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Old Mar 24, 2011 | 01:50 PM
  #101  
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I think that one should always follow the recommended fuels specified in the owners manual. That said, with the modern electronics and sensors in cars of the past 10 years, it is unlikely running lower grade fuels will cause any permanent damage in any way, shape, or form, unless there is a total failure of the ECU or sensors feeding it. Now, you kids pick up your toys and head to bed....
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Old Mar 29, 2011 | 10:42 AM
  #102  
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Page 8 of the Maintenance Manual for my 2010 states "Damage to the engine could occur if premium unleaded fuel is not used." Also, "Use only premium unleaded gasoline with an anti-knock index of at least 91." 'Nuff said.
The M-B manuals that came with my car list far more reasons why the warranty could be voided than any other car I have owned.
BTW, I contacted MBUSA and they approved adding Techron periodically to gasoline models. In fact, my dealer includes it as part of their regular service on gasoline models.
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Old May 9, 2011 | 06:58 PM
  #103  
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I'm soaking all of this in, and find it interesting. There's a couple of things missing, however.

First, let's hear from someone who has experienced damage to his or her engine from running 87 octane gas.

Also, everyone here assumes we are all driving $50k cars. According to Blue Book value, mine is worth approximately $14k. I personally wouldn't be able to afford it if it were a $50k car, so yes, the small amount of money saved by not buying premium would mean something to me. (I haven't run less than premium yet. Yet is the key word.)

I can't imagine that MB would sell a car that can't run on 87 octane without damage, unless they only sold them in locations where gasoline quality is guaranteed.

I had a 96 Pontiac Solstice with a 177 horsepower Ecotec engine. It was a higher performance version of the engine that year, and the owner's manual said it would run at peak performance with 93 octane gas, but that 87 was just fine. I'm not going to believe that GM engineers could pull this off with this engine while MB could not.

My belief is that the 4.3 V8 in my E430 would run just fine on 87 octane, as long as it was good quality fuel. If not, then shame on MB. I think Porsche summed it up by saying their cars would be sold all over the world. If MB truly had a problem with 87 octane fuel, we'd hear about it all over the place, and their reputation for quality and reliability would suffer immensely.

Now, let's hear from someone with verified engine damage.

Last edited by dmwil; May 9, 2011 at 07:07 PM.
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Old May 9, 2011 | 07:03 PM
  #104  
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Originally Posted by dmwil
I'm soaking all of this in, and find it interesting. There's a couple of things missing, however.

First, let's hear from someone who has experienced damage to his or her engine from running 87 octane gas.

Also, everyone here assumes we are all driving $50k cars. According to Blue Book value, mine is worth approximately $14k. I personally wouldn't be able to afford it if it were a $50k car, so yes, the small amount of money saved by not buying premium would mean something to me. (I haven't run less than premium yet. Yet is the key word.)

I can't imagine that MB would sell a car that can't run on 87 octane without damage, unless they only sold them in locations where gasoline quality is not guaranteed.

I had a 96 Pontiac Solstice with a 177 horsepower Ecotec engine. It was a higher performance version of the engine that year, and the owner's manual said it would run at peak performance with 93 octane gas, but that 87 was just fine. I'm not going to believe that GM engineers could pull this off with this engine while MB could not.

My belief is that the 4.3 V8 in my E430 would run just fine on 87 octane, as long as it was good quality fuel. If not, then shame on MB. I think Porsche summed it up by saying their cars would be sold all over the world. If MB truly had a problem with 87 octane fuel, we'd hear about it all over the place, and their reputation for quality and reliability would suffer immensely.

Now, let's hear from someone with verified engine damage.

+1.
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Old May 9, 2011 | 09:02 PM
  #105  
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Originally Posted by dmwil
First, let's hear from someone who has experienced damage to his or her engine from running 87 octane gas.
The manual for the 2011 E Class Sedan states clearly that 91 grade premium fuel *must* be used.In contrast,I've owned two Infinitis equipped with their well known 3.5 litre V6.The manual of both those vehicle (an '03 and an '07) stated that premium was *recommended* for maximum performance but it clearly stated that regular 87 grade could be used without harming the engine.

I'm no mechanical engineer but the two engines...three,actually...an Infiniti V6,a Mercedes V6 and a Mercedes V8...seem to have substantially different needs.I,for one,wouldn't take the risk of using anything less than 91 grade.
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Old May 9, 2011 | 09:43 PM
  #106  
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In Australia 91, 95 and 98 Octane petrol is available.

