GC 0W30 vs. M1 0W40

[Eiron]

quote:

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Originally posted by Patman:
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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I don't understand why you guys continue with this type of misinformation & number "enhancement"? Nobody's trying to discredit EC's abilities, & yet M1 gets continually slammed for some mythic "thinning" which has been shown to be less than what Castrol's "best" N.A. oil shows!

So are we now saying that 3MP's study, which is using percentages as its basis for tracking the oil's condition, is using the wrong method? Why is percentages the "correct" method for his study, but grade is always cited for this false argument?

[ October 07, 2003, 01:18 PM: Message edited by: Eiron ]

 

[Patman]

quote:

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Originally posted by Eiron:

quote:

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Originally posted by Patman:
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.

---

I don't understand why you guys continue with this type of misinformation & number "enhancement"? Nobody's trying to discredit EC's abilities, & yet M1 gets continually slammed for some mythic "thinning" which has been shown to be less than what Castrol's "best" N.A. oil shows!

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How am I enhancing the numbers? My sister's very first run with GC 0w30 showed that it's final viscosity after 5500 miles was 11.5, and like I mentioned, this is with a tiny bit of Mobil 1 5w30 mixed in with it, so that probably lowered the viscosity by 0.1 or 0.2. But even if it didn't, going from 12.2 down to 11.5 in 5500 miles is not as bad as some of the shearing we've seen M1 0w40 do on here.

My official prediction is that after 3100 miles in my own car, the final viscosity of GC 0w30 will still be in the 11.8 to 12.0 range, from it's starting point of 12.2. To me, that's pretty darn good. And I'm going to be doing 6200 mile intervals from this point on, and expect it to finish up at about 11.5cst.

 

[Arved]

quote:

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Originally posted by Patman:
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.

---

I dunno. You've only told me about the viscosity change, and if they both settle down to 11cst, then they're equivalent.

If the long-chain hydrocarbons that are causing the 0W40 oil to start out with a higher viscosity are, in fact, shearing into shorter chain molecules, then I'd expect both oils to be equally clean. If, on the other hand, the long-chain molecules are falling out of solution and depositing themselves on the side of the engine, leaving only the shorter-chain molecules, then, yes, I could see where you wouldn't like the 0W40 oil.

However, in that last scheme, the viscosity isn't shearing down, as you stated up top. You're now claiming the viscosity is changing due to precipitation of the long-chain hydrocarbons.

- Arved

 

[quadrun1]

I don't think the hydrocarbons are precipitating. As was stated earlier, Mobil 1 designed the 0W-40 to thin initially, and then thicken later, on purpose.

M1 0W-40 cleaned varnish from my the dipstick of my brother's Mitsubishi which used to run Valvoline dino oil... I'm sure 0W-40 keeps an engine just as clean as the rest of the Mobil 1 product line.

In my unscientific "BMW oil cap" test, both M1 0W-40 and GC 0W-30 are keeping the undersides of the BMW oil caps clean (but only about 2,000 miles on each so far; I'm running them both to 10K).

The BMW 5W-30 synth oil which these cars used to run left behind a brownish deposit.

The GC seems to "cling" a little more; the oil cap of the car running GC seems a little "wetter", for whatever that's worth.

Jason

 

[Eiron]

quote:

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Originally posted by Arved:
I dunno. You've only told me about the viscosity change, and if they both settle down to 11cst, then they're equivalent.

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See, this is the fallacy. They don't both settle down to to 11cSt.

In the comparison I linked, I figured UOAs for both EC 0W-30 & M1 0W-40 being run for comparable miles during the same weather season. EC fell from a published 12.1cSt to an average of 10.7cSt, while M1 fell from a published 14.3cSt to an average of 12.8cSt. That's an 11.3% drop for EC, & a 10.8% drop for M1.

