MBRedux

Listen to yourself then. No one is twisting your arm. No one really cares if you're not man enough to admit you've made a mistake, or that in all these years you have misinterpreted both the Mercedes OM and the USA/Canada pump ratings confusing them with the European RON standard as being one in the same... it's okay we understand. So keep going to the station and filling up with whatever you use, it makes no difference. Like I said earlier, no one really cares!

ohlord

***** up call your dealer and confirm 91 octane is RM2 method .Or even simpler refer to the page in your owners manual that I pointed out.
What we have here is a Welcher.
Do you even read your owners manual? 96Ron 86 Mon/2 method 91 octane minimum.
As far as no one cares. You sure seem otherwise
I'd expect the check cept you haven't the ***** to confirm the facts and pay off.
If I have failed to convince the dolts that grovel at your boots I certainly can understand their affection.

As for the 50K in your pocket that is as much a load of crap as your knowledge of Mercedes engines and fuel requirements. I'll make it easy on you though 50 bucks when you prove yourself wrong,okay....

sknight

Are you willing to escrow the money?

ohlord

Just needs to decide if he is a Welcher on $50K or $50 bucks
Either way I don't expect the pay off when he finds out he is wrong once again, as he is most times with MB related issues.
more of his costly sage advice
Go to the dealer because your exhaust smells like rotten eggs.....My ***

n8nu

What's the challenge?

As stated:

A Simple Chart / Mercedes Benz Octane Range for the GLK = 91-95 (RON)
USA/Canada 86(R+M/2) Octane Rated Fuels = 91 (RON) (That's if you can find it?)
USA/Canada 87(R+M/2) Octane Rated Fuels = 92 (RON)
USA/Canada 89(R+M/2) Octane Rated Fuels = 94 (RON)
USA/Canada 91(R+M/2) Octane Rated Fuels = 95 (RON)

So technically the GLK can take a min of 86/87 rated Octane. However using 91 Octane gas will improve performance and power.

So no problems using lower octane gas.

However the problem comes from Ethanol. And it seems that everyone agrees that Ethanol is the problem.

So can we not say, if you can find Ethanol free, 87 Octane gas you'd be fine? However you can't (or it's rare). In Canada and looks like a lot of places, the only Ethanol free gas is premium.

For me, I am keeping my car for a while and I bought it for it's performance. If I want it to drive and preform like a Mercedes, I am going to have to treat it like one...

ohlord

And I quote page 335 2010 GLK owners manual
" Fuels, coolants,
lubricants, etc.
Fuel tank All models 17.4 US gal (66.0 l) Premium unleaded
gasoline (Minimum
Posted Octane 91
[Avg. of
96 RON/86 MON]
Posted Octane 91
Fuel tank
reserve
All models approx. 2.1 US gal (8.0 l)
Fuel requirements
Only use premium unleaded gasoline. The
octane number (posted at the pump) must be
91 min. It is an average of both the Research
Octane Number (RON) and the Motor Octane
Number (MON): (RON+MON)/2. This is also
known as the ANTI-KNOCK INDEX.
Reformulated gasolines (RFG) and/or
unleaded gasoline containing oxygenates
such as ethanol, TAME, ETBE, IPA, IBA, and
TBA can be used provided the ratio of any one
of these oxygenates to gasoline does not
exceed 10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is not
allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used
! To maintain the engine’s durability and
performance, premium unleaded gasoline
must be used.
If premium unleaded gasoline is not
available and low octane gasoline is used,
follow these precautions:
Have the fuel tank only partially filled
with unleaded regular gasoline and fill up
with premium unleaded gasoline as soon
as possible.
Avoid full throttle driving and abrupt
acceleration.
Do not exceed an engine speed of
3 000 rpm if the vehicle is loaded with a
light load such as two persons and no
luggage.
Do not exceed 2/3 of maximum accelerator pedal position if the vehicle is fully loaded or operating in
mountainous terrain."
The same information from the 2011 owners manual?
With the added warning
at the top of page 297
! Do not refuel with low-grade fuel
Damage or malfunctions can result that are not covered
by the Mercedes Benz Limited Warranty
by an existing Limited Warranty
by an extended Limited warranty
The same information is also available on the Mercedes
Factory Approved Service Products booklet

Where's the confusion based on the facts?

MBRedux

Well I'll say one thing, you are persistent!