I am not sure if we have the same rating system but the 550 motor says 95 only. When it was first introduced the recommendation was reported as 98 only (same as still required for AMG).

I would only put a lower rating in as an emergency "get you home from the bush" measure.
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Old May 9, 2011 | 10:24 PM
  #107  
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Originally Posted by dmwil
First, let's hear from someone who has experienced damage to his or her engine from running 87 octane gas.

Now, let's hear from someone with verified engine damage.

Ok my friend how about you go buy a $60k 2011 E350 run nothing but 87 then come back and tell us all about it?

I ran into the same scenario with having to buy the cheap stuff but this time I was on my bike. And the bike did not like the cheap stuff at all, I may have noticed it because on a bike you are basically sitting on the engine while in a car you are isolated from the engine and especially the W212 where the driver is more isolated from the engine than most ordinary cars. My point is that if you are dumb enough to be putting the cheap stuff in your W212 then your car may be running like $h!t and you don't know it.
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Old May 10, 2011 | 12:01 AM
  #108  
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Originally Posted by Tjdehya

Ok my friend how about you go buy a $60k 2011 E350 run nothing but 87 then come back and tell us all about it?

I ran into the same scenario with having to buy the cheap stuff but this time I was on my bike. And the bike did not like the cheap stuff at all, I may have noticed it because on a bike you are basically sitting on the engine while in a car you are isolated from the engine and especially the W212 where the driver is more isolated from the engine than most ordinary cars. My point is that if you are dumb enough to be putting the cheap stuff in your W212 then your car may be running like $h!t and you don't know it.
While I haven't yet run 87 octane, I'm becoming convinced that the recommendation to run 91 is nothing more than stroking the egos of people who paid $60k for their cars. It is all about who they are marketing to.

Do you really think they would sell a car all over the world that would be ruined by 87 octane gas? I don't. If they did, then I don't think their engineering would be worth $60k.

I might be wrong. Therefore, I'd like to see an example of a car with engine damage. My car has had 87 in it when my wife accidentally filled it. She didn't know. (I'm sure she's done this several times.) How would you feel about MB if your 60k car was ruined because your spouse or child didn't know any better? My money says these things are filled with 87 octane all the time and they run just fine.

My opinion is that there would be no excuse whatsoever for MB to engineer a car that can't operate on regular octane fuel without damage. Not in this day and age with the technology available. Not when GM can do it with a $20k Solstice with a little 4 banger. I've got more confidence in MB's engineering than that.

Again, I think this is marketing and ego-stroking. Think not? Then why all the fuss about "my $60k car!"

I love the line about my engine running like ***** and me not knowing it. If I didn't know it, I'd say it would be running fine.
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Old May 10, 2011 | 12:28 AM
  #109  
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Originally Posted by dmwil
I'm soaking all of this in, and find it interesting. There's a couple of things missing, however.

First, let's hear from someone who has experienced damage to his or her engine from running 87 octane gas.

Also, everyone here assumes we are all driving $50k cars. According to Blue Book value, mine is worth approximately $14k. I personally wouldn't be able to afford it if it were a $50k car, so yes, the small amount of money saved by not buying premium would mean something to me. (I haven't run less than premium yet. Yet is the key word.)

I can't imagine that MB would sell a car that can't run on 87 octane without damage, unless they only sold them in locations where gasoline quality is guaranteed.

I had a 96 Pontiac Solstice with a 177 horsepower Ecotec engine. It was a higher performance version of the engine that year, and the owner's manual said it would run at peak performance with 93 octane gas, but that 87 was just fine. I'm not going to believe that GM engineers could pull this off with this engine while MB could not.

My belief is that the 4.3 V8 in my E430 would run just fine on 87 octane, as long as it was good quality fuel. If not, then shame on MB. I think Porsche summed it up by saying their cars would be sold all over the world. If MB truly had a problem with 87 octane fuel, we'd hear about it all over the place, and their reputation for quality and reliability would suffer immensely.

Now, let's hear from someone with verified engine damage.
You clearly haven't read through this whole Thread, please do so, so you don't come in here asking us to spin our wheels all over again.

