Is Mobil 1 0w-40 too thin?

[Japanese]

May we get info on the current formula or at least PAO of this oil because I read already on a few places that Mobil changed the FS )W-40 formula after 2022-2023 and it's not that robust as before.

Here is what the oil formula was in 2021. Can we compare with the current one?
https://bobistheoilguy.com/forums/threads/updated-m1-fs-0w-40-more-pao.347965/

Thank you.

 

[kschachn]

May we get info on the current formula or at least PAO of this oil because I read already on a few places that Mobil changed the FS )W-40 formula after 2022-2023 and it's not that robust as before.

Here is what the oil formula was in 2021. Can we compare with the current one?
https://bobistheoilguy.com/forums/threads/updated-m1-fs-0w-40-more-pao.347965/

Thank you.

For one thing, that's not the formula. And how are you able to predict future performance from an SDS?

 

[CleanSump]

You can't bake cookies from an SDS. All it is going to tell you is it has flower, proprietary flavoring, don't let it spill in a lake, and wear protective gear if it's on fire.

 

[johnmyster]

May we get info on the current formula or at least PAO of this oil because I read already on a few places that Mobil changed the FS )W-40 formula after 2022-2023 and it's not that robust as before.

Here is what the oil formula was in 2021. Can we compare with the current one?
https://bobistheoilguy.com/forums/threads/updated-m1-fs-0w-40-more-pao.347965/

Thank you.

"Robust."

I'm looking forward to the API's new rating system where they have a rating for "Robustness" and "Stoutness" included on the starburst. It's probably the most helpful quantities shown on the lubrizol spider charts. Right up there with finger slipperyness.

 

[Japanese]

For one thing, that's not the formula. And how are you able to predict future performance from an SDS?

But what was the change and why? Is it the API SQ requirement over SP, but in '22 and '23 SP was the latest?
Also, is that change visible in VOA?

 

[kschachn]

But what was the change and why? Is it the API SQ requirement over SP, but in '22 and '23 SP was the latest?
Also, is that change visible in VOA?

Who knows. I was asking you since you said it wasn’t as robust as before. I figured you had a technical reason for making that claim.

And who knows on the VOA. Hard to tell a lot about robustness from decomposed compounds and only the mostly metallic elements. At least it is for me.

 

[GenSan]

Mobil 1 FS Euro 0w-40 sheared down to a 30 weight oil in my 2025 Nissan Armada Pro-4x with a 3.5L V6 twin-turbo. Other than that wear metals were below universal averages and TBN was 8.2.

 

[GW.]

But what was the change and why? Is it the API SQ requirement over SP, but in '22 and '23 SP was the latest?
Also, is that change visible in VOA?

I’m no expert so take this with a grain of salt. When FS 0W-40 and ESP 5W-30 went SP and BMW Longlife is when the formula changed away from the rest of the ESP line. No more ester. Many here have said BMW limits virgin oxidation. As far as it being less robust I don’t know, just different.

If you liked the old formula buy the ESP 0W-40.

 

[kschachn]

Mobil 1 FS Euro 0w-40 sheared down to a 30 weight oil in my 2025 Nissan Armada Pro-4x with a 3.5L V6 twin-turbo. Other than that wear metals were below universal averages and TBN was 8.2.

What was the fuel dilution?

 

[Japanese]

Who knows. I was asking you since you said it wasn’t as robust as before. I figured you had a technical reason for making that claim.

I read a few people on here say that. That's why I decide to ask.

 

[GenSan]

What was the fuel dilution?

There was no fuel detected and flashpoint was normal.

 

[kschachn]

There was no fuel detected and flashpoint was normal.

Who was the analysis company?

 

[scrllock]

I’m no expert so take this with a grain of salt. When FS 0W-40 and ESP 5W-30 went SP and BMW Longlife is when the formula changed away from the rest of the ESP line. No more ester. Many here have said BMW limits virgin oxidation. As far as it being less robust I don’t know, just different.

If you liked the old formula buy the ESP 0W-40.

ESP 0w40 no longer exists. Supercar is, like ESP X4, a GTL/PAO/Ester blend, and I believe Supercar is also mid-SAPS. If you liked the old Mobil 1 Full Synthetic 0w40, they don't offer a product quite like it at this point. I don't think anyone has conclusive evidence that the current FS is not robust.

