GC 0W30 vs. M1 0W40

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Dunno, everyone is hunting after the German Castrol 0W30, but if you look at the specs of M1 0W40 it has the same manufacturer approvals and ACEA classifications.......its a little more viscous (80/14.3 vs.68.5/12.1) but it seems that the Mobil 1 0W40, which you can get at our local WalMart would fit the bill just as well
 

Al

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M-1 has a tendency to shear down. I'd go with Delvac instead. But if the choice is between the GC and 0W-40 Mobil 1- I'd be tempted to go with the GC even with the limited number of UOA's. That's just me though.
 
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The primary advantage that GC 0w30 seems to have over M1 0w40 (at least in some applications) is that it's more shear stable. Mobil 1 0w40 (by design) usually shears down to a high 30 wt in most applications. It's true that M1 0w40 has pretty much the same ACEA ratings and OEM approvals as the GC. However, it also has the coveted MB 229.5 rating, which is the toughest and longest drain OEM spec in Europe. GC 0w30 is rated 229.3, the second toughest.
 

Alex D

Thread starter
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This shear thingy baffels me because as you mention G-Man, M1 0W40 does have apporval for the long drain interval cycle by Mercedes and VW, even in Diesel engines !!! I wonder how that can be if it shears down so quickly ?? [Confused]
quote:
Originally posted by G-Man II: The primary advantage that GC 0w30 seems to have over M1 0w40 (at least in some applications) is that it's more shear stable. Mobil 1 0w40 (by design) usually shears down to a high 30 wt in most applications. It's true that M1 0w40 has pretty much the same ACEA ratings and OEM approvals as the GC. However, it also has the coveted MB 229.5 rating, which is the toughest and longest drain OEM spec in Europe. GC 0w30 is rated 229.3, the second toughest.
 
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quote:
Originally posted by Alex D: This shear thingy baffels me because as you mention G-Man, M1 0W40 does have apporval for the long drain interval cycle by Mercedes and VW, even in Diesel engines !!! I wonder how that can be if it shears down so quickly ??
Mobil has DESIGNED this oil to shear. The 229.5 spec has a pretty tough fuel economy requirement, as do most OEM ED specs in Europe. If Mobil designed this oil to be completely shear stable, it would meet the fuel economy spec initially, but as the oil ages over the course of 20,000 to 25,000 miles, it would thicken from oxidation and by the end of its operational life would no longer be able to. By designing the oil to intially thin a bit, the thickening that will occur with age is offset. Hence, over its operational life, Mobil 1 will begin and end at roughly the same viscosity. The "dip" in viscosity comes in between. Many of us have problems with designing an oil like this, much prefering an oil that will pretty much maintain its original viscosity throughout its operational life. Nevertheless, DaimlerChrysler, Porsche, and Aston Martin must be comfortable with this approach, for they all put Mobil 1 0w40 in their engines at the factory.
 
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I want to introduce an item for thought...I'm REALLY NOT trying to accuse, but just get people to think about something. When I first saw the Mercedes approval listings 22X.X - 229.5, I thought those are the benchmarks to shoot for. But as I became smarter through this board about the performance of various oils and considered the Mercedes listings, I began to have some concerns as to what drives the lists. There could be a number of coincidences or logical explanations but I've noticed with regard to the 229.5 list: (1) that the first oil that was 229.5 approved was a German oil (Fuchs); it appears it is a great oil in its own right, but nonetheless it is a German oil; (2) that there is German oil (Aral, Fuchs), French Oil (Elf, Total), Italian oil (Agip), a global oil with whom Mercedes has had a racing relationship (Mobil 1), a global oil with a very strong presence in Germany (Shell), and an American Oil (Quaker State) among others (IOW most all the "bases" are covered); and (3) Castrol, which is NOT on the list is closely associated with rival BMW. I can't help but wonder if $$$$, influence and politics are part of the mix as well as performance. The whole point of this is, if you are going to say, "Well M1 0W40 has to be good, it is a 229.5 oil," maybe that is a solid performance indicator and maybe it's not. It could very well be that this is a straightforward "do the tests and use the results" or "read 'em and weep" process...but, until we get someone on the board who knows how it happens, I would not arbitrarily say, "Well this oil has to be good," or "Oil A is better than Oil B, because its on list 22X.X." I'd be careful at jumping to those conclusions. Every one of these oils may indeed be at the top of the tribologists art...just consider all the possibilities before reaching that conclusion. [ October 06, 2003, 08:56 PM: Message edited by: pscholte ]
 
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quote:
I can't help but wonder if $$$$, influence and politics are part of the mix as well as performance.
Absolutely. That has a lot to do with it. I still think when you look at $/Performance, Mobil 1 is top notch. Specialty brands like Redline, Amsoil and Shell Ultra Helix are all as good or better then OTC M1, but it's also more money. The thing you have to realize is that if Porche, Mercedez, GM and Aston Martin all aprove of Mobil 1, you can bet it is good oil.
 