With knock sensors, timing retarders, etc. you probably will NOT "blow your engine" by using 87. But you WILL be using gas that WILL force your engine to retard itself, as that gas WOULD lead to engine failure without computers compensating for it.

On top of that, the engine will NOT perform at its optimal level with less than 91, and I'm not just speaking on a performance level, and it WILL get worse gas mileage, so you WON'T actually save those precious pennies at the pump, like you think you will.

By using 91, you WILL be doing a good service to the next owner (considering they will treat the car like it was meant to be treated).

M-B is in the business to sell cars, and if they had this "ego", they wouldn't put out a 268 HP V6 that requires 91, when competitors offer higher HP for less $$ cars. They know VERY well that many owners will NOT buy a car due to requiring the "expensive stuff", and they wouldn't make it a *requirement* unless it WAS a *requirement* for the engine to perform optimally, have optimal reliability, and get *optimal Gas Mileage* to use 91+.

Again, we all like saving money, and I'll pinch as much as I can, but if you buy a car that REQUIRES 91, stop being a cheapo and use what's required, or else buy another car. There are others that have more HP, and/or better Gas Mileage, that might be designed to operate optimally with less than 91.
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Old May 10, 2011 | 12:51 AM
  #110  
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Originally Posted by dmwil
I love the line about my engine running like ***** and me not knowing it. If I didn't know it, I'd say it would be running fine.
Holy Crap, that was my point GENIUS! READ the f-ing thread. I had no choice but to put 87 in my car at one point... the car ran fine. I had no choice but to put 87 in my bike and the bike ran like crap. So my possible conclusion was.... Drum roll... I didn't know it so I assumed it was running fine. You seem to be lacking any sense of thought or reason so you have become #2 on my ignore list. Please feel free to add me to your... Please.
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Old May 10, 2011 | 09:40 AM
  #111  
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Some years back, Subaru was experiencing issues with their engines if HIGHER octane than recommended was used. Due to the higher octane fuel's higher ignition suppression, the higher octane fuels were leaving deposits in the engines. This was addressed through an ECU upgrade. Now, using the logic being put forth here, one should only use 91...NOT 92, 92, 93, and, God forbid,....94 octane. Obviously this is ridiculous. ALL manufacturers of the past 10-15 years provide a wide margin of operational lattitude with fuels. Not all Pumps that say 91 are spot on 91. I miss the old Sunoco pumps where you could actually blend the octane grade you wanted at the pump. Also, the way fuel is distributed in the US, you have no gurantee that you are even getting the actual brand of gasoline you are paying for. Just do what you think is best for you. regardless of what you choose, you will not harm your engine with any commercially available gasoline in the US.
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Old May 10, 2011 | 09:42 AM
  #112  
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Using a higher grade then recommended/required is also very well harmful for the engine (leaves deposits, engine can't burn it properly, etc.).

Best to do is do what the manufacturer requires.
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Old May 10, 2011 | 10:06 AM
  #113  
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I'm not sure I agree K-A. The manual for my Porsche says minimum of 91 octane. I would think the same applies to MB. They have much higher octane fuel in Europe and these cars are designed for it.
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Old May 10, 2011 | 11:07 AM
  #114  
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Originally Posted by petee1997
I'm not sure I agree K-A. The manual for my Porsche says minimum of 91 octane. I would think the same applies to MB. They have much higher octane fuel in Europe and these cars are designed for it.
They also have much lower octane fuels around the rest of the world, and, these cars are designed for that too.
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Old May 10, 2011 | 06:33 PM
  #115  
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Ok, now I've heard that higher octane fuel caused deposits, and that lower octane fuel can cause deposits, all from the same side. Which is it?

For those telling me to read the thread, I suggest you take your own advice. I have not argued that there would not be a loss of performance. I've said I don't believe that 87 octane would [B]cause damage [B] to the engine. If it did, you'd see MB cars all over the place with engine damage because people who don't know better will fill them with 87, along with some trying to save money.

I haven't run mine on 87 yet, other than what my spouse has put in the tank, so I can't comment other than to say what I believe.

I'm still waiting to hear from someone who has actual, verifiable, engine damage to the car. I'll even take someone who has seen it, even if not their own car.

I think MB engineers and marketing folks are all too smart to create a product that can actually suffer damage from 87 octane fuel in the United States.