In the second comparison, I dropped the starting points for both oils to the lowest values reported from member VOAs, which would yield less change in viscosity when looking at the UOAs. This dropped EC to a starting point to 11.8cSt, & the M1 starting point to 13.6cSt. I also threw out the worst (most sheared) example for each oil, which lessened the viscosity change even further. Without surprise, both oils did better. EC now only dropped to an averaged 11.1cSt, & M1 only dropped to an averaged 12.9cSt. That's still a 6% change for EC, while M1 falls 5%.

M1 0W-40 still holds up better than EC 0W-30!!

Yet, you don't see anyone saying, "I'd never use EC 0W-30," do you? This is the crux of the misinformation problem: invalid conclusions drawn from (what I must assume are) biased opinions.

 

[VeeDubb]

I guess the key question for me is, does sludge from shearing occur due to % drops or absolute drops. For example, a minor shearing of a 5w-20 weight oil may lead to a larger drop *percentage wise* then a moderate shear in a 5w-50 oil, but I have a feeling that the moderate shear in the 50 weight will cause more problems. So I'm hoping an expert will chime in here. Should we worry about the absolute drop or the relative drop in viscosity?

 

[quadrun1]

And conversely, why does the BMW 5W-30 Synth leave behind brownish gunk even though its viscosity remains very constant with use?

I don't think viscosity change is always indicative of sludge formation.

 

[WeyounDS9]

quote:

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Originally posted by quadrun1:

I don't think viscosity change is always indicative of sludge formation.

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Of varnish formation.
VII's form varnish not sludge.Sludge is teh result of decomposing base stock.

If its true that GC is a groupV ( whioch we dont know for sure) then I would expedct it to sludge less.

Of course teh Group IV of M10w-40 is also pretty good at avoiding sludging as a group IV.

Fred..

 

[Patman]

Good points everyone. Perhaps we are worried too much about how an oil thins out, and maybe it's internals can still be clean. I should probably take off the valve cover on my wife's engine when I'm done my Royal Purple testing, since this oil has shown itself to thin out quite a bit, so perhaps it's leaving behind some sludge, or perhaps not (4 intervals with it might not be enough to prove anything in this respect though)

I guess once again, the only way to prove anything is to take one engine which has run nothing but 0w40 Mobil 1, and another which has run nothing but 0w30 GC and see how clean they look inside after 150,000 miles. But then again, they'd have to be two identical engines running the same type of driving and climate conditions.

So who knows?

 

[pscholte]

I do, but I'm not telling...

It would destroy the competition between the Mobilites, the Castrolites, the Amsoilites, the Chevronites, the Redline-ites, the Pennzoilites and the Purple-ites(sounds Biblical, doesn't it?).

 

[WeyounDS9]

I am no -ite yet I feel guilty for buying the 0w-30 ...

They only had 2 quarts of M1 0w-40 but ( nearly enough for an oil change in german castrol 0w-30)

Hence I bought it..

Haven't bought a 30 weight in such a long time and now I emotionally feel its too thin, even tho I know its so close to my highly regarded M1 0w-40.

Haven't bought a Castrol product since the mid 90's, .....(we all know why).

Feels kinda weird now to have both a Castrol, a 30 weight oil!

Wait! I better run outside and look for some flying pigs!

Fred..

[ October 07, 2003, 09:07 PM: Message edited by: palmerwmd ]

 

[buster]

I'm fairly certain that the 0w-40 wont sludge. When Mobil developed this they made it a long drain oil so I'm sure it has enough to fight of sludge.

 

[pscholte]

quote:

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Originally posted by palmerwmd:
I am no -ite yet I feel guilty for buying the 0w-30 ...

They only had 2 quarts of M1 0w-40 but ( nearly enough for an oil change in german castrol 0w-30)

Hence I bought it..

Haven't bought a 30 weight in such a long time and now I emotionally feel its too thin, even tho I know its so close to my highly regarded M1 0w-40.

Haven't bought a Castrol product since the mid 90's, .....(we all know why).

Feels kinda weird now to have both a Castrol, a 30 weight oil!

Wait! I better run outside and look for some flying pigs!

Fred..

