Mix Oil Brands for Oil Change?

[Oil Changer]

And there is no harm in the residual left from an oil change. That is what is meant in the standard. That doesn't mean a CATERHAM blend is. Will anything bad happen especially when using the same brand? Most likely not but you're rolling the dice.

Originally Posted By: Shannow
Top up or using up leftovers...versus intentionally setting out to be an oil formulator (what I used to do) are different things.

 

[Shannow]

In order for two oils mixed to be as good as either on their own requires a combination of things to be just perfect, which in practice are highly unlikely to occur.

Firstly, in both original oils, the additives must behave both linearly and synergistically...and they usually don't do either.

e.g.
take the VI and PPD additives of company A and Company B, in a 50:50 brew.

First requirement is that these additives do half the work at half the concentration, and that their contribution in the end result add cumulatively together to achieve the same result, on the new base-stock viscosity.

Given that these additives display highly non-linear behaviour, you can't make the statement that the end result will be the "same"...

The Zinc, moly and Boron type adds are pretty typical...and their ranges in formulated oils are quite wide...

However, if you consider an ILSAC (sub 30 grade) oil, with limits on zinc and phosporous, and other novel FMs to get the job done, versus an HDMO with 30% more zinc/phospohoruos, and a bucket more Calcium, (which is known to be antagonistic towards zinc anti-wear additives).

When mixed, you get a nice "bump" in the additive levels (when comparing the lighter)...but also a depletion when compared to the latter...which one wins, and does the FM still function at 50% concentration, or is the thicker base oil viscosity sufficient to not need the FM ?

In order for a blend to be "as good" as either of it's components, these are the coincidences that have to occur, and clearly that's not likely.

Again, is it going to cause failed engines ?

Almost certainly not.

 

[dkryan]

Originally Posted By: fdcg27
I guess it just bothers me a bit that the OP asked a serious question and got many answers................................................
The standard applied by many seems to be that if the engine hasn't blown up, then whatever they've been doing must be fine.


Lots of people ask a serious question in threads and get many answers. That's because opinions vary depending upon one's experience or perceived knowledge. That doesn't mean those who reply are not taking the OP seriously.

But most of us seem to have kept the OP's question in perspective. He asked about a one-time mix involving a total of five quarts, four of which were the same brand and viscosity and the "add on" quart would also be the same viscosity but a different brand.

His oil sump equals 80% one brand and 20% another brand and all the same viscosity. One time. You shouldn't be bothered a bit nor should the OP.

Now, if he had said his future oil changes would consist of four or five different brands with four or five different viscosities, then the replies would unlikely infer "no worries."

And my engine hasn't imploded or exploded with my oil mix so, yes, it MUST be fine. Even if it is a Nissan.

 

[Shannow]

Originally Posted By: Oil Changer
And there is no harm in the residual left from an oil change. That is what is meant in the standard.


Even then there are still remote risks

http://papers.sae.org/932831/

Quote:
An investigation of an engine field-failure found low-temperature incompatibility to be the root-cause of an engine pumping failure. This was established from an examination of the rheology of the new and used oils. It was later discovered that some SAE multigrade oils that contain higher-cloud-point basestocks are incompatible with other same-W-grade oils that contain VI improvers that have a propensity to interact with wax precursors. The latter oils, which failed the Scanning Brookfield test, but not the TP1 mini-rotary viscometer test, were found to be incompatible with a number of commercial multigrade oils at low-temperature.


Was the residual left after an oil change interacting with a new oil, causing pumpability failure and engine failure.

 

[BHopkins]

Originally Posted By: Shannow
In order for two oils mixed to be as good as either on their own requires a combination of things to be just perfect, which in practice are highly unlikely to occur.

Firstly, in both original oils, the additives must behave both linearly and synergistically...and they usually don't do either.

e.g.
take the VI and PPD additives of company A and Company B, in a 50:50 brew.

First requirement is that these additives do half the work at half the concentration, and that their contribution in the end result add cumulatively together to achieve the same result, on the new base-stock viscosity.

Given that these additives display highly non-linear behaviour, you can't make the statement that the end result will be the "same"...

The Zinc, moly and Boron type adds are pretty typical...and their ranges in formulated oils are quite wide...

However, if you consider an ILSAC (sub 30 grade) oil, with limits on zinc and phosporous, and other novel FMs to get the job done, versus an HDMO with 30% more zinc/phospohoruos, and a bucket more Calcium, (which is known to be antagonistic towards zinc anti-wear additives).

When mixed, you get a nice "bump" in the additive levels (when comparing the lighter)...but also a depletion when compared to the latter...which one wins, and does the FM still function at 50% concentration, or is the thicker base oil viscosity sufficient to not need the FM ?

In order for a blend to be "as good" as either of it's components, these are the coincidences that have to occur, and clearly that's not likely.

Again, is it going to cause failed engines ?

Almost certainly not.


So, would it be best to follow the advice of sicko, and select a top off oil from the PQIA chart, that has a very similar add pack to that of the RP?

