Mixing Oils

[Mainia]

And we've all seen UOA's that have a hodge podge of good oil in it and the UOA came out with average wear. You can get all anal and verbose about it, when it comes right down to it, unless you are redlining it all the time, you will have ZERO issues. Our oils now a days are just that good. Yea, I know all about different additives fighting for space, but is there a reality in this world that those additives are mostly close,and they clearly don't wipe out the other affect. Unless you are at readline all the time it really is a moot point to worry about it. Now I would do it in a naturally aspirated car with mild beating on it, in my turbo car were I have my foot into the boost all the time, maybe. I did one fill go with 3.5 Qt 5-30 Amsoil SS and 1 Qt Redline 0-40 to get more moly into it during late break-in miles. Now, I keep one brands (0-40 Amsoil SS) oil so I do not have any issue if I blow my motor under warranty when I may need Amsoil to back me up. I have UOA backing be up too.

 

[toneydoc]

Sounds like you need to clean up the garage OilUzer

 

[OilUzer]

Originally Posted By: toneydoc
Sounds like you need to clean up the garage OilUzer

ongoing project for over a year now! At least I know where everything is so I am not buying duplicate stuff. After installing overhead storage, throwing away, donating and selling stuff, I still don't have room to use my practically new Total Gym purchased about 10 years ago!

my wife is happy since she can walk in the center garage without tripping over stuff. We need a move to totally get rid of stuff!

 

[Kira]

I'm with you OilUzer. I have "mixed additives" in my garage too. The result is clogging and impassibility.

Gotta heave some stuff. I'm running Frankenbrew myself. Half Mobil1 0W-40 and half Castrol 5W-40.

"Post Katrina Mobil1". News to me. Were refineries consolidated?

 

[CT8]

Originally Posted By: Chevy17
What’s the worst clash the additives could have?
Define clash. The oils have the same additives made by probably a half dozen companies in the world. Unless the additive blenders come up with a new product and fail at properly testing it there will be no problems. I would use up odds and ends of oil with ut worries and I have done so..

 

[blupupher]

These threads always get camps on both sides.

There has never been any evidence either way of what mixing does.

Additive clash and decreased protection are always brought up. Again, no proof, just conjecture.
People say they have run a frankenbrew with no problems, but also again, not proof, just circumstantial evidence.

The point of those that add top off oil (by the millions) don't top off with the same oil that is in the vehicle, and oil makers know this, makes me think there is no real issue with this.
But again, this is just my mind and my opinion. Only you can decide if you want to try it.


If it were my vehicle, I would make a frankebrew of 2 qts of each and not worry about it. Change it when the OLM comes on.
I actually have done this in the past (mixing not only different brands, but different weights and conventional and syn).
I have a few odd qts right now of 0w-20 (PUP, Auto Zone Syn, Mobil 1 AFE) that will be mixed together, and will not change my interval.

 

[StevieC]

Originally Posted By: CT8
Originally Posted By: Chevy17
What’s the worst clash the additives could have?
Define clash. The oils have the same additives made by probably a half dozen companies in the world. Unless the additive blenders come up with a new product and fail at properly testing it there will be no problems. I would use up odds and ends of oil with ut worries and I have done so..


Not only that but think about people using an oil change place that might use another oil than originally used in the first place. They would think of these things or they would have to issue warnings and do complete engine flushes to ensure 100% removal of previous product.

 

[69GTX]

Originally Posted By: Mainia
And we've all seen UOA's that have a hodge podge of good oil in it and the UOA came out with average wear......... I have UOA backing me up too.


UOA doesn't guarantee anything about normal, reasonable, or average engine wear. Only a tear down and taking precise measurements before and after can do that.

UOA can identify "potential" wear elements floating around in the oil. It cannot say where they came from or even given an accurate concentration across the full micron range. It cannot measure wear particles that stay behind in corners of the engine lubrication system, including oil pain, oil pump screen and oil filter.

A UOA is about as accurate in determining the rate of engine wear as the ASTM miscible standard is in determining the performance of mixed oils.

A UOA certainly can help inform you when your engine is headed for self-destruction due to massive amounts of wear elements showing up. By that time, it's too late anyways.

 

[walterjay]

I would just mix it and not do an extended oil change. Been mixing away for years and never a problem.

 

[UncleDave]

Guys have been adding a quart or more to vehicles traveling the roads on long trips since we've had cars and roads.

I can't remember, nor have I ever heard about even one issue that ever came of mixing oils.

Just run a regular OCI.

UD

 

[two4spooky]

Oil is never fully removed in an oil change. OMs would list: dry fill, oil change w/filter and oil change or some such. So you have something like: 6 qts dry fill(new/rebuilt engine), 5 qts oil and filter change or 4.5 qts oil change only. I have never read a manufacturer state only one brand must be used. Certain brands are recommended as a marketing partnership - yes. Required or you will have engine failure - no.

 

[Shannow]

Originally Posted By: blupupher
These threads always get camps on both sides.

There has never been any evidence either way of what mixing does.


I've brought to the table the ones that were severe enough to make it into SAE research.

One was particularly bad when the residual factory fill on a bunch of Toyotas reacted poorly with the PPDs and VIs in the first service fill, and the oils gelled at what were quite modest temperatures and stayed that way to room temperature leading to failure due to pumping.

But those small major cases get discounted as "rare", then again, people like yourself claim that no evidence has been brought forth.

