here...so premium is 30 cents a gallon more.

 

The engines in these cars is designed to use premium fuel to give the performance drivers expect, while keeping the CAFE high enough to meet the political obligations of the company.

Mercedes records data in the motor electronics that keeps track of you fellas that save $ 2 a tank full. They will deny warranty to those with octane related problem including those casued by detonation (broken pistons, bent rods, bent cranks, melted valves, and clogged cats.) and those caused by carbon fouling. They don't need to test the gas in your tank, just dump the data.

I love to read the testimonials about how people drove 200K with regular or midgrade, with no problem. How do they know there is no problem? Did they tear down the motor and inspect? Perhaps their driving style is such that they never see the needle above 3K RPM's and never more than 1/3 throttle, and never carry a passenger or anything heavier than a Strarbucks Vente. These guys also have a toilet paper oil filter, Seafoam in the crankcase, and a magnet on the fuel line. None of which has any benifit.

I can understand why dealers use 87. First, look up cheap in the dictionary it says "see new car dealer." They like to save the money. If that car returns for engine work later, on warranty or customer pay, that is considered good business. For Them.

The Mercedes engineers are telling you in the manual how to get a long life and good performing car. If that is not your objective, plesase use the regular.

 

Meh, I'm still not buying it. Doomsday scenarios like breaking a piston because of 87 octane are wildly unlikely. I guess they won't warranty it if an asteroid hits it while it's sitting outside, either.. oh well.

The car has sensors to protect itself. No one is advocating the use of regular unleaded. All I'm trying to do is do away with the rampant rumors that a drop of 87 octane is gonna kill your car.

 

Ive been using 93 octane on my 2005 C230 Kompressor since ive bought it and ive had no problems. Honestly if your driving a Mercedes, you should be using the highest octane possible unless otherwise stated in your cars manual.

Let me know if im wrong.

 

there's no problem with running lower grade gas except performance suffers and possibility of carbon built up in the LONGGGGGGGGGGGGGGGGGG run.

just remember Owner's manual are put together by corporate lawyers. It tells you don't do this and don't do that in order for them to avoid lawsuit and to make money on services for your car.