Mix Rotella T6 5w40 with rest of Euro Castrol 0w40

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Hi all,

I switched to Rotella T6 but have a rest of Castrol 0w40 Euro formula left. I'm filled up with T6, but can I top up the T6 from time to time with a bit of the 0w40 Castrol?
This is on a BMW e46 M54B30. I am on the central OR coast, so it just gets a bit below freezing a few days in the winter. No really low temps.

Cheers,
fana
 
Maybe reduced optimality if there is some minor additive clash. People do it all the time, mixing a little of other types or brands of oil. I've never heard of any problem with it. I say fine.
 
A word to those running Rotella T6 and other HDEOs in gasoline engines because some loudmouth on BITOG or some forum told you to. Don't. I used to tell this to people all the time; that HDEOs don't belong in gasoline engines, but I've learned a lot more lately as to specifically why that is the case.

Reason 1: Primary ZDDP. What most people just call Zinc, ZDDP is an additive package in oil that is known for anti-wear properties. I'll spare you the science behind ZDDP decomposition tiers and the nature of boundary lubrication, but what you have to realize is that there are 200+ formulations of ZDDP and they are not all equal. They come in two main categories: primary and secondary. Primary ZDDP is used mostly as an antioxidant to fight oxidative thickening in engine oils in high-heat applications, of which there are plenty in diesel engines, and is also geared more for lower friction coefficient. By contrast, gasoline engines either use mostly secondary ZDDP with some primary, or exclusively secondary (which is the case of higher quality oils), and is geared more for tribofilm formulation. Basically, your 1200ppm of Zinc in Rotella T6 is not actually protecting better than 800ppm of Zinc API SN spec synthetic oil and certainly not better than a high secondary ZDDP formulated gasoline engine oil.

Reason 2: Anti-foaming. Also referred to as air release, the oil has to release air pockets generated during friction and movement. Rotella is not very good at this, and that's OK when you are running a Detroit Diesel with a 2100RPM redline or even a 6.7 Powestroke with a 3400RPM redline (where the anti-foaming starts to become a bigger issue), not so much when you're running a Subaru FA20 with a 7400RPM redline. Under extended use, this can eventually aerate the fluid enough to cause catastrophic failure, or at minimum power loss.

Reason 3: Detergents/Dispersants. Diesel engines typically deal more with soot handling and dispersion, so the additive package is designed accordingly. On the other hand, gasoline engine detergent packs are designed more to handle acidity. This discrepancy can also result in reduced performance in gasoline engines as the detergent tries to clean the cylinder walls, which compromises the seal between rings and cylinder walls and reduces compression and efficiency.


Now I'm sure I'll get the classic "I've been using this oil and nothing has blown up yet" rhetoric by people who are too cheap to consider better options like AMSOIL, Driven Racing, Motul, and Schaeffer, but that doesn't mean that the product doesn't have its deficiencies simply because you want it to work. I realize people have a higher tendency to believe information that they agree with regarding a cheaper product than a more expensive one, but unless you already knew everything I presented in this post, you ought to reconsider your lubricant choice in gasoline engines (especially high-revving and turbo gasoline engines). There are far better options on the market.
 
35.gif
 
Originally Posted by Dylan1303

This discrepancy can also result in reduced performance in gasoline engines as the detergent tries to clean the cylinder walls, which compromises the seal between rings and cylinder walls and reduces compression and efficiency.

What are you smoking? So a Cummins ISB with a 19:1, and a turbo blowing 35 psi, think about what you said. And #2. is not a fact. At over 15,000 RPM with a gearbox involved, I can say there is 0 foaming.

Not arguing, but where is this misinformation coming from?
 
Originally Posted by Dyusik
Originally Posted by Dylan1303

This discrepancy can also result in reduced performance in gasoline engines as the detergent tries to clean the cylinder walls, which compromises the seal between rings and cylinder walls and reduces compression and efficiency.

What are you smoking? So a Cummins ISB with a 19:1, and a turbo blowing 35 psi, think about what you said. And #2. is not a fact. At over 15,000 RPM with a gearbox involved, I can say there is 0 foaming.

Not arguing, but where is this misinformation coming from?


