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Now that these cars are older what gasoline grade of fuel do currently use?


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1998 E320 base sedan @ 160kmiles
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Cheap gas fouls spark plugs and creates a lot of carbon build up. Saving $1.20 at the pump can mean thousands in repair costs down the line.

My E320 has 272k miles on it. When I bought the car from the PO she made a point to tell me that she NEVER, EVER, during the life of car from 2005 until now, used cheap gas. She literally went out of her way to tell me that.

Looking at the car service record and seeing the condition of the car, I can determine that line to be a complete lie.

I go by manufacturer specification.
There is a big difference between cheap gas, and the octane level. Ethanol (105 octane) is an octane booster, but it has less energy than gas itself. Tier-1 companies use other chemicals to boost octane which provides slightly higher energy boost. So some premium Tier-2 or 3 gas may perform worse than Tier-1 regular. Also where you buy gas makes a difference. Some gas local stations around me consistently sell bad gas, even they are Tier-1. Maybe it is something to do with their storage tanks, or their source. I don't know.
 

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1995 E320 Cabriolet
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55 Posts
Do you still run the manufacturer's recommended premium 91+ R+2/M octane fuel, or are you comfortable and had good luck with lesser grade fuels?

This is not to start a heated discussion as some are very opinionated on this topic, (such as what oil they use!) so please be respectful and any comments on any differences you have noted if you have chosen to try a grade other than the manufacturer's recommended fuel would be interesting.
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There is absolutely no benefit to premium fuel at any point in a vehicle’s life. It will not improve mileage, longevity or performance.
Do you still run the manufacturer's recommended premium 91+ R+2/M octane fuel, or are you comfortable and had good luck with lesser grade fuels?

This is not to start a heated discussion as some are very opinionated on this topic, (such as what oil they use!) so please be respectful and any comments on any differences you have noted if you have chosen to try a grade other than the manufacturer's recommended fuel would be interesting.
There is absolutely no benefit to using premium fuel at any point in a vehicle’s life. It will not improve mileage, performance or longevity. They do contain extra detergents but there is no evidence that they provide any real benefit. I have never used premium in any of my cars with no problems whatsoever with knocking or any other related issue. You won’t either. If you’re superstitious, but mid grade
 

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1999 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
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2,653 Posts
Have owned Mercedes for over 30 years. Driving on flat, sea level roads, I burn Regular Unleaded in all but my SL550. Waste of money to go premium octane, but always buy high quality fuel.
Why the exception with the SL550? If you really believe in what you say, make a full commitment.
 

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2002 E55 AMG Sedan
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1,159 Posts
Premium gas doesn't have more detergents than regular or mid. They all have the same detergents. That's a common myth. The only difference with detergents in the gas would be from different brands (no name vs brand name)
 

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1995 E320 Cabriolet
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55 Posts
Cheap gas fouls spark plugs and creates a lot of carbon build up. Saving $1.20 at the pump can mean thousands in repair costs down the line.

My E320 has 272k miles on it. When I bought the car from the PO she made a point to tell me that she NEVER, EVER, during the life of car from 2005 until now, used cheap gas. She literally went out of her way to tell me that.

Looking at the car service record and seeing the condition of the car, I can determine that line to be a complete lie.

I go by manufacturer specification.
Actually ‘cheap gas’ does no such thing, if by that you mean regular since most gas is the same regardless of what you pay at the pump. Your car would have 272 K if you’d used regular or mid-grade and you’d have more money in the bank.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Ok, remind me to never buy cars from you.
 

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W221 & Audio Moderator
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Discussion Starter #33 (Edited)
There is absolutely no benefit to using premium fuel at any point in a vehicle’s life. It will not improve mileage, performance or longevity. They do contain extra detergents but there is no evidence that they provide any real benefit. I have never used premium in any of my cars with no problems whatsoever with knocking or any other related issue. You won’t either. If you’re superstitious, but mid grade
It can, and does improve performance if the vehicle is designed to take advantage of it. Forced induction vehicles in particular need the higher octane level to achieve the post output figures, and to allow, for example, the M112 generate the output that MB publishes, the vehicles timing must be advanced accordingly therefore increasing the potential for knocking to occur. The ECU is designed to pull out some timing knock is detected, so the likelihood if engine damage is low, but when this timing is backed off the power output will noticeably be lower, particularly in the high RPM range under moderate to heavy acceleration.

Based on your statement, I am just curious what your theory is as to why they demand premium fuel? And do so in no uncertain terms (which I do believe to be excessively specific “if premium fuel is not available and refueling is required, use the minimum amount of regular fuel required to reach a location that provides the specified fuel and fill the tank with the correct fuel, not exceeding 3,000RPM or accelerating more thank half throttle.” That is paraphrased but is close to what the manual specifies.

I think there is little doubt that Mobil used to pay MB a decent amount to affix the “Mercedes-Benz recommends Mobil 1“ label under the hood, and oil manufacturers probably pay a lot to become MB Sheet certified to be allowed to put that on the containers of their product, but as far as the petroleum industry paying MB to recommend premium fuel due to the higher profit margins I am not sure would be plausible.

It is beneficial for automotive manufacturers to advertise that premium is not required in their vehicles, such as Ford doing just that for their Ecoboost line of engines, with the disclaimer that advertised power output is achieved using premium fuel. I cannot see Mercedes-Benz finding it beneficial, unless they feel it supports the vehicles target market as being “exclusive” and thus “the best engineered cars need the best fuel to operate then” type of mentality.
 

