Does it make any sense to mix oils?
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Im running 5qts of Pennzoil Ultra 5W20 (SM) and 1 quart Rotella T6 5W40. Should bring it up just under 5W30 spec, maybe just over if they were both on the high side of their viscosity tolerances.
Hasnt been tested yet.
Also running the nearly identical 5qts Pennzoil Plat. 5W20 and 1 quart Rotella T6 5W40 in the Fusion.
It is untested as well.
Hasnt been tested yet.
Also running the nearly identical 5qts Pennzoil Plat. 5W20 and 1 quart Rotella T6 5W40 in the Fusion.
It is untested as well.
There is enough variety out there no need to mix oils. A mishmash of additives could work against you.
You don't have to be an oil engineer to mix 2 API oils together. It's really not that complicated.
I mix VWB and VR1, for 2 reasons:
1) I want more ZDDP than API SN rated oil allows. VR1 is probably overkill, so I moderate it with VWB.
2) VR1 isn't available in very many viscosities, and 10w30, the grade which makes the most sense for me, is the hardest to find. So sometimes I end up with some quarts of 20w50.
3) bonus reason: sometimes things are on sale, so mixing saves money.
The overall mixture in my engine right now is a thin 15w40. That's using the fancy logarithmic formula, but a simple weighted average is close enough.
As it turns out, this has been measured to work well for hot oil pressure, so if I stick with VR1 I'll be deliberately mixing it to a 40 in the future. But since Defy has come out, I may just switch to that. But what if Defy 10w40 isn't on the shelf at WalMart, or isn't on sale? Mixing will be a valid option.
I mix VWB and VR1, for 2 reasons:
1) I want more ZDDP than API SN rated oil allows. VR1 is probably overkill, so I moderate it with VWB.
2) VR1 isn't available in very many viscosities, and 10w30, the grade which makes the most sense for me, is the hardest to find. So sometimes I end up with some quarts of 20w50.
3) bonus reason: sometimes things are on sale, so mixing saves money.
The overall mixture in my engine right now is a thin 15w40. That's using the fancy logarithmic formula, but a simple weighted average is close enough.
As it turns out, this has been measured to work well for hot oil pressure, so if I stick with VR1 I'll be deliberately mixing it to a 40 in the future. But since Defy has come out, I may just switch to that. But what if Defy 10w40 isn't on the shelf at WalMart, or isn't on sale? Mixing will be a valid option.
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Generally, I don't see any reason to mix oils because as others have stated the oil companies and their engineers probably know more than us. I have however mixed oils a couple of times, once to use some extra oil and another time to top off my truck but both times I used the same grade. Normally, I just stick with same brand and type of oil.
I might catch flak for it but I have always heard that you can mix synthetic and conventional, mix brands, but don't ever mix grades. Even one of my college professors in class one day was explaining the benefits of UOA's and synthetic oil and he said the same thing, that your OK to mix synthetic and non-synthetic, mix brands, but not grades. His reason which made sense to me was that different viscosity oils won't mix properly and could seperate therefore not giving optimal protection.
I might catch flak for it but I have always heard that you can mix synthetic and conventional, mix brands, but don't ever mix grades. Even one of my college professors in class one day was explaining the benefits of UOA's and synthetic oil and he said the same thing, that your OK to mix synthetic and non-synthetic, mix brands, but not grades. His reason which made sense to me was that different viscosity oils won't mix properly and could seperate therefore not giving optimal protection.
Originally Posted By: Donald
There is enough variety out there no need to mix oils. A mishmash of additives could work against you.
2 qts of 10-40 and 2 qts of 20-50....both Castrol GTX High-mileage. I'd like to think that they would have the same additives and all I've done is tweak the weight....hopefully.
There is enough variety out there no need to mix oils. A mishmash of additives could work against you.
2 qts of 10-40 and 2 qts of 20-50....both Castrol GTX High-mileage. I'd like to think that they would have the same additives and all I've done is tweak the weight....hopefully.