Resources:
https://link.springer.com/article/10.1007/s11249-016-0706-7
https://link.springer.com/article/10.1023/B:TRIL.0000044495.26882.b5
https://www.stle.org/images/pdf/STL...unction%20of%20Lubricant%20Additives.pdf
https://www.machinerylubrication.com/Read/31107/oil-lubricant-additives
https://www.machinerylubrication.com/Read/28576/comparing-gasoline-diesel-engine-oils-
https://www.stle.org/images/pdf/STLE_ORG/Newsletter/2019/TL/FilmThicknessAndFrictionOfZDDP.pdf
 
Originally Posted by paoester
Dylan1303, take a look at a fleet average (many) sample iron Fe wear & other study done by Blackstone, and notice Rotella T6 did very well, at or near the top of each item.
https://jalopnik.com/why-expensive-oil-is-a-waste-of-money-1797241527


You didnt get viscosity tested? I bet the t6 sheared out of grade. Only going 3-4k on oil is wasting it. Especially amsoil ss. Also just because your uoa came back good, doesn't mean the oil is protecting like it should.
 
Originally Posted by Dylan1303
Originally Posted by paoester
Dylan1303, take a look at a fleet average (many) sample iron Fe wear & other study done by Blackstone, and notice Rotella T6 did very well, at or near the top of each item.
https://jalopnik.com/why-expensive-oil-is-a-waste-of-money-1797241527
You didnt get viscosity tested? I bet the t6 sheared out of grade. Only going 3-4k on oil is wasting it. Especially amsoil ss. Also just because your uoa came back good, doesn't mean the oil is protecting like it should.
Not my UOAs. You are looking at dozens of runs from each oil pictured. That is a Blackstone Labs published data set. Wear items are there.
 
Originally Posted by Dylan1303
A word to those running Rotella T6 and other HDEOs in gasoline engines because some loudmouth on BITOG or some forum told you to. Don't. I used to tell this to people all the time; that HDEOs don't belong in gasoline engines, but I've learned a lot more lately as to specifically why that is the case.

Reason 1: Primary ZDDP. What most people just call Zinc, ZDDP is an additive package in oil that is known for anti-wear properties. I'll spare you the science behind ZDDP decomposition tiers and the nature of boundary lubrication, but what you have to realize is that there are 200+ formulations of ZDDP and they are not all equal. They come in two main categories: primary and secondary. Primary ZDDP is used mostly as an antioxidant to fight oxidative thickening in engine oils in high-heat applications, of which there are plenty in diesel engines, and is also geared more for lower friction coefficient. By contrast, gasoline engines either use mostly secondary ZDDP with some primary, or exclusively secondary (which is the case of higher quality oils), and is geared more for tribofilm formulation. Basically, your 1200ppm of Zinc in Rotella T6 is not actually protecting better than 800ppm of Zinc API SN spec synthetic oil and certainly not better than a high secondary ZDDP formulated gasoline engine oil.

Reason 2: Anti-foaming. Also referred to as air release, the oil has to release air pockets generated during friction and movement. Rotella is not very good at this, and that's OK when you are running a Detroit Diesel with a 2100RPM redline or even a 6.7 Powestroke with a 3400RPM redline (where the anti-foaming starts to become a bigger issue), not so much when you're running a Subaru FA20 with a 7400RPM redline. Under extended use, this can eventually aerate the fluid enough to cause catastrophic failure, or at minimum power loss.

Reason 3: Detergents/Dispersants. Diesel engines typically deal more with soot handling and dispersion, so the additive package is designed accordingly. On the other hand, gasoline engine detergent packs are designed more to handle acidity. This discrepancy can also result in reduced performance in gasoline engines as the detergent tries to clean the cylinder walls, which compromises the seal between rings and cylinder walls and reduces compression and efficiency.


Now I'm sure I'll get the classic "I've been using this oil and nothing has blown up yet" rhetoric by people who are too cheap to consider better options like AMSOIL, Driven Racing, Motul, and Schaeffer, but that doesn't mean that the product doesn't have its deficiencies simply because you want it to work. I realize people have a higher tendency to believe information that they agree with regarding a cheaper product than a more expensive one, but unless you already knew everything I presented in this post, you ought to reconsider your lubricant choice in gasoline engines (especially high-revving and turbo gasoline engines). There are far better options on the market.


Are you this guy, or are you just copying his post?

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5246334/1
 
Last edited:
Originally Posted by D1dad
What if the hdeo is SN rated?


^ This - plenty of diesel oils are SN rated.....LeoStrop is misinformed.
 
Originally Posted by tundraotto
Originally Posted by D1dad
What if the hdeo is SN rated?


^ This - plenty of diesel oils are SN rated.....LeoStrop is misinformed.


I think you are confusing me with another user. I even use a dual rated HDEO on my ethanol car
lol.gif
 
Originally Posted by D1dad
What if the hdeo is SN rated?

If I had M54 engine, IMO does not matter. That engine is specified for LL01 or at least similarly stringent specification like MB229.5. API SN is a joke compared to those.
 
Originally Posted by cos
35.gif


But the "seeing is believing" demonstrator (where you turn the little crank and the oil sticks to the gears) seems to prove this theory is true!
 
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