Mixing different Weights of oil

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Originally Posted By: Triton_330
Originally Posted By: virginoil
Too many threads now advising against mixing oils even within the same brand.

nO nO AND No.

AT $100 AUD for 5L of Royal Purple in OZ why would one want do that other than play chemist.

Below is an internet net link where mixing of oils was discussed with Royal Purple Tech Teps for street bikes with a view to getting an improvement for the W number. It is not encouraged or recommended.

Evidence no engines have ever blown up is not A scientific reason validating the process It may sound good for the layman.

http://www.superstreetbike.com/how-to/engine-oil-viscosity-mythbusters


I absolutely disagree. While of course I know there is no such thing as "in-between grades" of oils, what I'm disagreeing to is that you shouldn't mix oils.

I say, mix away. Why? All API certified oils must be miscible/mixable in order to obtain, and retain API certification.

Playing chemist? So what. People run Frankenbrews all the time.

Where's CATERHAM when you need him? Of course he has his own special blend named after him, right here on BITOG.

Right now I'm running a mix of two oils in my mother's 96 Explorer. API certified oil is API certified oil. And, we don't run long OCI's anyways. We change around 5k miles or when the OLM pops on. I had some spare bottles of oil left over from previous changes, and her car takes 5 quarts. I mixed 2 quarts of Royal Purple 0w-20 and 3 quarts of Castrol GTX Synblend 5w30. We've had her Explorer for almost 15 years now. For a 1996 Explorer with over 180k miles, she does NOT burn any oil, and has never given us any problems besides it needing a new fuel pump last year, knock on wood.

Mixing brands and grades, so long as all are API certified, is totally fine. It might lower the potential for a longer OCI, but if you don't do long OCI's anyway, it isn't going to matter.

~ Triton

P.S.

Originally Posted By: wemay


Blackstone Labs says it's perfectly fine to mix as does Valvoline and others...
I don't consider Blackstone Labs etc. to be layman nor would I take a manufacturer's word too seriously who obviously wouldn't want you mix their oil brand with another. I have done it once and would do so again if needed but I PREFER to run 5 quarts of the same.


+1



I'm guessing you've missed the numerous posts on this from Shannow as well as this thread:

http://www.bobistheoilguy.com/forums/ubb...922#Post3503439

21.gif
 
Originally Posted By: OVERKILL
Originally Posted By: Triton_330
Originally Posted By: virginoil
Too many threads now advising against mixing oils even within the same brand.

nO nO AND No.

AT $100 AUD for 5L of Royal Purple in OZ why would one want do that other than play chemist.

Below is an internet net link where mixing of oils was discussed with Royal Purple Tech Teps for street bikes with a view to getting an improvement for the W number. It is not encouraged or recommended.

Evidence no engines have ever blown up is not A scientific reason validating the process It may sound good for the layman.

http://www.superstreetbike.com/how-to/engine-oil-viscosity-mythbusters


I absolutely disagree. While of course I know there is no such thing as "in-between grades" of oils, what I'm disagreeing to is that you shouldn't mix oils.

I say, mix away. Why? All API certified oils must be miscible/mixable in order to obtain, and retain API certification.

Playing chemist? So what. People run Frankenbrews all the time.

Where's CATERHAM when you need him? Of course he has his own special blend named after him, right here on BITOG.

Right now I'm running a mix of two oils in my mother's 96 Explorer. API certified oil is API certified oil. And, we don't run long OCI's anyways. We change around 5k miles or when the OLM pops on. I had some spare bottles of oil left over from previous changes, and her car takes 5 quarts. I mixed 2 quarts of Royal Purple 0w-20 and 3 quarts of Castrol GTX Synblend 5w30. We've had her Explorer for almost 15 years now. For a 1996 Explorer with over 180k miles, she does NOT burn any oil, and has never given us any problems besides it needing a new fuel pump last year, knock on wood.

Mixing brands and grades, so long as all are API certified, is totally fine. It might lower the potential for a longer OCI, but if you don't do long OCI's anyway, it isn't going to matter.

~ Triton

P.S.

Originally Posted By: wemay


Blackstone Labs says it's perfectly fine to mix as does Valvoline and others...
I don't consider Blackstone Labs etc. to be layman nor would I take a manufacturer's word too seriously who obviously wouldn't want you mix their oil brand with another. I have done it once and would do so again if needed but I PREFER to run 5 quarts of the same.


+1



I'm guessing you've missed the numerous posts on this from Shannow as well as this thread:

http://www.bobistheoilguy.com/forums/ubb...922#Post3503439

21.gif



So you're just going to say that, "because it doesn't test for additive mixing/clashing, the test does nothing to give the A-okay to mix away"???

*cough*

Tell me, have you not seen the countless UOA's of Frankenbrews that have performed adequately, or more than adequately?

I'll base my opinion on the likes of experience, UOA's, Caterham, and common sense.

Even if the unlikely event occurred where the additives in a mix did clash, it isn't going to blow an engine. More than likely any fallout or crud left from an additive clash would be filtered.

But having said that, I still don't believe it would happen. Too much information has shown us that mixing oils hurts nothing.

I swear, one day I'm going to run 6 different quarts of oil in my truck, all different brands, just to prove my point.

Gosh, if noting else, live and let live.

~ Triton
 
No, what you'd end up with would a product that didn't perform as well as just buying the right product in the first place. That's my point.
 
Mixing doesn't actually give you the exact viscosity you want even if you use the calculator and mixed the right amounts. It'll also harm TBN retention and affect cold cranking performance.