 

[wemay]

Originally Posted By: Shannow
BHopkins,
I've been called a hypocrite on these forums for suggesting that blending is not "best practice", while having a blend in the vehicles in my sig...your post is much more conciliatory,

This has always troubled me since the advent of 'gotcha' momments in social media. Since when are we not allowed to change our minds about something. If someone has evidence that is enough to sway your point of view, there is nothing wrong with changing your mind.

 

[Urshurak776]

Hmmm. I picked up 9 quarts of Quaker State Ultimate Durability at the AutoZone end of year clearance. My Kia uses 3.5 quarts per oil change. I figured I would need an oil change top off at some point. Normally I buy Napa full synthetic on sale. Until now I would not have thought twice about dropping in 3 quarts of QS and half a quart of Napa. One uses Moly the other users Sodium. Would you guys hesitate?

 

[demarpaint]

Originally Posted By: Urshurak776
Hmmm. I picked up 9 quarts of Quaker State Ultimate Durability at the AutoZone end of year clearance. My Kia uses 3.5 quarts per oil change. I figured I would need an oil change top off at some point. Normally I buy Napa full synthetic on sale. Until now I would not have thought twice about dropping in 3 quarts of QS and half a quart of Napa. One uses Moly the other users Sodium. Would you guys hesitate?


After Shannow's convincing evidence, and a few other members evidence in more than one of these threads? I wouldn't do it.

 

[Urshurak776]

Originally Posted By: demarpaint
Originally Posted By: Urshurak776
Hmmm. I picked up 9 quarts of Quaker State Ultimate Durability at the AutoZone end of year clearance. My Kia uses 3.5 quarts per oil change. I figured I would need an oil change top off at some point. Normally I buy Napa full synthetic on sale. Until now I would not have thought twice about dropping in 3 quarts of QS and half a quart of Napa. One uses Moly the other users Sodium. Would you guys hesitate?


After Shannow's convincing evidence, and a few other members evidence in more than one of these threads? I wouldn't do it.


Yeah, safer just to grab another quart. Thanks.

 

[Dallas69]

If there was any danger in mixing don't you guys think the oil companies would flat out just say don't mix?

If you think someone on an internet forum knows more than the oil companies then good for you
I have mixed brands,viscosity,you name it over the 50 years that I have been changing oil
I have never had any oil related issues
Am I just lucky?
I don't think so
I can't believe that people can have their minds changed so easy

 

[wemay]

He lives in the Carolina's, no danger.

 

[robo339]

This sure is a long thread should have been titled different "too cheap or lazy to buy one quart" really would have fit it better why does everyone want to mix brand x with brand y when oil is relatively cheap compared to other things in life.... why not just buy the difference to make whatever oil a complete fill and not have to second guess yourself just seems like a no brainer if you are comfortable doing it just do it if you feel you have to ask cuz you are worried about something then dont

 

[fdcg27]

So the Altima is still running fine and hasn't blown up?
I'd be surprised were this not the case, since engines seem pretty tolerant of oil used, as long as they have some and it isn't run too far.
I'd be hesitant to use the mix that you did in a newish car, since it would seem worth it to me to at least use five matching quarts of oil in it, and I practiced this long before I came here and even before the site existed.
Did you run this blend over the winter?
If I mix oils to get rid of the odd quart or two, I'll do so only over the summer, or where I have good reason to believe that there will be no incompatibility between them.
For example, our '99 Legacy got a blend of 3 qts Maxlife SB and 1.5 qts Synpower for its winter change, both in 5W-30. This seemed pretty safe in terms of compatibility and this is a car that's far from new.
To answer the OP's opening post question, if I needed a quart of oil to make up the volume of the RP on hand for an OCI, I'd probably use a quart of either Synpower or NAPA syn, since either oil would seem to be the most compatible with the RP.
The NAPA syn can also be picked up on sale pretty cheaply.
If it becomes expediant to use a blend of oils, as in this case, I'd at least try to blend oils that appear to have similar formulations.
OTOH, the OP or his wife might just run across yet another quart of RP 0W-20 for three bucks, in which case the need to blend anything would be eliminated.

 

[BHopkins]

Originally Posted By: robo339
This sure is a long thread should have been titled different "too cheap or lazy to buy one quart" really would have fit it better why does everyone want to mix brand x with brand y when oil is relatively cheap compared to other things in life.... why not just buy the difference to make whatever oil a complete fill and not have to second guess yourself just seems like a no brainer if you are comfortable doing it just do it if you feel you have to ask cuz you are worried about something then dont


Cheap. Definitely cheap. And I'm confident that I'm in good company. Presumably you included. I see you are so cheap you bought a keyboard which doesn't have a properly functioning period key or caps key. But that's just my

. Because I'm too cheap to spend a nickel on your opinion.

Oh, by the way. I suspect some of these blenders may be very interested to learn that they are "cheap or lazy". Yup, from what I read here, I suspect a good deal of these blenders are anything but.

 

[doublebase]

Originally Posted By: Clevy
Originally Posted By: doublebase
I once mixed a couple of quarts of diesel oil, some generic 5w20 and 2 quarts of Super Tech 5w30 in my Accord. Now the diesel oil wasn't the norm, but almost every oil change I did this "blend", pretty much because of cost and availability. The thing now has 282k miles on it. This last summer I ran almost an exclusive light weight synthetic oil in it...it did burn some, but then again the car was not designed to tolerate a 0 weight oil.