TJdehya, I am truly heartbroken to be on your ignore list. I haven't been able to concentrate all day, and I certainly will lose sleep tonight. I hope that makes you feel as good as putting 91 octane into your gas tank.
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Old May 10, 2011 | 06:38 PM
  #116  
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Some things to ponder: As gas prices go up, many people switch their gas to the lower grade to save money. Gas looses anywhere from 1 to 3 octanes a month depending on additives and stabilizers and the longer it sits, the more contaminents that get into the pump tank. Ever wonder how long that 91 has been sitting? Good chance the 91 may just be that 87, 88, or 89 that will damage your motor. Another thing, you ever think when a tanker has a few hundred gallons of 87 left in the tank, they dump it before they deliver the 91 octane order? You guys think orders don't get confused in the fuel industry? Ever hear of tanker drivers putting deisel in unleaded tanks? We know about those but bet we never hear about the 87 going in the 91 tank, and why is that? You think MB could afford to take these chances that no mistakes will ever be made in the fuel industry and when it says 91, that's exactly what it is? As the saying goes, "what you don't know won't hurt you" or your car.
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Old May 10, 2011 | 06:46 PM
  #117  
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Originally Posted by RNBRAD
Some things to ponder: As gas prices go up, many people switch their gas to the lower grade to save money. Gas looses anywhere from 1 to 3 octanes a month depending on additives and stabilizers and the longer it sits, the more contaminents that get into the pump tank. Ever wonder how long that 91 has been sitting? Good chance the 91 may just be that 87, 88, or 89 that will damage your motor. Another thing, you ever think when a tanker has a few hundred gallons of 87 left in the tank, they dump it before they deliver the 91 octane order? You guys think orders don't get confused in the fuel industry? Ever hear of tanker drivers putting deisel in unleaded tanks? We know about those but bet we never hear about the 87 going in the 91 tank, and why is that? You think MB could afford to take these chances that no mistakes will ever be made in the fuel industry and when it says 91, that's exactly what it is? As the saying goes, "what you don't know won't hurt you" or your car.
Bingo. And how many people let their baby sit in the garage all winter, letting their premium fuel lose octane? I'd like to hear exactly what this damage would look like from a Mercedes engineer.
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Old May 10, 2011 | 08:55 PM
  #118  
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Originally Posted by dmwil
Ok, now I've heard that higher octane fuel caused deposits, and that lower octane fuel can cause deposits, all from the same side. Which is it?

For those telling me to read the thread, I suggest you take your own advice. I have not argued that there would not be a loss of performance. I've said I don't believe that 87 octane would [B]cause damage [B] to the engine. If it did, you'd see MB cars all over the place with engine damage because people who don't know better will fill them with 87, along with some trying to save money.

I haven't run mine on 87 yet, other than what my spouse has put in the tank, so I can't comment other than to say what I believe.

I'm still waiting to hear from someone who has actual, verifiable, engine damage to the car. I'll even take someone who has seen it, even if not their own car.

I think MB engineers and marketing folks are all too smart to create a product that can actually suffer damage from 87 octane fuel in the United States.

TJdehya, I am truly heartbroken to be on your ignore list. I haven't been able to concentrate all day, and I certainly will lose sleep tonight. I hope that makes you feel as good as putting 91 octane into your gas tank.
You are unlikely to find a person that has verifiable damage to their engine attributed to octane ratings, so you needn't ask anymore. The electronics, variable valve timing, knock sensors, and the like allow Virtually all modern fuel injected engines to run on a broad range of octane ratings. That said, most manufacturers tune their engines for optimum performance with a specific grade of fuel and, hence, will only guarantee performance with fuels meeting the specification. Poorer performance (and how much poorer is variable) is the only potential downside. Keep in mind that at higher elevations, octane ratings are generally lower. I am pretty sure that MB planned on selling cars in Denver. Now, why would someone not want to have their engine running optimally? This I do not understand. But, to say they are damaging their engines is quite a leap.
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Old May 10, 2011 | 09:17 PM
  #119  
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Originally Posted by dmwil
Ok, now I've heard that higher octane fuel caused deposits, and that lower octane fuel can cause deposits, all from the same side. Which is it?
Um.... It depends on what your motor requires.

How can we make this easier? Lol: If a motor is required to burn 91+, then lower octane will engage the knock sensors and protective measures to compensate for the lower octane gas, which means that the gas would harm the motor, were it not for the electronics compensating. The motor will not operate at its peak level, and performance AND Gas mileage will suffer.