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Calm down...everything is going to be alright. Change is invevitable and sometimes it is very, very good.

[ October 07, 2003, 09:26 PM: Message edited by: pscholte ]

 

[TSoA]

I've got the ultimate oil, 50/50 mix of GC and M1!!! For the record, sludge issues are appearing in Mercedes here where dino was used for extended intervals and in Europe where these LL oils are "all the rage" for 30,000 miles.

 

[1maniac]

Mercedes Benz was sued over the "dino in USA" mishap. They had to may US Mercedes Benz owners millions of dollars because they never told them to use synthetic oil for the extended drains. HOWEVER, in europe synthetic was mandatory. 30k miles on Dino..

[ October 08, 2003, 12:15 AM: Message edited by: 1maniac ]

 

[pscholte]

quote:

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Originally posted by userfriendly:
Pscholte;
After studying your second last post above, I have determined that you are related to the famous composer W.A. Mozart.

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I try not to spread that around because I don't want people to think I am a name dropper.

 

[sprintman]

I'm not an -ite yet but when I get too the track and put my bash hat on I get 'Redline Fever' as they say so Redline would probably be my choice but NEO certainly intrigues me.

 

[Arved]

quote:

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Originally posted by Eiron:
Originally posted by Arved:
I dunno. You've only told me about the viscosity change, and if they both settle down to 11cst, then they're equivalent.

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See, this is the fallacy. They don't both settle down to to 11cSt.
M1 0W-40 still holds up better than EC 0W-30!!

[/QB][/QUOTE]

Well, it was Patman who stated that "they both shear down to 11cSt." I wasn't willing to argue the point. From a logical standpoint, if the two oils shear down to the same viscosity, then one isn't necessarily better than the other. They've equalized in so far as the viscosity is concerned.

Now, if there are other factors at work, such as the viscosity change being due to precipitation of the long-chain hydrocarbons (tar deposits) instead of shear down, or if the 0W40 oil continued to shear down, then there would be something to complain about. However, with the information as stated, there's no functional difference between the 0W40 and 0W30 oils in question here.

There's either more to the story that isn't being said, or the arguement is false.

Now that you've opened up the possibility that the two oils don't stabalize at equivalant viscosities, the entire concept of comparing these two oils must be questioned.

- Arved

 

[Patman]

quote:

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Well, it was Patman who stated that "they both shear down to 11cSt." I wasn't willing to argue the point. From a logical standpoint, if the two oils shear down to the same viscosity, then one isn't necessarily better than the other. They've equalized in so far as the viscosity is concerned.

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Re-read my post, I said IF they both were to shear down to 11cst, then which would you choose. I didn't state for a fact that both of them do.

 

[TooSlick]

I think in these cases it's important to consider what sort of viscosity index you can achieve simply from the "neat" basestock blend. From the oil analysis data I've seen, the maximum VI from a blended, PAO/Ester synthetic basestock is probably somewhere in the 150-160 range. ANY oil with a VI higher than this is going to use some polymeric thickener - regardless of the SAE viscosity. Even the best of these polymers will shear by 5%-10%, particularly in multivalve and/or turbo engines.

I don't believe it is possible to make a very shear stable 0w-40 or 5w-50, even with a PAO/Ester basestock. I've also seen 5w-40, Group III oils that shear quite a bit. Regardless of the manufacturer, the 10w-30/15w-40/20w-50 grades will be the most stable in terms of viscosity. Witness the relative performance of the M1, 10w-30 vs their 0w-40. The idea that Mobil formulates their 0w-40 to shear is misleading - it's really not something you can prevent.

All things being equal, it IS desirable to minimize or eliminate the use of VI modifiers. As they thermally decompose, it leads to oil consumption and varnish deposits that cause ring and valve lifter sticking. This is precisely why 10w-40 petroleum oils were specifically banned by General Motors some years back. There is a lot of consumer appeal to the 5w-50 "one size fits all" formulations. However in reality, you end up compromising both low and high temp performance compared to a 5w-30 or 20w-50.