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1995 E320 Cabriolet
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55 Posts
Ok, remind me to never buy cars from you.
All



Ok, remind me to never buy cars from you.
All the MB I’ve ever owned had over 250k when I sold them and we’re still going strong despite the fact that I never used an ounce of MB brand fluid in any of them. I’ve owned a few exotic sports cars in my day that required pampering but a W124 is by no means exotic. It was a mass produced vehicle designed for a nice daily drive. I started a business in Germany in the 1990s and owned a 1988 E320 at the time.i sometimes asked the taxi drivers, all of whom drove W124s, if they were careful about using MB fluids, since when I priced them thought they were wildly expensive. I got several laughs but never a ‘Yes.’
For some reason, Americans have been led to believe this vehicle is more finicky than it is and won’t run long and true unless everything they put in it comes from the dealer. That’s simply not true but it’s a myth many cling to. Thankfully my local mechanic, who worked for the company for a number of years, doesn’t believe the hype either.
That’s all I have to say. Won’t clog up this thread any longer,
Cheers.
 

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E320/E250 Bluetec Ford F350 6.7l
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You are comparing different technology.
When 4-cylinder turbodiesel back in 1990 would deliver 75 HP, the last decade models deliver 200 HP.
I posted pictures in the past where W124 diesel, who run 270k miles on dino oils still had honing marks on cylinder walls, meaning the engine was still in break-in period.
Now go to diesel section on parallel forum and read how 2010 era diesels seized only becouse dealer put in them oils design for cars build in year 2000
It is right that for flat driving and no acceleration regural gas will be fine. But driving on West Coast, I have several grades who can be 18 miles long, so years ago, driving Volvo design for regural, I was filling it with Premium, even at the time it was 30% more expensive.
Thank to Premium - Volvo would take those grades without downshifting, what helped avoid overheating, was more comfortable and suppose to save lot of fuel as well, although at the time cars did not have computers showing mpg.
 

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1995 E320 Cabriolet
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55 Posts
Does the higher octane gas have more energy than the lower octane one (fluid ounce-by-ounce) ?
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Regular gas creates a lot of carbon build up, to the point where it will plug up the secondary air passageway in the head and foul up the spark plugs.

I should know, I'm dealing with both of these from the &#&@* previous owner.
Doubt that was the cause. No evidence fuel octane would cause that
 

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1997 MBZ E420, 208k miles
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We seem to be forgetting what octane is designed to do. Reduce preignition and knock which is very damaging to an engine.
So let's be clear, cheap no name gas REGARDLESS of octane rating will have fewer detergents than Tier-1 gas and will eventually cause carbon buildup and hotspots in the combustion chamber.
Tier-1 gas is supposed to burn "cleaner" and leave fewer of these deposits behind.
As my understanding of compression ratios goes, the higher the ratio the higher the chance for preignition and knock. Generally speaking, your typical econobox with a 9.5 to 1 compression ratio will run fine on 87 octane gas. According to KBB specs, my 97 e420 has a compression ratio of 11 to 1. That's high performance muscle car territory. My car has 210k miles and runs like a champ.
So yes, I stick with premium 91 octane from a Tier 1 gas supplier and I NEVER, EVER, EVER fill up at Arco, EVER!!!!
 

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1995 E320 Cabriolet
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I’ve owned several Mercs that went 210k plus without using premium so your car proves nothing more than mine does. Your argument is also a bit beside the point. The question here isn’t about ‘cheap’ gas at all. It’s about regular vs premium. Chevron regular is not cheap gas it’s just cheaper than premium
 

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1997 MBZ E420, 208k miles
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I was simply trying to steer the thread back to the octane level debate. I've only owned my car for 6k miles but the advertised compression ratio (if it's accurate) warrants premium fuel.
 

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1996 SL500, 2000 E430
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I read sometime ago in one of Chevron's ads that their supreme had a bit more Techron additive than the regular. You can also buy their additive separately - and if you have been using a cheap gas - not Top Tier - dump a bottle of that in your near empty tank, fill it up, and drive until nearly empty. If your car has carbon, you will notice the oil getting black after that tank.

Having pulled a cylinder head on my M103 at 155,000 I have seen how Techron works as the piston tops had very little carbon - you could see the aluminum.

I suspect any Top Tier gas would be similar.

As to the claim that any grade is the same - there is a reason for different octanes. Since the 90s, you won't hear any "pinging" (fuel detonation before the piston reaches TDC), because of knock sensors, They will sense the beginning of a detonation and retard the timing - spark plug firing later as the piston is closer to the top (TDC). Less power and lower economy.

If the car isn't supposed to use 91 octane, putting it in will make no difference, but putting in a lower octane in a car designed for premium will be noticeable.

Years ago a woman who had a Lexus - I think it was the mid range - asked me why her car felt so sluggish. I put 91 octane in and the difference was amazing - imagine that you suddenly have another 50 hp in day to day driving.

And I'm with Deplore - have always used (for me) Chevron Supreme - don't care if I spend a few more dollars. I know the engine is as clean as it can get and giving all the power (and economy) it can.

If the owner of that SL550 put regular into a near empty tank I'll bet the difference would be shocking.

There's a reason the factory tells us to use premium - they were designed for it.

I don't understand the logic of putting in a lower octane fuel simply because the car is old and worth little.

Probably why a large percentage of W210s today are - garbage. They are worth little and people don't want to spend the money giving them the care they require.
2620744

Not mine.
 
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