Nonsense. Total,complete and utter nonsense. What's a 0 weight oil anyways. A 0w-20 is a 20 hot. So if there isn't any consumption with a 5w-20 there won't be with a 0w-20.
The 0 means the oil is thinner than a 5 or a 10 at start up. So to believe this in itself causes consumption,or the engine wasn't "designed" for it is nonsense


Nonsense? How's your reading comprehension level "anyways"?

The car - the 1999 Honda Accord - was designed for 5w30. Now fast forward 15 years and 282,251 thousand miles..how's those rings doing at almost 300k miles? Think it's "nonsense" that the car wouldn't be able to handle a 0 weight synthetic in the middle of the summer? Because it didn't, and that's not "nonsense". It drank it like it was water.

 

[Shannow]

Originally Posted By: Dallas69
If there was any danger in mixing don't you guys think the oil companies would flat out just say don't mix?

If you think someone on an internet forum knows more than the oil companies then good for you


Calm down, all I'm saying is that a blend is most likely to be inferior to either of it's components...pretty much what the oil companies say.

My reading indicates that the area of most likely concern is in the area of cold temperature pumping performance...that's statement of fact.

The people who feel that they know more than the oil company chemists are the ones attributing mystical properties to a mixture of two or more different brands, when even the oil companies would suggest sticking to one or the other.

Great, you've mixed forever and nothing's failed...that's not proof that it was advantageous.

 

[OVERKILL]

Originally Posted By: doublebase
Originally Posted By: Clevy
Originally Posted By: doublebase
I once mixed a couple of quarts of diesel oil, some generic 5w20 and 2 quarts of Super Tech 5w30 in my Accord. Now the diesel oil wasn't the norm, but almost every oil change I did this "blend", pretty much because of cost and availability. The thing now has 282k miles on it. This last summer I ran almost an exclusive light weight synthetic oil in it...it did burn some, but then again the car was not designed to tolerate a 0 weight oil.



Nonsense. Total,complete and utter nonsense. What's a 0 weight oil anyways. A 0w-20 is a 20 hot. So if there isn't any consumption with a 5w-20 there won't be with a 0w-20.
The 0 means the oil is thinner than a 5 or a 10 at start up. So to believe this in itself causes consumption,or the engine wasn't "designed" for it is nonsense


Nonsense? How's your reading comprehension level "anyways"?

The car - the 1999 Honda Accord - was designed for 5w30. Now fast forward 15 years and 282,251 thousand miles..how's those rings doing at almost 300k miles? Think it's "nonsense" that the car wouldn't be able to handle a 0 weight synthetic in the middle of the summer? Because it didn't, and that's not "nonsense". It drank it like it was water.




I think you missed his point. The 0w-xx designation is not a weight, it is a classification of the oil's ability to resist thickening; its ability to be pumped and pass the Cold Cranking (CCS) and Pumping (MRV) tests. A 0w-20 passed the cold cranking and pumping tests at -35C and -40C respectively. A 5w-20 passed the cold cranking and pumping tests at -30C and -35C respectively. If it could pass the more difficult 0w-xx tests, it would be a 0w-20. Both oils are still within the range for a xW-20 grade at operating temperature.

Both products are still heavier cold than they are hot. And depending on the viscosity index of the two products, the 0w-20 may actually be HEAVIER than the 5w-20 at your start-up temperature.

 

[robo339]

Originally Posted By: BHopkins
Originally Posted By: robo339
This sure is a long thread should have been titled different "too cheap or lazy to buy one quart" really would have fit it better why does everyone want to mix brand x with brand y when oil is relatively cheap compared to other things in life.... why not just buy the difference to make whatever oil a complete fill and not have to second guess yourself just seems like a no brainer if you are comfortable doing it just do it if you feel you have to ask cuz you are worried about something then dont


Cheap. Definitely cheap. And I'm confident that I'm in good company. Presumably you included. I see you are so cheap you bought a keyboard which doesn't have a properly functioning period key or caps key. But that's just my

. Because I'm too cheap to spend a nickel on your opinion.

Oh, by the way. I suspect some of these blenders may be very interested to learn that they are "cheap or lazy". Yup, from what I read here, I suspect a good deal of these blenders are anything but.


Obviously hit a nerve with this one lol it is cheap and or lazy if you are trying so hard to mix one quart you're over thinking such a simple process mix away I don't care it's been proven by tons of these blenders that it works I'm not debating that I personally think it's lazy to not buy one quart an it's a public forum so if you don't like my reply then dont ask

 

[Dallas69]

I like many others here buy oil when I come across sales so I end up with odd numbers of qts so when I need oil I grab what I have-if I am out of the brand currently in the vehicle I use another
I certainly dont know more than the oil companies but when they say it's ok to mix,I agree

 

[Oil Changer]

You're still missing the point. Shannow explained this quite succinctly.

Originally Posted By: Dallas69
I certainly dont know more than the oil companies but when they say it's ok to mix,I agree