There IS evidence, albeit rare.

The place that it is most likely to manifest is in the "W" performance area, and if you aren't starting at the temperatures that you test that, you won't likely see an issue.

(There's a couple of cases in the diesel section where the other additives didn't play well)

But if you want to score them as "never", go ahead.

But the people that claim
* mixing 2 0W oils always gives a 0W oil
* mixing two API certificated oils results in an oil that will meet all the same API certificate testing

Are dead wrong.

 

[OVERKILL]

Originally Posted By: Shannow
Originally Posted By: blupupher
These threads always get camps on both sides.

There has never been any evidence either way of what mixing does.


I've brought to the table the ones that were severe enough to make it into SAE research.

One was particularly bad when the residual factory fill on a bunch of Toyotas reacted poorly with the PPDs and VIs in the first service fill, and the oils gelled at what were quite modest temperatures and stayed that way to room temperature leading to failure due to pumping.

But those small major cases get discounted as "rare", then again, people like yourself claim that no evidence has been brought forth.

There IS evidence, albeit rare.

The place that it is most likely to manifest is in the "W" performance area, and if you aren't starting at the temperatures that you test that, you won't likely see an issue.

(There's a couple of cases in the diesel section where the other additives didn't play well)

But if you want to score them as "never", go ahead.

But the people that claim
* mixing 2 0W oils always gives a 0W oil
* mixing two API certificated oils results in an oil that will meet all the same API certificate testing

Are dead wrong.


Well covered

 

[UncleDave]

Interesting info.

I wonder what the odds of having a problem would look like numerically?


UD

 

[Shannow]

Originally Posted By: UncleDave
Interesting info.

I wonder what the odds of having a problem would look like numerically?


UD


You personally in Ca ?
Probably never.

If your location was Sioux Falls, and it was winter starting outside there's a much greater chance.

I mentioned Sioux Falls, as there's a particular pattern of cooling overnight that leads to wax precipitation...a whole heap of oils that were compliant at the time failed due to gelling at well above their "W" rating due to that pattern of cooling.

That cooling regime has been incorporated into the MRV test for the current W rating system...the ASTM test for miscibility incorporates none of that.

 

[Shannow]

Originally Posted By: two4spooky
Oil is never fully removed in an oil change. OMs would list: dry fill, oil change w/filter and oil change or some such. So you have something like: 6 qts dry fill(new/rebuilt engine), 5 qts oil and filter change or 4.5 qts oil change only. I have never read a manufacturer state only one brand must be used. Certain brands are recommended as a marketing partnership - yes. Required or you will have engine failure - no.


https://www.sae.org/publications/technical-papers/content/2000-01-2942/
Quote:
A significant deterioration in low temperature pumpability properties (as measured by the mini-rotary viscometer; MRV) was observed in certain commercial-quality engine oils in a taxi field test program. A detailed investigation demonstrated that contamination by carry-over of the factory fill oil in combination with oil aging was the cause of the marked deterioration in low-temperature pumpability properties; no evidence of new oil incompatibility was observed using industry-standard test procedures. A subsequent investigation identified a number of commercial ILSAC GF-2 quality engine oils which also caused large MRV viscosity increases when added in concentrations as low as 1 wt% to used engine oils. A root-cause evaluation established that low concentrations of certain viscosity index improvers caused large MRV viscosity increases when added to used oils. Results from this investigation suggest that a new industry standard may be required to ensure used oil compatibility over a lubricant's normal drain interval.


https://www.sae.org/publications/technical-papers/content/2004-01-1932/
Quote:
Low temperature pumpability has been an important requirement of engine oils for the past two decades. However, until recently this requirement has applied only to fresh oils. Pumpability can deteriorate significantly during oil's life cycle in the engine. Many factors such as combustion byproducts and oxidation can influence oil pumpability at low temperatures.
This paper examines the effects of in-service aging on low temperature pumpability of oils using a variety of industry and proprietary engine tests. In particular, the paper investigates the role of viscosity modifiers in the retention of satisfactory low temperature performance in service. The data show that oils formulated with certain types of viscosity modifiers tend to maintain robust low temperature pumpability throughout their entire stay in the crankcase. Lubricants formulated with another class of viscosity modifiers tend to lose their low temperature performance quite early in their life cycle in the engine. It may not always be possible or practical to compensate for the poor performance of this latter class of lubricants with pour point depressants.

 

[OilUzer]

Is there a Mic drop emoji?

Manufacturers (auto, airplane, etc.) perform extreme temperature testing to expose weaknesses. It would also make logical sense that in general more oil related issues will surface at extreme temperatures! It may not apply to average drivers but under extreme conditions, you get a better edge the more you know!

Even i may consider 0Wx20 or 0Wx16

plus block heaters for winter if I move to Alaska plus no mixing edge ...

 

[Triple_Se7en]

OilUzer....There are only two months of the year (brightest months), where I would even visit Alaska.

If I had to live in the very cold for even two weeks, I would pick the last two weeks of December, visiting with/ helping Santa in the North Pole

 

[UncleDave]

Ca. Shannow- I moved from the brutal cold of the Midwest in the late 80's

The taxi test is interesting. Thanks for posting those up.

If we could somehow add up all the instances of known issues vs the number of times someone mixes two oil without incident - what are the odds of having a problem?

......Is it more or less likely than something that possible but rare like dying in an airplane crash? which is approx -1 in 11M?


How much "risk" is one taking?

UD