I doubt there's proof of this causing issues. I don't normally do it but when you use your leftovers, I have done it many times before. Sometimes different weights and brands, and sometimes same weight but different brands. I've seen 0 issues or negative impact. To each their own!
lol, the 2.0T will see nothing but mixing it's whole life: next fill is synpower 5w-30, w/ a dash of redline and M1 racing 0w-30's on top. I'd like to see the links to the mentioned articles that say mixing is bad - all else I see is a bunch of "I heard..." "could be..." "maybe is..." etc.
ALL mainstream oils, Pennz, Mobil, QS, Valvoline, etc., are clearly labled "compatible with other oils". Only way it would be really bad to mix is if you were to use an oil with a PQIA warning on it, such as "City star", "Everclear" etc. but I know most here would not use the junk oils anyway.
Still probably best to fill with one brand at a time, but I do not hesitate to top off with random leftovers when needed.
Still probably best to fill with one brand at a time, but I do not hesitate to top off with random leftovers when needed.
I've been mixing oils for over 40 years without harm to my engines and I have put on many hundreds of thousands of miles on engines. I have had other issues with the vehicle such as fuel system(carburators especially) but, not the engine itself.
I started mixing in my youth out of nessessity and lack of money. So, I'd mix just about any oil and as many as 5 different grades each being a different brand...No Problems!
Today, I mix differently. More along the lines of 2qts syn and 3qts dino, both being a different brands. Again, No Problems!
I don't think that I can do it better than the Oil Engineers nor do I think that mixing is optimal. I do it because I have so many different brands that I purchaced on sale/discount/rebate/closeout etc. All oils are held in high regard here at BITOG.
I may only have for example, 2 or 3 qts of a particular brand/wgt. But, multipals of brands. I sometimes do but, I often don't have 5, 10 or 12 qts of one brand/wgt.
Recently though, I do have 20 of one brand and 20 of another(dino), 5 of this and 5 of that(syn's) so, I can stay with one single brand/wgt for my OCI's. I will probably still mix 2 syn & 3 dinos
I started mixing in my youth out of nessessity and lack of money. So, I'd mix just about any oil and as many as 5 different grades each being a different brand...No Problems!
Today, I mix differently. More along the lines of 2qts syn and 3qts dino, both being a different brands. Again, No Problems!
I don't think that I can do it better than the Oil Engineers nor do I think that mixing is optimal. I do it because I have so many different brands that I purchaced on sale/discount/rebate/closeout etc. All oils are held in high regard here at BITOG.
I may only have for example, 2 or 3 qts of a particular brand/wgt. But, multipals of brands. I sometimes do but, I often don't have 5, 10 or 12 qts of one brand/wgt.
Recently though, I do have 20 of one brand and 20 of another(dino), 5 of this and 5 of that(syn's) so, I can stay with one single brand/wgt for my OCI's. I will probably still mix 2 syn & 3 dinos
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I've mixed different grade oils of different brands and everything in between. Usually it's to get rid of partial jugs or quarts sitting around. Perfect example, I was running 2.5 qts of Mobil Super HM 5w30 mixed with 2 qts of Rotella 5w40 in my Subaru for the last 5000 miles. Just changed it the other day to M1 0w30. Anyhow, with the mix, it ran smooth as butter and actually seemed to idle quieter.
If the BITOGer will not mix
his brain cannot be fixed!
his brain cannot be fixed!
Originally Posted By: Gabe
Originally Posted By: CATERHAM
A example of a good blend is as follows:
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2559273&page=1
Exactly! That is a perfect example of how a 'good blend' can produce bad UOAs: https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2767720&page=1
I can't believe this guy has his "own blend", and even toots his horn by posting it.
Originally Posted By: CATERHAM
A example of a good blend is as follows:
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2559273&page=1
Exactly! That is a perfect example of how a 'good blend' can produce bad UOAs: https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2767720&page=1
I can't believe this guy has his "own blend", and even toots his horn by posting it.
Who really knows?
WRT the metallic adds one sees in VOAs/UOAs most oils are more alike than different.
They use different proportions of each additive, but even some oils using sodium also use moly, so I don't think you'll see real metalic additive clash.
There are a number of organic additives that might or might not be present in any given oil that we can't see, though.
Vavoline oils typically seem light on metallic adds, but produce very pretty UOAs.
Either Vavoline is using an industry leading basestock, which I doubt, or Valvoline is using organic adds to bolster its oils, which seems likely.
