GL 450 and Premium Gasoline
Thread Starter
Newbie
Joined: May 2007
Posts: 23
Likes: 0
From: San Diego, CA
GL450
GL 450 and Premium Gasoline
Does everyone us 91 octane in their 450? Just wondering if their are actually notable or specific advantages/disadvantages to doing so. Better gas mileage, noniminally more response or power, or is it just a good way to spend 5-7 bucks more per fill-up?
Senior Member
Joined: Mar 2007
Posts: 379
Likes: 0
From: MA
13 SL550, 14 E63 Wagon, 15 S550, 11 M3, 08 F430 Spider, 12 ML350
$5-$7 extra for Oil Execs. Using higher octane values than required for a particular engine provide no additional power or mileage. The higher octane is only required for increased compression ratios to avoid knock. That being said I think there are differences between brands posting a given octane. I use 91 normally or 93 if available at a "crap" brand if I'm stuck.
MBWorld Fanatic!
Joined: Mar 2007
Posts: 1,653
Likes: 7
From: Central Pa.
2013 GL450 (traded for 2015 Escalade), 2012 Corvette, 2014 Ford Fusion, Previous: 2007 GL450, 2011
In past experience I have found that when the manual "reccomends" higher octane fuel.....it really does not need it. BUT when the manual "requires" higher octane ( which seems to be the case in most German V8's and most high end Japanese cars ) you had better use the higher octane. Had a VW Touareg for a while........required premium.....I tried lower octane......it definitely did not run as well!
Member
Joined: Mar 2006
Posts: 199
Likes: 0
From: South Carolina, USA
06 CLS55, 07 GL450, 07 GMC Yukon, 06 Pontiac Vibe
I have used lower octane a couple of times. It cut off once after start-up, and you get a little hesitation occassionally. But nothing huge. So now I go back a forth between fill ups.
Senior Member
Joined: Apr 2004
Posts: 254
Likes: 4
From: N. Illinois, USA
2021 GLS450, 2015 E250BT 4Matic, 2007 GL320CDI, 2005 SLK350, 2001 SLK320
My wife's RX330 "recommends" premium. We use 87 octane with no ill effects at all. My SLKs "require" premium and I've never used anything less than 91 octane.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Newbie
Joined: Jan 2007
Posts: 9
Likes: 0
From: Las Vegas
'07 GL450, '05 Accord Hybrid, '95 APU 6spd Supra
Using sub-91 octane should be fine especially due new technology these days. The OBD2 computer automatically retards the timing when sensors pick up signs of detonation and this helps prevent detonation. Keep in mind though that lower octane fuel increases the chances of detonation (knock) especially in high compression vehicles. If the computer always retards the timing to avoid knock, then your car will not produce the same amount of power. With the GL's compression ratio being 10.7, higher octane fuel is recommendable for peak performance to be achieved.
Super Member
Joined: Jan 2007
Posts: 537
Likes: 2
From: Land of Magnolias and Mint Juleps
What effects, if any, would using 89 or 87 octance fuel have on warranty coverage? Could MB deny a warranty claim for engine repair if they found 87 octance fuel in the tank when the owner's manual clearly states the higher octane requirement? 
FWIW, I use Chevron 93 octane.
FWIW, I use Chevron 93 octane.
Thread Starter
Newbie
Joined: May 2007
Posts: 23
Likes: 0
From: San Diego, CA
GL450
Thanks for the technical explanation CIEREX. I appreciate you explaining that to us. I am glad to know that there is a solid reason that it requires a higher octane fuel, other than just to be special or different. Over time it adds up paying for premium versus regular but it is most likely worth it from what I keep reading. At least I will be travelling a lot less on a daily basis when I get to California.
MBWorld Fanatic!
Joined: Apr 2003
Posts: 4,781
Likes: 3
From: Boston
'05 A4 1.8TQM6
Newbie
Joined: Jan 2007
Posts: 9
Likes: 0
From: Las Vegas
'07 GL450, '05 Accord Hybrid, '95 APU 6spd Supra
What effects, if any, would using 89 or 87 octance fuel have on warranty coverage? Could MB deny a warranty claim for engine repair if they found 87 octance fuel in the tank when the owner's manual clearly states the higher octane requirement?