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pscholte, Geez...I can appreciate the comments but don't you think you could have cut the words in half? [Razz] You guys from Colorado don't have enough O2 in the air and no doubt feel the need to say things twice...and twice as fast before that feeling of lightheadedness sets in. [Big Grin] Actually, I've been looking at the backs of M1 and GC and I have the same questions that other oil geeks do. My first reaction is that both oils are more similar than disimilar but I'd tend to think that for my use, GC would be better because we're only swinging 30 points and not 40. I'd love to chat more but I've got to fill out my Absentee Ballot while eating sushi. It's what we do... [ October 06, 2003, 09:50 PM: Message edited by: Flashlightboy ]
 
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Sure, I could cut the words in half but then if I did that I would have only half as many words and if I had only half as many words I probably would only get to say half of what I wanted to say but that would mean that my thoughts would be incomplete and if they were incomplete then.......
 
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quote:
Originally posted by pscholte: Sure, I could cut the words in half but then if I did that I would have only half as many words and if I had only half as many words I probably would only get to say half of what I wanted to say but that would mean that my thoughts would be incomplete and if they were incomplete then.......
Pscholte, your just mad Mobil1 0w-40 meets a higher spec. than your beloved GC....just kiddin', just kiddin' [Big Grin] With that said, I think GC is a great oil that combines exceptional qualities in one product: Low Pour Point Oil Flowing Quick On Startup Shear Stable Synthetic base stock - Low VII amount Thick operational temperture...better protection, less reliance upon additives. Great additive package Extended drain capable Blah, blah, blah... Guess what though...with the exception of being extremely shear stable, Mobil1 0w-40 has all these same qualities, and can be purchased all over the place. Just playing devils advocate...
 
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Nah, if you look at these numbers I ran a few weeks ago, you'll see the reality of all the misinformation being spread around. If you even look at these recalculated numbers, which I ran the next day to "compensate" for EC's bad report, you'll see how well these two oils compare. As a matter of fact, EC appears to be almost as good as M1 at retaining its viscosity ...
 
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I really like the M1 0w40 I have used the tri-syn SG and the new super syn, Lowered consumption over m1 10w-30 I do remember hearing a lot that it shears, then thickens back up... G-man explanation sounds about right!
 
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Fleming Island, FL
quote:
Originally posted by G-Man II: The primary advantage that GC 0w30 seems to have over M1 0w40 (at least in some applications) is that it's more shear stable. Mobil 1 0w40 (by design) usually shears down to a high 30 wt in most applications.
I'm a bit confused. If M1 0W40 shears down to a 0W30, how is that, then, inferior to GC 0W30? Don't the two oils become essentially the same, or at least similar enough not to worry about? - Arved
 

Patman

Staff member
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Oakville, Ontario
quote:
Originally posted by Arved:
quote:
Originally posted by G-Man II: The primary advantage that GC 0w30 seems to have over M1 0w40 (at least in some applications) is that it's more shear stable. Mobil 1 0w40 (by design) usually shears down to a high 30 wt in most applications.
I'm a bit confused. If M1 0W40 shears down to a 0W30, how is that, then, inferior to GC 0W30? Don't the two oils become essentially the same, or at least similar enough not to worry about? - Arved

If you had the choice between two oils, one which starts at 14cst and then finishes at 11cst, in a 6000 mile interval, then the other which starts at 12cst, but finishes at 11cst in the same interval, which of the two do you think is going to leave the engine cleaner? That would be my concern. So even though they both finish up at the same viscosity, if the 0w40 is thinning out more, it's not going to keep things as clean in the long run.
 
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Greenville, SC
quote:
Originally posted by Alex D: Dunno, everyone is hunting after the German Castrol 0W30, but if you look at the specs of M1 0W40 it has the same manufacturer approvals and ACEA classifications.......its a little more viscous (80/14.3 vs.68.5/12.1) but it seems that the Mobil 1 0W40, which you can get at our local WalMart would fit the bill just as well
I looked for Mobil 1 0W40 for a long time and I couldn't find it. I really don't think it's an easy find for some of us. When did I first spot Mobil 1 0W40? I saw it at AutoZone when I first found GC.
 
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Correct me if I'm wrong Patman, but doesn't the M1 0w-40 have more esters in it than their "regular" formula? Wouldn't this help cover the 40 point spread and help with cleaning? And considering the GC is heavily fortified with esters too (we assume) we are comparing to oils that are very close in performance. Or maybe I'm wrong.
 
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quote:
Originally posted by Patman:
quote:
Originally posted by Arved:
quote:
Originally posted by G-Man II: The primary advantage that GC 0w30 seems to have over M1 0w40 (at least in some applications) is that it's more shear stable. Mobil 1 0w40 (by design) usually shears down to a high 30 wt in most applications.
I'm a bit confused. If M1 0W40 shears down to a 0W30, how is that, then, inferior to GC 0W30? Don't the two oils become essentially the same, or at least similar enough not to worry about? - Arved

If you had the choice between two oils, one which starts at 14cst and then finishes at 11cst, in a 6000 mile interval, then the other which starts at 12cst, but finishes at 11cst in the same interval, which of the two do you think is going to leave the engine cleaner? That would be my concern. So even though they both finish up at the same viscosity, if the 0w40 is thinning out more, it's not going to keep things as clean in the long run.

Agree totally, Pat
 
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