Just got off the phone with Mercedes Benz Technical. They are aware of the "misprint in the manual". Actually, according to them the misprint in the OM is with the use of the word "Minimum" and not with the averaged octane rating of 91 (R+M/2) that's listed, which is okay.

They claim that a "fix is in the works"! The addendum will read: PREMIUM UNLEADED GASOLINE 91 (R+M/2) Posted Octane Recommended, 87 (R+M/2) Posted Octane Minimum. That will bring the OM into full compliance with U.S. DOT/NHTSA/EPA standards & regulations and into full agreement with what's posted on the filler door of the GLK.

So it wasn't your mistake after all (even though most auto enthusiasts should know this stuff) but a misprint in the OM.

aggst1

Anyone know what they changed? My ML350 (same motor with GLK) requires the use of premium fuel as per the owners manual:
"Only use premium unleaded gasoline with a minimum Posted Octane Rating of 91 (average of 96 RON/86 MON). " It was mentioned earlier that a range is printed on the manuals. I wonder why they changed the requirement when the motor is identical.

sknight

Never trust Mercedes with the manuals. Remember the "lubed for life" autoboxes? Then they quietly began slipping in the change intervals for subsequent cars, despite being the same transmissions.

In this case, Mercedes likely messed up and the losses and problems they actually came back with were more than what the beancounters who run the company bargained for. They are trying to optimize the company on every end, shooting in the dark to eliminate every possible source of the problems with the cars, but not doing much about the engineering. It's GM engineering philosophy in more expensive iterations.

aggst1

Sorry but I see it the other way around. Never trust what people of questionable abilities say in public forums and instead trust what the manufacturer says in the owners manual.
The auto box was discussed on a couple of threads with similar "enthusiasm" you see on this thread.

MBRedux

Actually it's the reverse. You need to reference the fuel requirement sticker that's inside the filler door of the car when it was built and not the OM listing. The OM is misleading with regards to the "minimum" octane requirement. (The OM also has a disclaimer on the last page: (...Information, Illustrations and Descriptions in this Operator's Manual might differ from your vehicle.) ... which it does!

The sticker on the inside of the car's filler door should say as shown: 95-RON/ROZ (91-RON/ROZ Minimum) That simply means that in the USA and Canada which uses a different measuring standard that averages two separate rating systems, RON (the Research Octane Number) and MON (the Motor Octane Number) and divides the sum by 2... hence the R+M/2 tag seen on all gasoline pumps. (Please refer to my earlier posts) So any fuel sold here that's rated between 86 and 91 (R+M/2) pump octane will work in you GLK, but the recommended octane is still Premium 91 (R+M/2) or 95 (RON/ROZ). Technically, slow burning high octane fuels provide assurances that predetonation will not occur... and that's about it. No detonation equals better and smoother performance. No disagreement there. But you can still use lower grade fuels if needed, and here's why. It says so right on the car.

Please remember, the 91-95 RON ratings seen in the pix below are in the European RON/ROZ rating standard, with the American equivalent being 87-91 (R+M/2) pump octane readings.

(This pix is the inside of the GLK fuel filler door.)


Bottom line, you can use what you wish regardless of what anyone says. Onboard sensors will adjust the car accordingly. You may feel a TINY bit less power (although I doubt it) and your mileage may suffer a little (which ethanol also aggravates) but rest easy because the people who built your 3.5L engine placed a sticker on the car that says you can!

Sorry if that's confusing for those that refuse to comprehend something that's been around for a long, long time.

PS: RON and ROZ are the same.

sknight

You're jumping to assumptions. I don't trust Mercedes and I don't trust most people in this thread.

babyjocko

Uh...Doesn't the Bugatti Veyron use rocket fuel? I don't think that car should be a part of this ridiculous thread.

aggst1

Why don't you trust Mercedes? What are you implying here? That they mislead the public into buying premium fuel unnecessarily? And why they would do that? Oh i forgot, they get some kick back from the oil companies? Pathetic...

Of course you trust Mercedes! You trust them enough to put yourself and your loved ones in their product and drive!

EnigmaAW

is this the gas prices are going up and i'm whinning about it meeting?
hi...i'm anthony...um, i only use shell v-power gas, i fill up once a week, i don't care about gas prices!! and i'm sure my 22's aren't getting me the best gas mileage.....poor me!!

MBRedux

Actually the Bugatti Vyron requires an octane fuel with a rating of 98 RON/ROZ.

Link: http://www.bugatti.com/en/veyron-16.4/technology.html

That would mean if you were to bring in a uncertified Vyron into the USA, you would need an octane of 93-94 (R+M/2).

