Winter oil recommendation for BMW w/ M54 inline 6

[kschachn]

Originally Posted By: OldEuroCarLover

What if it's an oil that has a certification like BMW LL-01 that, presumably, means the oil should stay within spec for the allotted OCI? That's what I meant when I said all other aspects being equal. What if it's a 0w30 and a 5w30 with the same certification? From what I understand about all of this so far, the Castrol Edge 0w40, with the LL-01 certification, should be much better overall than any 5w30 with the same certification. Thicker at operating temp and able to withstand sustained high RPMs, and thinner at winter temps for cold starts. I guess I'm trying to wrap my head around BMW's reason for recommending 5w30 when they could easily recommend 0w40.

In the case of LL-01 BMW's requirement is an oil that meets that specification and the grade becomes irrelevant for all practical purposes. You're obsessing focusing on the wrong thing, as long as the oil meets the minimum HTHS it will be functionally equivalent.

 

[RooflessVW]

Originally Posted By: OldEuroCarLover

Originally Posted By: Quattro Pete

Originally Posted By: OldEuroCarLover

Am I correct to assume that--all other aspects of the oil being equal, including price--a 0w30 is always preferable to a 5w30?

No, you can't just assume that. The 0w30 could have more VIIs in it and be less shear stable.

What if it's an oil that has a certification like BMW LL-01 that, presumably, means the oil should stay within spec for the allotted OCI? That's what I meant when I said all other aspects being equal. What if it's a 0w30 and a 5w30 with the same certification? From what I understand about all of this so far, the Castrol Edge 0w40, with the LL-01 certification, should be much better overall than any 5w30 with the same certification. Thicker at operating temp and able to withstand sustained high RPMs, and thinner at winter temps for cold starts. I guess I'm trying to wrap my head around BMW's reason for recommending 5w30 when they could easily recommend 0w40.

The four "grades" are all within spitting when they carry LL01. LL01 0W-30, 5W-30, 0W-40, and 5W-40 all look VERY similar with regards to cold viscosity, hot viscosity, and film strength. The "grade" is not important or relevant in this case. The certification is.

 

[OldEuroCarLover]

This would, it seems, be a very simple discussion on an oil forum. Winter viscosity and operating temp viscosity. But it seems like it's not. So, what I'm hearing, its that an LL-01 oil is the same, basically, regardless of stated viscosity? It seems like the certification is more important than anything else on the bottle, in this case or any other. Does this apply to most/all manufacturer specs, or is LL-01 special? Due to the fact that we're not talking about just BMW branded LL-01 5w30, but many oils that happen to carry the certification, it would seem that most of the stated weights--the big numbers on the front of the bottles--are not very important. As far as obsessing over this, I'm not. I just want to know what the situation with regard to oil viscosity at operating temp and cold start during low ambient temps. This is an oil forum. It's basically a web page for long, drawn out, obsessive discussions about car stuff. I'm not just after a specific recommendation for this car anymore, but a thorough understanding of this area for the future.

Originally Posted By: rooflessVW

The four "grades" are all within spitting when they carry LL01. LL01 0W-30, 5W-30, 0W-40, and 5W-40 all look VERY similar with regards to cold viscosity, hot viscosity, and film strength. The "grade" is not important or relevant in this case. The certification is.

So, based on this, is it fair to say that a 0w40 is the "best" of the three? Performing well under high revs at operating temp, and flowing the best during cold start? Even assuming it's negligible to say it's the best, is it still at least slightly better than the other weights? I'm not trying to bother you guys. I genuinely want to understand this.

 

[jayg]

Originally Posted By: OldEuroCarLover

So, based on this, is it fair to say that a 0w40 is the "best" of the three? Performing well under high revs at operating temp, and flowing the best during cold start? Even assuming it's negligible to say it's the best, is it still at least slightly better than the other weights? I'm not trying to bother you guys. I genuinely want to understand this.

It would depend on which 0w40 compared to specifics oils of the grade. Depending on the application, it may make more sense in the big picture to go with a different oil. I would narrow it down to three oils from your research and then get opinions on here on which one to choose and the poster can give you the specific reasons why.

 

[RooflessVW]

To me, Castrol 0W-40 is "best" because it meets LL01 AND all of the other major European specs, and is the most WIDELY available. You can pick up a quart without searching no matter where you are, and it is $22 for a 5 quart jug. It is made in Germany, and is a "true" synthetic, if that matters to you. Also, FWIW, my 4.2 is quieter on the Castrol 0W-40. Seriously though, when you compare all the PDS data side by side, they are all about the same viscosity cold, and hot. The HTHS values are more or less the same. Just pick one and it'll do as well as any of the others. MAG 1 makes an inexpensive LL01 oil as well.

 

[OldEuroCarLover]

Originally Posted By: jayg

Originally Posted By: OldEuroCarLover

So, based on this, is it fair to say that a 0w40 is the "best" of the three? Performing well under high revs at operating temp, and flowing the best during cold start? Even assuming it's negligible to say it's the best, is it still at least slightly better than the other weights? I'm not trying to bother you guys. I genuinely want to understand this.

It would depend on which 0w40 compared to specifics oils of the grade. Depending on the application, it may make more sense in the big picture to go with a different oil. I would narrow it down to three oils from your research and then get opinions on here on which one to choose and the poster can give you the specific reasons why.

I accidentally said "three" because I was responding to this post and skimmed it so quickly that I missed that four were listed, including 5w40:

Originally Posted By: rooflessVW

LL01 0W-30, 5W-30, 0W-40, and 5W-40 all look VERY similar

I wasn't referring to any specific oils. Just whether 0w40 would technically be the "best" all around oil out of any LL-01 oils, considering the fact that they all meet the same certification. (It would be great if we actually knew what that certification specifies.)

Originally Posted By: rooflessVW

To me, Castrol 0W-40 is "best" because it meets LL01 AND all of the other major European specs, and is the most WIDELY available. You can pick up a quart without searching no matter where you are, and it is $22 for a 5 quart jug. It is made in Germany, and is a "true" synthetic, if that matters to you. Also, FWIW, my 4.2 is quieter on the Castrol 0W-40. Seriously though, when you compare all the PDS data side by side, they are all about the same viscosity cold, and hot. The HTHS values are more or less the same. Just pick one and it'll do as well as any of the others. MAG 1 makes an inexpensive LL01 oil as well.

The bolded text is why I agree that Edge 0w40 seems to be the best oil to put in any BMW that requires LL-01. I guess my question is whether that tiny bit of difference in viscosity makes the 0w40 just a tiny bit better than the others, or if there are some more complex reasons that they're all completely the same in the end. Does the 0w40 end up behaving like a 5w30 after a few thousand miles? Is there any reason at all to pay for BMW's oil? Castrol Edge 0w40 almost seems too good to be true. (Not that I believe that to be the case. From what I've read, it's a great oil.) I'm definitely, at this point, using it for the next oil change. I just want to know a bit more about all of this.