 

[johnmyster]

Mobil 1 FS Euro 0w-40 sheared down to a 30 weight oil in my 2025 Nissan Armada Pro-4x with a 3.5L V6 twin-turbo. Other than that wear metals were below universal averages and TBN was 8.2.

Everybody wants to act like a change of 0.3 is a big deal. It isn't. It was a thin 40, it's now a thick 30. It's still a great oil and more than sufficient viscosity/HTHS for use in cars that didn't even call for a 40 in the first place...such as your nissan.

Oh no, only 12.1 cSt after 5000 miles. Oil is falling apart!

robust.

"Robust"

 

[RedEnsign]

What oil doesn't shear down a grade? My Audi S5 took motul 8100 xcess (sn) from 14.2 to 12.5cst in 5500km. (with a little fuel dilution)

According to the website, Mobil 1 Full Synthetic 0w40 starts at 13.8cst now. Castrol 13.5. Motul 13.5. PPE/QS at 13.0 These are the SP formulas. Mobil starts higher, and Pennzoil Platinum Euro usually ends the lower. If any oil deserves to be called a 30 grade, its the gtl based 40's.
How does this disinformation happen? That old formula might have had a lot of VII, started out lower, and maybe people beat on harder than other oils, i don't know.

Have any recent used oil analysis confirmed it shearing out of grade too quickly?

 

[kschachn]

What oil doesn't shear down a grade? My Audi S5 took motul 8100 xcess (sn) from 14.2 to 12.5cst in 5500km. (with a little fuel dilution)

According to the website, Mobil 1 Full Synthetic 0w40 starts at 13.8cst now. Castrol 13.5. Motul 13.5. PPE/QS at 13.0 These are the SP formulas. Mobil starts higher, and Pennzoil Platinum Euro usually ends the lower. If any oil deserves to be called a 30 grade, its the gtl based 40's.
How does this disinformation happen? That old formula might have had a lot of VII, started out lower, and maybe people beat on harder than other oils, i don't know.

Have any recent used oil analysis confirmed it shearing out of grade too quickly?

An oil without VII (a monograde) will not shear.

Do you have evidence that your engine has a problem with mechanical shear of the VII? Most viscosity deviations we see here are due to fuel dilution. Shear is not common.

You say a little fuel dilution. Who performed the analysis? Blackstone is useless in this regard. In fact it’s worse, it’s deceptive.

 

[RedEnsign]

An oil without VII (a monograde) will not shear.

Do you have evidence that your engine has a problem with mechanical shear of the VII? Most viscosity deviations we see here are due to fuel dilution. Shear is not common.

You say a little fuel dilution. Who performed the analysis? Blackstone is useless in this regard. In fact it’s worse, it’s deceptive.

No not Blackstone, oil analyzers. Up to 3% at 5500km. 2.3% after 6500km a little top up from oil consumption, which is needed now unfortunately.

The only evidence I can give to shear, is the engine makes a lot of power, heat, and is driven hard on occasion. Im under the assumption that will test an oils ability to shear, no?

Which common oils, 40 grade, have no VII? From what I've seen, only boutique oils like hpl no VII. Or ones with very heavy pao, as that is very shear resistant.

There's that chart posted every now and then, created by lake speed Jr. showing the shear tests for many oils, as well as straight paos. Mobil 1 and castrol 40 grades both sheared down quite a bit. The paos held steady, but are in the 20-30grade range by nature, yes?

Most used oil analysis I've seen show oils, off the shelf, falling out of grade over time. That can't all be due to fuel dilution?

I'm looking at a forum members post that compares Pennzoil Platinum Euro 5w40 to redline. The Pennzoil Platinum Euro sheared under 11, from 13, in only 4500km. The redline went longer, sheared less but still stayed in grade, over 6500km. Fuel dilution was 1.2%. Many other tests show the same results.

Can you show me any tests that show that oil, or other common oils, that hold completely steady over time? Because I haven't come across any.

 

[edyvw]

No not Blackstone, oil analyzers. Up to 3% at 5500km. 2.3% after 6500km a little top up from oil consumption, which is needed now unfortunately.

The only evidence I can give to shear, is the engine makes a lot of power, heat, and is driven hard on occasion. Im under the assumption that will test an oils ability to shear, no?

Which common oils, 40 grade, have no VII? From what I've seen, only boutique oils like hpl no VII. Or ones with very heavy pao, as that is very shear resistant.