Here, read it for yourself, if you dare! Link:http://en.wikipedia.org/wiki/Octane_rating

Here's more to confuse you. From the above Wiki link.

Anti-Knock Index (AKI)
In most countries, including Australia and all of those in Europe, the "headline" octane rating shown on the pump is the RON, but in Canada, the United States and some other countries, like Brazil, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI, and often written on pumps as (R+M)/2). It may also sometimes be called the Road Octane Number (RdON) or Pump Octane Number (PON).

(So according to this, the AKI index is the same as the American/Canada (R+M/2) rating.)

Difference between RON and AKI
Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison. Click onto the above link to see the table.


So why do you find this rather common knowledge so "ridiculous"?

MKenM

First off I didn't promise you or anyone else $50 bucks. Second I didn't spend $50 K just to scrimp on gas. I said I use premium and I eat out 3 to 4 time a week.

You make a lot of ASSumptions.

My point is the Petro-Chemical industry at some point is going to want to use more corn than we can produce hence driving up the price of food because so many foods contain some corn derivatives.

The next time you want to call someone cheap, look in the mirror first.

MBRedux

In fact, take a look at these facts that I copied from a corn lobby document. The use of ethanol will SKYROCKET by 2022! So you're right!

sknight

Actually, that's a jump. A car goes from A to B. Later marketing turned people from using cars as tools to "you've entrusted us to get you and your loves ones there". Sorry, for me, a car is a tool. At this point, most cars are splitting hairs, in terms of differences in safety.

And I didn't imply anything. I said it directly. You used your own imagination to find what you wanted in my words, only exposing your own thoughts. If you want to know what my thoughts are, you could have thumbed up the thread and saw what I explicitly said about the european fuel situation, and how if the computers didn't have mapping for bad/low quality fuel, 100% of the cars here (and in the US) would have ruined engines. A car that runs out of fuel just because super isn't available, is a safety issue in Germany. A disabled car due to a low quality fuel problem without mapping to compensate is a safety issue. Knock sensors were partially developed to accomodate this and you folks are thinking Mercedes doesn't have it now, when even VW's and Audis had bad fuel accomodation in 1981? Some regressive technology, eh? We developed cylinder by cylinder knock sensing, faster computers, and distributorless ignition with independent cylinder tuning for better performance, only to completely forget how to program the computers for bad gas available in EVERY country in the world or a contingency plan when higher octane fuels are not available, as I frequently see in Germany and France?

buztech

What does the "picture" or logo of the fuel pump with a "diagonal stripe" across 2 letters : P and L (?) inside of the Benz fuel talk door? Next to the letters RON ROZ. What does that mean?

Thanks, just curious...

yualfred

Petroleum leaded?

packardbell

costco here only has two grades at their gas pumps, 87 and 91, nothing in between.
so according to your gurus putting 87 is fine just performance is not optimized.

MKenM

I guess you didn't read the whole thread but in any case why are you digging up old threads. Post something original or ask a worthwhile question. We will help if we can.

Kajnbabe

I've been using the mid-grade fuel which I believe is USA/Canada 89(R+M/2) Octane Rated Fuels = 94 (RON) and I've not to my knowledge had any problems. Runs the same since I got mine a year ago Jan 12. I run mid-grade b/c my sales representative told me it was okay to do so and that she always uses the mid-grade.

rgray80

Since when did finding ways to save money became so evil? Keep in mind that not everybody drive the amount as you do. I have a GLK and on occasion I fill up with regular gas to save money. I've experience No problems so far whatsoever.

If I only filled up my tank twice a month, then it wouldn't bother me to put premium all the time. However, I fill up my tank twice a WEEK (8x a month) so it gets pricey.

As of this positing, the price of gas is $3.47 for regular with premium being $3.88 ($0.41 extra per gallon). With a 17.4 gallon tank, the difference between the 2 grades is $7.13 per fill-up (or approx. 2 gal gas difference). Since I fill up twice a week, that's a difference of $14.26. And over the course of a month that's a $57.04 difference between the two grades (or ~16 gallons - nearly a whole tank of gas)!

So in your case, if all you're saving is $8 a month, then I agree, using premium all the time has very little impact. But when you're talking about a $57+ a month difference, the it becomes cause for concern. Maybe the original poster does alot of driving.

And no, the answer is not "well you shouldn't have bought a Mercedes in the first place!" Many people don't anticipate how much actual driving they'll be doing.