I would avoid mixing across brands or published formulations.
So, I'd mix Pennz with Pennz, QS with QS (both are SOPUS, but different add pack suppliers), Valvoline with Valvoline and so on.
I'd avoid mixing the Mobil Super oils with M1, since they clearly have different add pack designs.
M1 oil do not contain sodium, while MS oils do.
Still, if I had five quarts of different brands and grades to get rid of, I could see putting this mix in a beater for a run.
Might not be optimal, but wouldn't cause any measurable harm either.
Sorry I was unable to provide any real answer to your question.
I don't think there is any clear answer.
I'm not a fan of blending.
Some here are, and I'm pretty sure that their engines will run until the car they're in is junked, just like mine.
WRT the metallic adds one sees in VOAs/UOAs most oils are more alike than different.
They use different proportions of each additive, but even some oils using sodium also use moly, so I don't think you'll see real metalic additive clash.
There are a number of organic additives that might or might not be present in any given oil that we can't see, though.
Vavoline oils typically seem light on metallic adds, but produce very pretty UOAs.
Either Vavoline is using an industry leading basestock, which I doubt, or Valvoline is using organic adds to bolster its oils, which seems likely.
I would avoid mixing across brands or published formulations.
So, I'd mix Pennz with Pennz, QS with QS (both are SOPUS, but different add pack suppliers), Valvoline with Valvoline and so on.
I'd avoid mixing the Mobil Super oils with M1, since they clearly have different add pack designs.
M1 oil do not contain sodium, while MS oils do.
Still, if I had five quarts of different brands and grades to get rid of, I could see putting this mix in a beater for a run.
Might not be optimal, but wouldn't cause any measurable harm either.
Sorry I was unable to provide any real answer to your question.
I don't think there is any clear answer.
I'm not a fan of blending.
Some here are, and I'm pretty sure that their engines will run until the car they're in is junked, just like mine.
I have some very pure oils of different melting points from Roper Thermals. If you mix two oils the combined mix will have a wider melting point temperature. And if you take a mix like that at a temperature that it wants to stay a liquid, but that temperature is below the melting point temperature of one of the oils, that oil will drop out of the combined liquid and condense on the walls of what ever it is in.
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
Originally Posted By: JimPghPA
I have some very pure oils of different melting points from Roper Thermals. If you mix two oils the combined mix will have a wider melting point temperature. And if you take a mix like that at a temperature that it wants to stay a liquid, but that temperature is below the melting point temperature of one of the oils, that oil will drop out of the combined liquid and condense on the walls of what ever it is in.
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
pour points are important property in this consideration;
in general the liquid oils 0W-20 and 15W-50 will not separate so easily given the real life temperatures.
it also depends on the quality of the base oils being mixed and the additives in the final mixture.
I have some very pure oils of different melting points from Roper Thermals. If you mix two oils the combined mix will have a wider melting point temperature. And if you take a mix like that at a temperature that it wants to stay a liquid, but that temperature is below the melting point temperature of one of the oils, that oil will drop out of the combined liquid and condense on the walls of what ever it is in.
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
pour points are important property in this consideration;
in general the liquid oils 0W-20 and 15W-50 will not separate so easily given the real life temperatures.
it also depends on the quality of the base oils being mixed and the additives in the final mixture.
Originally Posted By: mongo161
........Even Mobil 1 states, in it's frequently asked questions section....that all Mobil 1 oils are compatible with one another and can be blended or mixed with each other.
In fact I'm now running 2 different grades of Mobil 1 oils that I picked up at various Kmart store closings in Orlando, Fl. IMO...very good oil at a very good price. ......................
When I look at the M1 FAQ on mixing M1 oils with each other, I don't see any enthusiastic endorsement of the practice, just that "there is no issue with mixing different viscosities of M1 products"
http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Mixing_Oils_Collection.aspx
........Even Mobil 1 states, in it's frequently asked questions section....that all Mobil 1 oils are compatible with one another and can be blended or mixed with each other.
In fact I'm now running 2 different grades of Mobil 1 oils that I picked up at various Kmart store closings in Orlando, Fl. IMO...very good oil at a very good price. ......................
