Roadhog56

Reading over the information in the manual and it call for 93 Octane fuel. Has anyone used Regular Unleaded or stuck with the Unleaded Premium. I also have a 2014 E350 and have always ran Regular Unleaded and have had no problems.

Thoughts?

Philamg

In the UK it tells you what octane fuel to use on the fuel filler cap.

GregW / Oregon

Read my post and related ones here: https://mbworld.org/forums/gle-class...ml#post7775118

That is a poor idea, IMO. The car will run, but you are giving up performance, economy and will have a dirtier engine in the long run (both internally, and with emissions). The engineers spent a lot of work optimizing the engine, and you are compromising it. The manual recommends against using low ocatanes on a regular basis for reasons. Use Premium. This is not an cheap econobox.

edofloat

I read your other post, it says in the selection of the manual you posted “if you want maximum engine performance” use 91 or 95. Then it explains if you use regular fuel to only fill half full. My GLE is in order purgatory for now so I can’t look. What does it saying the fuel door or cap? Required?

I get that you may loose some power and fuel economy because the engine can further advance the ignition to get more power from the engine with higher octane fuel. The fact that it is able to do that seems to indicate the module controlling the engine can vary timing based on octane somehow. To avoid paying out lots of warranty claims it seems that the manufacturers have figured this out in terms of fuel grades. Seems like a way to protect themselves against the consumer.

bigpern23

I agree with Greg, particularly since whatever little bit of money you save on fuel, you'll probably end up putting 10 times or more into unnecessary repairs/maintenance on the back end. If you drive 10,000 miles per year and average 25 miles per gallon, you're putting 400 gallons of fuel in your car. Here in New England, regular octane fuel usually runs about 50 cents per gallon cheaper than premium. Even if the car maintained its fuel economy, which it wouldn't, you'd save about $200 a year, at best. Not worth the potential negative effects on your engine, IMO.

guitarplayer

If you can’t afford premium fuel which is required, perhaps you should look at an American made suv.

Philamg

I thought the GLE was American made!.

guitarplayer

You know what I meant. German engineering vs a cheaper Chevy, GMC, Ford.

Come on, if you are too cheap to use the required premium fuel, perhaps a Ford Escape would be a better fit. You can even take it to Jiffy Lube with a coupon and save on maintenance.

GregW / Oregon

Yes, of course the engine can adapt, at the expense of some fuel economy (offsetting any cost savings) and performance. As someone with a Ducati 1299 I would think you would care about getting all the performance you paid for. The other thing is higher fuel grades contain more additives to keep the valves and other engine internals clean. But, you sound like one that leases so doesn't care about that.

You mean, protect the consumer against themselves? So here you seem to indicate you think using regular fuel can damage the engine. I'm not sure if physical damage is a possibility, but you are doing the engine no favors.

Also, as a general rule, if you already read the other thread where this subject was discussed, you should add to that instead of creating a new one. That way thread clutter is reduced and relevant information is together.

Lanzz

I wouldn't rule out the possibility of engine damage using lower octane fuel - under heavy load and hot ambient conditions, there's a ton of stress on any forced induction engine. I also believe that in the event of a mechanical issue, there is some way for the service tech to discern the octane of the fuel being consumed at the time of the issue - I definitely don't want to be having that conversation for an extra $10 per week in premium fuel cost.

marchgroupinc

Higher octane levels can also mean more ethanol which has not been discussed here, but is related to the topic. I do not like to have ethanol in any of my gas engines due to the problems it creates. I purchase ethanol free - which in my market (Ontario Canada) means premium fuel only available at Shell. 91 octane is the highest they offer. All other brands of all grades and octane levels here have ethanol of 5 - 10%. I don't currently have a gas Mercedes (waiting for a GLS580) so I can't say what MB recommends with regard to ethanol. I am curious what the octane level MB requires for Canada - 91 is normally the highest octane offered here. From my travels, many States have some ethanol content in their gas. What does MB state regarding ethanol percentages?

GregW / Oregon

10% ethanol maximum.

tiri

Petro Canada has Ultra 94 and 91 octanes.
Generally speaking, in Quebec, Esso, Ultramar, Shell, Irving, etc. all sell 91 octane without any ethanol added. All brands are supplied from the same refinery, and then the additives are combined at the ramp, then delivered to the stations.

Philamg

In Uk we have 95 octane and 98/99 octane, the fuel filler cap says 95 octane.

GregW / Oregon

Europe and much of the world use RON, while the US & Canada use AKI; different indexes. AKI runs 4-6 points lower than RON. The US octanes run in a range of 87-93 AKI.

GregW / Oregon

This is from a US 450:

edofloat

Thanks! I normally buy 91 for the GLC and always for the Ducati (with no ethanol). I will say in winter if 91 is offered without ethanol (some stations have both types of 91 and others do not here) I will put in 89 (E10) when its really cold and keep the tank quite full as well.

Philamg

UK FILLER CAP

SmokinBuddha

If buying Super or Premium gas for your GLE is an issue, maybe you should be driving a Toyota, Hyundai or any other non luxury car than Mercedes.

Chip Mason

Mercedes V6 are high compression engines, vs Toyota, Honda, etc. Because of this, you need the fuel to be less likely to detonate early, so that full compression can proceed before detonation. Using lower octane fuel means that the fuel:air mixture will detonate before full compression is reached, ie before the cylinder reaches the top of the stroke (also known as knock). This will reduce efficiency, power and lead to damage to the engine. The computer will attempt to retard or forward timing to compensate.

Using higher octane in lower compression engines really has no impact, since there is little advantage. But in a higher compression engine, lower octane fuel can lead to damage or at the very least lower gas mileage, as you are not getting the full power from each cycle.

sno

93 FTW the car runs better plain and simple. Yes these days fuel cost are high and there is no signs of slowing but that is what you sign up for when you purchase vehicles with high compression engines. Power costs money

ArchHist99

If you REALLY want to get crazy, try ethanol free (AKA recreational) fuel! Our Service Manager mentioned it to us and we found a Sunoco and RaceTrac near us that have it. The GLE 63S runs noticeably smoother without the ethanol (AKA corn&#127805 in it. It does cost more than premium but it does make a difference!

Imanone

The poster asked a simple question about fuel grades and you had to respond as an arrogant snob. I guess we all should be impressed that you have a Mercedes and use premium gas. Congrats to you!!

mikapen

Thanks for that post. There have been several posters on this thread who want to make snide comments about heritage or wealth, but have no real information to share. Methinks they must have some sort of "complex."

Ron.s

Plus it has more energy in a gallon so you get 1-2 mpg better mileage to help offset the increased price-not that it matters much. I run Non Ethanol in my toys and lawn/garden equipment but our 91 Octane sources are inconvenient or require a card lock commercial account. The Non E fuel is stable over long periods vs dangerous phase separation (to the engine) can occur with Ethanol if it sits for a long time. I might try a few tanks in my 53 to see if there’s any noticeable difference.