Mixing within the same brand & viscosity is probably totally ok though. For example Pennzoil Platinum with QSUD or Formula shell synthetic since they're all basically the same oil.
 
BTW here is a horrible UOA from a mix of M1 0w30 + M1 racing 0w30:

https://bobistheoilguy.com/forums/ubbthreads.php/topics/2641492/UOA:_M1_0w30_cocktail_-_5k_-_0#Post2641492

After only 5k miles it has sheared out of grade and TBN is only 1.3. Wear numbers are bad as well, this is probably close to a worst case scenario for mixing.
 
Specifications and approvals

Mobil 1 Racing 0w30 is recommended for a wide range of race engine applications. Note: Mobil 1 Racing 0w30 is not recommended for street use.

Mobil 1 Racing 0w30 is recommended for a wide range of race engine applications including highly loaded flat tappet designs such as NASCAR Cup engines.Mobil 1 Racing 0w30 is designed for use by professional, amateur and weekend racers.Mobil 1 Racing oils are not recommended for 2-Cycle or aviation engines, unless specifically approved by the manufacturer.




I'm sure we can find as many extremes in mixed oil uoa as non-mixes (arguable). But I don't think M1 Racing is an API certified oil...
 
I wouldn't mix a 'not for street use, racing oil' with an oil certified or approved for the street. I would mix API with ACEA etc though. Plus, low TBN in a race oil is the nature of the beast. Below is a mix using racing and street oil that had good results...
Again, we can all find almost any result we want on the internet. Tail wagging the dog?
wink.gif


http://www.bobistheoilguy.com/forums/ubb...len#Post3590067
 
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I mixed different weights of oil once and I will NEVER, EVER do that again. It caused an explosion with so much force it blew the hood right off its hinges and 50 ft. up into the air.
 
Originally Posted By: Triton_330
Right now I'm running a mix of two oils in my mother's 96 Explorer. API certified oil is API certified oil.

What happens when I mix my CJ-4/SM; ACEA E7/E9; Caterpillar ECF-3, ECF-2; Cummins CES 20081; Detroit 93K218, 93K214; Deutz DQC III-10 LA; Mack EO-O Premium Plus, EO-N Premium Plus 03; MAN M 3277; MB 228.31, 235.27; MTU Oil Category 2.1; Volvo VDS-4, VDS-3 Delvac 1 with an A5/B5 SN/GF-5 dexos1 5w30? I doubt that in an average application, there would be an issue. However, which builder approvals would still stand? Which ACEA spec would stand? Would it still be dexos1? Which API spec would stand?

I created an intentionally absurd example. However, with few exception, there aren't a lot of reasons I'd choose to mix. There are reasons to mix and reasoned approaches to mixing, but there are plenty of viscosities available on the shelf.

If you want a thin 0w-30, there are things like Petro-Canada Supreme Synthetic 0w30 or M1 AFE. If you want a thick 0w-30, take GC or a 0w30 HDEO.
 
Hi,

Originally Posted By: OVERKILL
No, what you'd end up with would a product that didn't perform as well as just buying the right product in the first place. That's my point.


Correct, why do it when there are many great products available today? - and I may say like never before!!
 
The purpose of this forum is to debate the subtle nuances of oils and the like. If oil is just oil to you, why are you here? In general, there is little we can purposely do to seize an engine and mixing oils sure isn't one of them, but mixing is not optimal; which is why most of us are here, to make things optimal.

And why do you put CATERHAM on a pedestal? What makes his opinion worth more to you than others? He's left a lot of unanswered questions on the table.

Originally Posted By: Triton_330
Gosh, if noting else, live and let live.~ Triton
 
Last edited:
Originally Posted By: Shannow
Garak, according to the touted interchange rules...you couldn't even claim that it met SN.


So I can't mix my old leftovers and create my own 'super oil"?

What a disappointment!
 
Originally Posted By: Oil Changer
but mixing is not optimal; which is why most of us are here, to make things optimal.


That's just an opinion. There are other opinions. I think there are cases when mixing oils can result in an oil that is better for the situation, aside from obvious practical benefits of convenience you often get; e.g. thinning or thickening your car's oil with a topoff admix, as the seasons and climate changes.
 
Of course you can mix!!
I have done changes with what I had on hand many times over the years with no engines destroyed
Any API certified oil can mix with another
Too many here are oil anal
 
Originally Posted By: Shannow
Garak, according to the touted interchange rules...you couldn't even claim that it met SN.

Agreed. Even if I grabbed Delvac 1 LE 5w30 in CJ-4/SN, with similar builder approvals to the 5w-40 I'm running, I'd still be in the same boat with a mix - a bunch of builder approvals, ACEA specs, and so forth that no longer are worth the paper on the label.

Oil Changer: In fairness to CATERHAM and with his blend, at least in his own use, to the best of my knowledge, it's fairly reasoned. He's not one to extend OCIs, so it's not quite like he's expecting the long drain performance of M1 0w-40 along with the thin viscosity of TGMO. And, there are cases where mixing is encouraged or at least condoned by the oil company.

Personally, though, I don't think my knowledge is sufficient to second guess professional blenders. Anything that I think is lacking on store shelves (i.e. if I wanted a really high ZDDP 5w30 with HDEO type HTHS for the F-150 for some odd reason, without paying an enormous price for a boutique) isn't going to be successfully created in my garage, and I suspect I'll be better off with one of the multitude of products on the shelf today.

As Doug points out, when have we seen the choice and quality of products that we do today?
 
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