Mixing viscosities and or brands OK or NO?

[kschachn]

Yesterday‘s thread on the exact same subject:

https://bobistheoilguy.com/forums/threads/mixing-oil-to-top-off.348968/

 

[kschachn]

This is my sense, too.

All API licenses include a requirement to pass ASTM D6922.

https://bobistheoilguy.com/forums/threads/mixing-oil-to-top-off.348968/#post-5962762

 

[SR5]

Definitely don't......but when you do, post your mix here, and join the club.
https://bobistheoilguy.com/forums/threads/post-your-latest-frankenbrew.340199/

 

[SR5]

Also this thread is worth reading
https://bobistheoilguy.com/forums/threads/messing-around-with-mixing-viscosities.272647/

 

[TnT_M]

I personally still struggle with mixing different brands and viscosities even though it will not make any difference or cause any problems. Just old school I guess.

To answer the question mix away with no worries.

Just my $0.02

 

[wpod]

Any issues on mixing Shell Rotella Gas Truck 0w20 with Shell RGT 5w30 in equal amounts? I have a large amount of 0w20, prefer to run 5w30, although Ford recommends 5w20 for my 2002 F350 6.8L V10 with 200k miles. This truck sits a lot, but when it is run it typically has a 10k gooseneck behind it.View attachment 81126View attachment 81127

Why would there be issues? Other than maybe the blend could be too thin. People are so market driven.

 

[wpod]

Isn't part of the API certification that it can be mixed with another oil of the same API class oil without negative affects?

People tend to let their opinions get in the way of facts.

 

[wpod]

I used to think it was ok to mix different brands which have different add packs, base stocks, etc, until I talked to the chemists in HPL's lab. When I asked them this question, they said no, do not mix different formulations together and think everything will be ok in the crankcase. The only way you can possibly know if the oils will work well together is to test the frankenbrew in the lab. The main problem they see if foaming. They have seen a perfectly functioning engine oil that will foam like nobody's business when just a small amount of another additive is added. They have even see oil foam when an anti-foam agent is added! Additive clash is real and I needed no more convincing not to mix oils.

What is the difference in the oil additive packages. No not the snake oil type additive packages. Here is
Amsoil's Signature Series cut and paste from their data sheets . Is Amsoil that special to be able to be compatible and other major producers or bottlers aren't ?



COMPATIBILITY
AMSOIL Signature Series Synthetic Motor Oil is compatible
with other conventional and synthetic motor oils. Mixing other oils
with AMSOIL motor oils, however, will shorten the oil’s life expectancy and reduce its performance benefits. AMSOIL does not support
extended drain intervals where oils have been mixed.
Aftermarket oil additives are not recommended for use with
AMSOIL synthetic motor oils.
TECHNICAL SERVICES

 

[wpod]

COMPATIBILITY AMSOIL Signature Series Synthetic Motor Oil is compatible with other conventional and synthetic motor oils. Mixing other oils with AMSOIL motor oils, however, will shorten the oil’s life expectancy and reduce its performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives are not recommended for use with AMSOIL synthetic motor oils. TECHNICAL SERVICES


Another one of Amsoils ,,,COMPATIBILITY AMSOIL Synthetic Heavy Duty Diesel & Marine Oil is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oil, however, will shorten the oil’s life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives are not recommended for use with AMSOIL motor oils.



These are a cut and paste from the Amsoil's data sheets

 

[wwillson]

What is the difference in the oil additive packages. No not the snake oil type additive packages. Here is
Amsoil's Signature Series cut and paste from their data sheets . Is Amsoil that special to be able to be compatible and other major producers or bottlers aren't ?



COMPATIBILITY
AMSOIL Signature Series Synthetic Motor Oil is compatible
with other conventional and synthetic motor oils. Mixing other oils
with AMSOIL motor oils, however, will shorten the oil’s life expectancy and reduce its performance benefits. AMSOIL does not support
extended drain intervals where oils have been mixed.
Aftermarket oil additives are not recommended for use with
AMSOIL synthetic motor oils.
TECHNICAL SERVICES

How Amsoil can make the claim that "AMSOIL Signature Series Synthetic Motor Oil is compatible with other conventional and synthetic motor oils."

How could they possibly know how the frankenbrew will perform? How could they possibly know if it will foam?

 

[kschachn]

Why would there be issues? Other than maybe the blend could be too thin. People are so market driven.

If a 20-grade is permitted, how could any mixture of a 20 and 30-grade be too thin?

 

[The Critic]

How Amsoil can make the claim that "AMSOIL Signature Series Synthetic Motor Oil is compatible with other conventional and synthetic motor oils."

How could they possibly know how the frankenbrew will perform? How could they possibly know if it will foam?

I think we need to get a better understanding of ASTM D6922 and what that test entails. If what some of the others are staying is correct, then mixing oils should not result in the foaming issues you described/witnessed. If it does, is it possible that this is due to the experiment being conducted with non-API approved oils?

 

[kschachn]

Here is a rogue copy of the test. It is for homogeneity and miscibility in a static test environment. The only time there is agitation is to initially mix the oils and foaming is not a designated result of the test.

http://www.kelid1.ir/FilesUp/ASTM_STANDARS_971222/D6922.PDF

 

[Shel_B]

My curiosity is because I'll end up with a bunch of containers with a quart or so of oil left in them from different brands.

Why keep changing brands? Find an oil you like and stick with it.

 

[The Critic]

Why keep changing brands? Find an oil you like and stick with it.

There is this thing called price - and staying cost-competitive for your audience. If you don't do it, your competitors will.

 

[wwillson]

Passing ASTM D6922 doesn't mean the oil won't foam.

 

[Shel_B]

There is this thing called price - and staying cost-competitive for your audience. If you don't do it, your competitors will.

What!? As an end-user you have competitors? Or are you in a situation where you're supplying oil to customers?

 

[JeffKeryk]

I used to think it was ok to mix different brands which have different add packs, base stocks, etc, until I talked to the chemists in HPL's lab. When I asked them this question, they said no, do not mix different formulations together and think everything will be ok in the crankcase. The only way you can possibly know if the oils will work well together is to test the frankenbrew in the lab. The main problem they see if foaming. They have seen a perfectly functioning engine oil that will foam like nobody's business when just a small amount of another additive is added. They have even see oil foam when an anti-foam agent is added! Additive clash is real and I needed no more convincing not to mix oils.

IMO, this statement is far too vague, rendering it meaningless. You simply cannot test everything, or even a meaningful sample.
The possible Frankenbrews is endless, which means you could never test every combination and permutation. Not even close.
Old parrafin oil with Amsoil perhaps? In whatever quantities?
Is it 5 qt Mobil 1 0w20 plus 1/2 qt Mobil 1 5w20 or Valvoline 2.5 qt 0w20 plus 2.5 qt 30w parrafin based?
Overdue for a service oil plus 1 qt new Kirkland? 10 different oils?

In the real world, for 100 years people have been mixing oils. IMO and experience, an underfilled crankcase is a far bigger problem.
Just my 2 cents.

 

[The Critic]

What!? As an end-user you have competitors? Or are you in a situation where you're supplying oil to customers?

I guess I was speaking from a business position.

But even for an end user, price is always a factor. If you are trying to manage your costs, changing brands is inevitable in order to keep up with sales.

 

[JeffKeryk]

I guess I was speaking from a business position.

But even for an end user, price is always a factor. If you are trying to manage your costs, changing brands is inevitable in order to keep up with sales.

And what if your car is overdue for a service and that particuliar oil is not found at Walmart?