If you use higher Octane than what the motor requires, you are pi$$ing away money, and your motor isn't going to burn the gas properly, leaving deposits, and hurting longevity and performance/gas mileage.

Key words are also "recommend", and "require".
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Old May 10, 2011 | 09:25 PM
  #120  
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Originally Posted by K-A
Um.... It depends on what your motor requires.

How can we make this easier? Lol: If a motor is required to burn 91+, then lower octane will engage the knock sensors and protective measures to compensate for the lower octane gas, which means that the gas would harm the motor, were it not for the electronics compensating. The motor will not operate at its peak level, and performance AND Gas mileage will suffer.

If you use higher Octane than what the motor requires, you are pi$$ing away money, and your motor isn't going to burn the gas properly, leaving deposits, and hurting longevity and performance/gas mileage.

Key words are also "recommend", and "require".
I don't disagree with anything you said there. I interpret it as supporting my point that 87 octane won't cause damage.
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Old May 10, 2011 | 09:55 PM
  #121  
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Yes, it probably won't (I doubt it), but if someone were to go like 150K miles or so, I'm wondering if it would have any wear-down effects by then, or worse.

Fact is, to me, the fact that it forces the electronics to compensate for it (i.e, the fact that it would cause catastrophic damage if it weren't for the nannies) is enough to stick with 91.

The argument about 91 sitting and losing Octane is a good one, but it's something that we'll never really know, so best bet is to just do what you feel/know is right. Also, that makes a good argument to go to a populated and volume-heavy Gas Station.
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Old May 11, 2011 | 08:18 AM
  #122  
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How about this...

Stop arguing this point altogether and face the simple point:

When you buy MB's (or any car for that matter) they all have recommended gas octane, oil, and maintenance schedules. If you cannot abide by what is recommended whether you cannot afford it, or just don't want to...don't buy the car. In the case that you already bought it (which says something about your thought process) then sell the car to someone that will take proper care of it.

Who cares if engine damage is caused or not or showing proof? Every-time gas goes up, I see these bantered arguments about MB's and someone trying to skirt around the required gas posted for the car...every damn time. Buy the right damn gas for your car, whatever car you have. That's it, no debate. Why even chance it on your car? Too expensive of a gamble..IMO.

From Faqs.org:

6.16 What happens if I use the wrong octane fuel?

If you use a fuel with an octane rating below the requirement of the engine,
the management system may move the engine settings into an area of less
efficient combustion, resulting in reduced power and reduced fuel economy.
You will be losing both money and driveability. If you use a fuel with an
octane rating higher than what the engine can use, you are just wasting
money by paying for octane that you can not utilise. The additive packages
are matched to the engines using the fuel, for example intake valve deposit
control additive concentrations may be increased in the premium octane grade.
If your vehicle does not have a knock sensor, then using a fuel with an
octane rating significantly below the octane requirement of the engine means
that the little men with hammers will gleefully pummel your engine to pieces.

You should initially be guided by the vehicle manufacturer's recommendations,
however you can experiment, as the variations in vehicle tolerances can
mean that Octane Number Requirement for a given vehicle model can range
over 6 Octane Numbers. Caution should be used, and remember to compensate
if the conditions change, such as carrying more people or driving in
different ambient conditions. You can often reduce the octane of the fuel
you use in winter because the temperature decrease and possible humidity
changes may significantly reduce the octane requirement of the engine.

Use the octane that provides cost-effective driveability and performance,
using anything more is waste of money, and anything less could result in
an unscheduled, expensive visit to your mechanic.
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Old May 11, 2011 | 09:21 AM
  #123  
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Only a degreed (BS at least) automotive engineer can answer this question. And then only one who has actually studied and had experience with using lower octane fuels in engines designed for higher octanes.
READ the Operator's Manual. M-B will jump on any reason they can to disallow a warranty repair.
For me, 91 octane or "nothing at all."
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Old May 11, 2011 | 09:29 AM
  #124  
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Mine is 12 years old. I'm not worried about warranty. However, I wholeheartedly agree with your advice for those whose cars are covered.
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Old May 11, 2011 | 09:37 AM
  #125  
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6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


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Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


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Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


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8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


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Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


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Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


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Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


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5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


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Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


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10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


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