Super Member
Joined: Jan 2007
Posts: 537
Likes: 2
From: Land of Magnolias and Mint Juleps
The only way that 89 or 87 octane gasoline can void the warranty is if the gasoline itself caused the problem. Lets say that the engine detonates due to low octane gasoline, then all the repairs will not be covered by the vehicle's warranty. But lets say that your transmission gives out while you have 89 or 87 in your vehicle, repairs should be covered by the warranty since the gasoline did not directly cause the problem.
Thread Starter
Newbie
Joined: May 2007
Posts: 23
Likes: 0
From: San Diego, CA
GL450
I like how this has gone on into a little thought experiment about warranty coverage etc...
But, does the dealership that would be doing warranty repairs for some type of potentially low grade fuel caused wear and tear or mechanical breakdown have the proof that the lower grade fuel caused said mechanical breakdown or wear and tear?
How would they test the fuel to see what octane level it is. I am not being sarcastic, maybe it is simple to do, but if they tried to say that my low octane fuel caused damage and voided my warranty I would argue that the only way low grade fuel made its way into my tank was through faulty advertising at a gas station, or an accident where the fuel tanker filled the wrong subterranean tank with 87 octane, and I was sold a misadvertised product.
But, does the dealership that would be doing warranty repairs for some type of potentially low grade fuel caused wear and tear or mechanical breakdown have the proof that the lower grade fuel caused said mechanical breakdown or wear and tear?
How would they test the fuel to see what octane level it is. I am not being sarcastic, maybe it is simple to do, but if they tried to say that my low octane fuel caused damage and voided my warranty I would argue that the only way low grade fuel made its way into my tank was through faulty advertising at a gas station, or an accident where the fuel tanker filled the wrong subterranean tank with 87 octane, and I was sold a misadvertised product.
Newbie
Joined: Jan 2007
Posts: 9
Likes: 0
From: Las Vegas
'07 GL450, '05 Accord Hybrid, '95 APU 6spd Supra
Could MB claim the low octane fuel being used directly caused the problem and deny warranty coverage? My guess is they could and the owner would be SOL.
)
How would they test the fuel to see what octane level it is.
MBWorld Fanatic!
Joined: May 2004
Posts: 1,093
Likes: 0
From: California
2014 C250 sport
These new DOHC V6 and V8's definitely should be run on premium 91 octane. All of the C230 V6 loaners I have had obviously get regular, 87 octane gas put in them, and they ping BADLY. The old SOHC V6's and V8's rarely would ping on regular gas, but these new ones have a higher compression ratio. Even though the ECU does compensate some, there is still pinging. use premium!
Junior Member
Joined: May 2007
Posts: 41
Likes: 0
From: Weslaco,Texas
2023 S500, 2002 Ferrari 360 Modena Coupe, 2012 Ferrari FF
We all paid a large sum of money to own a GL, why are we trying to use a lower grade fuel,to get by? Wait until tire replacement is needed, this all comes with "The Territory". 
Super Member
Joined: Jan 2007
Posts: 537
Likes: 2
From: Land of Magnolias and Mint Juleps
Senior Member
Joined: Mar 2007
Posts: 379
Likes: 0
From: MA
13 SL550, 14 E63 Wagon, 15 S550, 11 M3, 08 F430 Spider, 12 ML350
How true, for me, 15,000 mi/yr, 18 mpg, 35 cent diff reg vs prem = $300/yr.
MBWorld Fanatic!
Joined: Mar 2007
Posts: 1,653
Likes: 7
From: Central Pa.
2013 GL450 (traded for 2015 Escalade), 2012 Corvette, 2014 Ford Fusion, Previous: 2007 GL450, 2011
MBWorld Fanatic!
Joined: Mar 2007
Posts: 1,653
Likes: 7
From: Central Pa.
2013 GL450 (traded for 2015 Escalade), 2012 Corvette, 2014 Ford Fusion, Previous: 2007 GL450, 2011
Actually OE replacement tires ( Continentals or Dunlop ) are readily available and less costly than I thought they might be.............just don't try to find "winter tires" for the GL.............they don't exist at any price