When I look at the M1 FAQ on mixing M1 oils with each other, I don't see any enthusiastic endorsement of the practice, just that "there is no issue with mixing different viscosities of M1 products"
http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Mixing_Oils_Collection.aspx
Originally Posted By: JimPghPA
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
There is of course no such annimal as a 7.5W-35 oil grade and it is a newbie mistake to even suggest such an outcome.
In any blend you need to know the underlying viscosity spec's from the respective PDS of each oil to successfully predict an outcome.
The above mix will likely result in a heavy 10W-30 or light 10W-40.
But you are right about the variance in the molecule size which is why it's best to blend just 0W oils with other 0W oils and 5W-oils with other 5W oils, etc, since their base oils will be of similar viscosity.
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
There is of course no such annimal as a 7.5W-35 oil grade and it is a newbie mistake to even suggest such an outcome.
In any blend you need to know the underlying viscosity spec's from the respective PDS of each oil to successfully predict an outcome.
The above mix will likely result in a heavy 10W-30 or light 10W-40.
But you are right about the variance in the molecule size which is why it's best to blend just 0W oils with other 0W oils and 5W-oils with other 5W oils, etc, since their base oils will be of similar viscosity.
Interesting comments....on mixing M1 oils.
I have a blend mix of M1 oils that have VI that are very close. I used the wideman calculator for the results. IMO....they are in the ballpark for a 10w-30 M1 oil.
M1 recommends that I use only a 10w-30 for my driving style and environment. I don't have the severe weather like the people in Canada or up-state NY.
For a load of 15w-50 for $3 a quart, along with other clearance M1 oils.....I believe it will serve my purpose and run just fine.
As a matter of fact, I ran a blended mix of a gallon jug of PYB 5w-30 SN, GF-5and PP 5w-30, SM, GF-4 last winter and my vehicle ran just fine. Then at the end of the OCI....I added Kreen for the last 1200 miles before the change out.
I have a blend mix of M1 oils that have VI that are very close. I used the wideman calculator for the results. IMO....they are in the ballpark for a 10w-30 M1 oil.
M1 recommends that I use only a 10w-30 for my driving style and environment. I don't have the severe weather like the people in Canada or up-state NY.
For a load of 15w-50 for $3 a quart, along with other clearance M1 oils.....I believe it will serve my purpose and run just fine.
As a matter of fact, I ran a blended mix of a gallon jug of PYB 5w-30 SN, GF-5and PP 5w-30, SM, GF-4 last winter and my vehicle ran just fine. Then at the end of the OCI....I added Kreen for the last 1200 miles before the change out.
Originally Posted By: CATERHAM
Originally Posted By: JimPghPA
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
There is of course no such annimal as a 7.5W-35 oil grade and it is a newbie mistake to even suggest such an outcome.
In any blend you need to know the underlying viscosity spec's from the respective PDS of each oil to successfully predict an outcome.
The above mix will likely result in a heavy 10W-30 or light 10W-40.
But you are right about the variance in the molecule size which is why it's best to blend just 0W oils with other 0W oils and 5W-oils with other 5W oils, etc, since their base oils will be of similar viscosity.
It will still not lead to an optimum/maximum OCI interval... mixing a fully formulated 0w with 0w or a 5w with 5w is not a precise exercise, unless the original base oils properties are known at first for basic calculations!
Originally Posted By: JimPghPA
So if you were to say for example take a 15W-50 and mix it equal amounts with a 0W-20 and call that a 7.5W-35 you may be in for a disappointment when you go to start that vehicle and it is below 20F, because some of the thicker molecules of the 50 will still be of the same chain length, and will still form a thick wax on some of the surfaces.
There is of course no such annimal as a 7.5W-35 oil grade and it is a newbie mistake to even suggest such an outcome.
In any blend you need to know the underlying viscosity spec's from the respective PDS of each oil to successfully predict an outcome.
The above mix will likely result in a heavy 10W-30 or light 10W-40.
But you are right about the variance in the molecule size which is why it's best to blend just 0W oils with other 0W oils and 5W-oils with other 5W oils, etc, since their base oils will be of similar viscosity.
It will still not lead to an optimum/maximum OCI interval... mixing a fully formulated 0w with 0w or a 5w with 5w is not a precise exercise, unless the original base oils properties are known at first for basic calculations!
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