There's that chart posted every now and then, created by lake speed Jr. showing the shear tests for many oils, as well as straight paos. Mobil 1 and castrol 40 grades both sheared down quite a bit. The paos held steady, but are in the 20-30grade range by nature, yes?

Most used oil analysis I've seen show oils, off the shelf, falling out of grade over time. That can't all be due to fuel dilution?

I'm looking at a forum members post that compares Pennzoil Platinum Euro 5w40 to redline. The Pennzoil Platinum Euro sheared under 11, from 13, in only 4500km. The redline went longer, sheared less but still stayed in grade, over 6500km. Fuel dilution was 1.2%. Many other tests show the same results.

Can you show me any tests that show that oil, or other common oils, that hold completely steady over time? Because I haven't come across any.

You have my used oil analysis on various oils. Not sheared at all. I posted numerous time Pennzoil Platinum Euro 5W40 with extensive track time in BMW, 5,000mls OCI. Stayed above 13cst.

 

[kschachn]

No not Blackstone, oil analyzers. Up to 3% at 5500km. 2.3% after 6500km a little top up from oil consumption, which is needed now unfortunately.

The only evidence I can give to shear, is the engine makes a lot of power, heat, and is driven hard on occasion. Im under the assumption that will test an oils ability to shear, no?

Which common oils, 40 grade, have no VII? From what I've seen, only boutique oils like hpl no VII. Or ones with very heavy pao, as that is very shear resistant.

There's that chart posted every now and then, created by lake speed Jr. showing the shear tests for many oils, as well as straight paos. Mobil 1 and castrol 40 grades both sheared down quite a bit. The paos held steady, but are in the 20-30grade range by nature, yes?

Most used oil analysis I've seen show oils, off the shelf, falling out of grade over time. That can't all be due to fuel dilution?

I'm looking at a forum members post that compares Pennzoil Platinum Euro 5w40 to redline. The Pennzoil Platinum Euro sheared under 11, from 13, in only 4500km. The redline went longer, sheared less but still stayed in grade, over 6500km. Fuel dilution was 1.2%. Many other tests show the same results.

Can you show me any tests that show that oil, or other common oils, that hold completely steady over time? Because I haven't come across any.

It’s highly dependent on the engine design whether mechanical shear of the VII is an issue. That and the quality of the VII. So any list is a bit relative since for the vast majority of users this is not a particularly important issue.

Most used oil analysis on here give no clue whatsoever whether shear of the VII is occurring or not. Most are completely useless in this regard.

I just pick an oil that has demonstrated stay-in-grade performance through the approvals it holds. I have zero lost sleep over using ESP or Mobil 1 0W-40 in any engine. Shear, like Noack and flash point and other isolated hot button properties just don’t worry me when I know the oil has VW 504 00 approval, for example.

 

[OVERKILL]

No not Blackstone, oil analyzers. Up to 3% at 5500km. 2.3% after 6500km a little top up from oil consumption, which is needed now unfortunately.

The only evidence I can give to shear, is the engine makes a lot of power, heat, and is driven hard on occasion. Im under the assumption that will test an oils ability to shear, no?

Which common oils, 40 grade, have no VII? From what I've seen, only boutique oils like hpl no VII. Or ones with very heavy pao, as that is very shear resistant.

There's that chart posted every now and then, created by lake speed Jr. showing the shear tests for many oils, as well as straight paos. Mobil 1 and castrol 40 grades both sheared down quite a bit. The paos held steady, but are in the 20-30grade range by nature, yes?

Most used oil analysis I've seen show oils, off the shelf, falling out of grade over time. That can't all be due to fuel dilution?

I'm looking at a forum members post that compares Pennzoil Platinum Euro 5w40 to redline. The Pennzoil Platinum Euro sheared under 11, from 13, in only 4500km. The redline went longer, sheared less but still stayed in grade, over 6500km. Fuel dilution was 1.2%. Many other tests show the same results.

Can you show me any tests that show that oil, or other common oils, that hold completely steady over time? Because I haven't come across any.

Keep in mind that your engine isn't a KRL, it's not going to inflict the same level of abuse on the VII polymers that a test device specifically selected for that purpose is.

The best 0W-40 I've seen, in terms of avoiding visc loss is HPL's, with ~1% fuel, visc moved from 13.9 to 13.2, compared to the Ravenol SSL 0W-40 that dropped down to 12.0 in the same application: