mixing oils can eat your engine?

[Solarent]

Originally Posted By: zanzabar
WOW - you guys are going off the deep end here! Let's be realistic, the reason for mixing oils for the vast majority of people that do it is simply because they get "too heavy oil X" on sale and "too light oil Y" on sale and they just happen to need something in between. Especially when you load up on a sale item and have 10 gallons of oil sitting around in your garage (I'm one of these people), there's no reason to go out and pay for new oil when you can brew up a batch of X+Y and make it close enough to the viscosity recommended for the vehicle/climate.


What I don't understand (and maybe you can explain) is why someone buys oil that they know is too heavy or too light, just because it is on sale. Why would you spend thousands or tens of thousands of dollars on a vehicle and then cheap out on oil and buy stuff that is designed for other engines - just because it's cheap? That mentality just doesn't make sense to me.

Like you said, for a short change, most mixing isn't going to kill the engine - but I choose my oils based on availability and performance, and when I find an oil that works well, then I stick with it.

 

[CATERHAM]

Originally Posted By: zanzabar

please find a UOA of a frankenbrew that didn't turn out well. We can find dozens of ones that were fine, but I' have never seen evidence of this "additive clash" in a UOA.

Exactly there isn't any evidence but that won't stop the naysayers from claiming it will ruin your engine.

Here are the facts:
- All base oils used in API and ACEA oils from GP I to GP V regardless of molecular weight are totally miscible with each other.
- Additives do compete with each other. AW with detergents and AW with AW but never to the point of annihilating each other.

The worst thing that can happen from a less the optimal blend is that you could wind up a slightly negative synergy as opposed to a positive additive synergy of a very well crafted premium synthetic oil.
To put it another way, the byproducts of combustion that get into the oil of an IC engine are many orders of magnitude more deleterious to an engines life than some motor oil of a different brand.

 

[surfstar]

Originally Posted By: CATERHAM

Exactly there isn't any evidence but that won't stop the naysayers from claiming it will ruin your engine.

Here are the facts:
- All base oils used in API and ACEA oils from GP I to GP V regardless of molecular weight are totally miscible with each other.
- Additives do compete with each other. AW with detergents and AW with AW but never to the point of annihilating each other.

The worst thing that can happen from a less the optimal blend is that you could wind up a slightly negative synergy as opposed to a positive additive synergy of a very well crafted premium synthetic oil.
To put it another way, the byproducts of combustion that get into the oil of an IC engine are many orders of magnitude more deleterious to an engines life than some motor oil of a different brand.


Neither buster, nor myself, ever said it would ruin an engine. (like I said, the first half of this thread is dismissible)

I have and routinely mix oils to get rid of partial jugs. From now on, I will try to stay within brands, though.

I just do not see the benefit that people perceive they are obtaining by mixing oils. I only see potential negatives (albeit very minor!). I guess the thought of being a backyard oil chemist excites some.

AGAIN - it will not harm your engine. Just doesn't seem optimal to possibly lessen the effectiveness of a well-thought out add pack.

 

[buster]

^1 Well said.

That's what I was trying to say, and I believe I did say that before.

 

[surfstar]

Originally Posted By: buster
^1 Well said.

That's what I was trying to say, and I believe I did say that before.

Now, fuel additives... I'm all about mixing some PEA and TCW3/UCL for a combo maintenance does...

 

[CATERHAM]

Originally Posted By: surfstar

I just do not see the benefit that people perceive they are obtaining by mixing oils. I only see potential negatives (albeit very minor!). I guess the thought of being a backyard oil chemist excites some.

AGAIN - it will not harm your engine. Just doesn't seem optimal to possibly lessen the effectiveness of a well-thought out add pack.

That's the point you don't see the benefit, you also probably like Buster don't have oil gauges in your car so you have never optimized an oil's viscosity to your own particular application.

 

[S65AMG]

If there's no harm in mixing oils, which must be particularly true when the oil is essentially identical except for the amount of VIIs, and if there is a benefit in getting improved viscosity performance, then wouldn't the benefit of mixing outweigh the perceived risks?

 

[BlueOvalFitter]

Originally Posted By: surfstar
Originally Posted By: buster
^1 Well said.

That's what I was trying to say, and I believe I did say that before.

Now, fuel additives... I'm all about mixing some PEA and TCW3/UCL for a combo maintenance does...

Interesting.......mixing fuel additives with mixed oil.....

 

[surfstar]

Originally Posted By: S65AMG
If there's no harm in mixing oils, which must be particularly true when the oil is essentially identical except for the amount of VIIs, and if there is a benefit in getting improved viscosity performance, then wouldn't the benefit of mixing outweigh the perceived risks?


If your engine needs a specific viscosity, you can probably find the exact one you want in a particular oil, as blended off-the-shelf.

Someone who adds a quart of Redline to a 80% Grp II dino sump, is not likely to achieve the performance benefits of either. This "synthetic blend" would likely be better achieved by running one that was formulated as a blend from the beginning.


No harm - but what benefit?

VIIs are not the holy grail of performance specs either. I prefer a shear-resistant 10w30 (preferential to my climate).

This, as many posting on BITOG, is my opinion. I do not have data to backup the claim for or against backyard blending. I just believe that triboligists, that do this for a living, are better at it than I.

 

[surfstar]

Originally Posted By: BlueOvalFitter
Originally Posted By: surfstar


Now, fuel additives... I'm all about mixing some PEA and TCW3/UCL for a combo maintenance dose...

Interesting.......mixing fuel additives with mixed oil.....


Blue - the fuel adds go in the tank, not the sump.

 

[buster]

Originally Posted By: surfstar
Originally Posted By: S65AMG
If there's no harm in mixing oils, which must be particularly true when the oil is essentially identical except for the amount of VIIs, and if there is a benefit in getting improved viscosity performance, then wouldn't the benefit of mixing outweigh the perceived risks?


If your engine needs a specific viscosity, you can probably find the exact one you want in a particular oil, as blended off-the-shelf.

Someone who adds a quart of Redline to a 80% Grp II dino sump, is not likely to achieve the performance benefits of either. This "synthetic blend" would likely be better achieved by running one that was formulated as a blend from the beginning.


No harm - but what benefit?

VIIs are not the holy grail of performance specs either. I prefer a shear-resistant 10w30 (preferential to my climate).

This, as many posting on BITOG, is my opinion. I do not have data to backup the claim for or against backyard blending. I just believe that triboligists, that do this for a living, are better at it than I.



+1

 

[CATERHAM]

Originally Posted By: surfstar

No harm - but what benefit?

VIIs are not the holy grail of performance specs either. I prefer a shear-resistant 10w30 (preferential to my climate).

This, as many posting on BITOG, is my opinion.

I think you mean the VI is not the holy grail of performance spec's, but again you're wrong there as well.
Yes when is comes to many cheap dino 10w30s there can be a shear-resistance benefit but that often doesn't apply to premium synthetics that are formulated with higher VI base oils and higher quality VMs and VIIs. The highest VI oils on the market today use expensive multi-branched shear stable PMA VIIs. Oil shear is not an issue with these oils. Not surprisingly many are OEM oils because a high VI as possible is the holy grail in a motor oil.

 

[OVERKILL]

Originally Posted By: CATERHAM
Originally Posted By: surfstar

No harm - but what benefit?

VIIs are not the holy grail of performance specs either. I prefer a shear-resistant 10w30 (preferential to my climate).

This, as many posting on BITOG, is my opinion.

I think you mean the VI is not the holy grail of performance spec's, but again you're wrong there as well.
Yes when is comes to many cheap dino 10w30s there can be a shear-resistance benefit but that often doesn't apply to premium synthetics that are formulated with higher VI base oils and higher quality VMs and VIIs. The highest VI oils on the market today use expensive multi-branched shear stable PMA VIIs. Oil shear is not an issue with these oils. Not surprisingly many are OEM oils because a high VI as possible is the holy grail in a motor oil.


Pennzoil's new GTL based products don't have exceptionally high VI's. This is likely due to the very minimal use of polymer (and whether they are "awesome" polymers or not is irrelevant to my point) meaning I would expect the oils to be incredibly shear stable. A lubricant is more than just it's VI. It is the sum of all its characteristics including its ability to resist deposit formation under high heat, shear, under high heat shear loads, resist oxidation....etc. To state that one property, its VI, is subsequently some "holy grail" is a bit of a stretch IMHO. Yes, in respect to fuel economy, and subsequently OEM focus, we are seeing a number of high VI lubricants showing up. Usually these are extremely light oils, like the 0w-20's you have lauded on here recently. However, that doesn't mean that this is a characteristic universally accepted as some sort of ultimate metric of lubricant performance. It isn't. It is a characteristic that lends itself to the oil providing the benefit of less resistance on start-up, and ultimately a fuel economy benefit. This is relevant to certain OEM's, particularly in high volume products. However, the quest for this ultra-high VI doesn't seem to apply to the high performance stuff. And if VI were truly what you argue, it would. PU 5w-40 has a pretty mediocre VI, the SN version of M1 0w-40 has a lower VI....etc. Because VI is a compromise too

I was reminded of that with dparm's ENEOS 5w-50 thread where the oil wasn't actually a 5w-50.........

 

[buster]

Quote:
To state that one property, its VI, is subsequently some "holy grail" is a bit of a stretch IMHO.


A huge stretch.

No offense to CATERHAM, but he's waaaaaaaayyy off-base. Focusing on any one characterstic is foolish and thinking VI is the holy grail of specs is just pure nonsense.

 

[CATERHAM]

The single most important aspect of an oil is it's viscosity and you can't talk about viscosity without referencing the viscosity index.

VI is not just important in formulating light oils such as the Japanese OEM 0W-20's. M1 0W-40 is original OEM high VI oil as is the new PU 0W-40.
High VI oils are the trend in racing as well.
Both of Mobil's racing oils are high VI; their 0w50 having a 189 VI.The advantages in racing are clear. An oil that doesn't thin out as much at high temperatures is the holy grail while still being relatively light on start-up.

 

[Cup of Joe]

Quote:
High Viscosity Index
PAOs have inherently high viscosity indexes (VI) while maintaining excellent low-temperature performance. Both properties are critical in protecting engines at temperature extremes. Low temperatures can rob a lubricant of its ability to reach critical parts, while high temperatures can thin and break down an oil, crippling its lubricating ability.

However, two different lubricants with the same viscosity index may perform dramatically differently at low temperatures. Other factors shown on the chart below need to be considered.

Because PAOs are synthesized molecules, they don't contain components that might adversely affect their desired properties. As a result, our PAOs require fewer VI improvers and are less likely to create performance-limiting deposits

From: http://www.cpchem.com/bl/pao/en-us/Pages/HighViscosityIndex.aspx

 

[CATERHAM]

Originally Posted By: buster
Quote:
To state that one property, its VI, is subsequently some "holy grail" is a bit of a stretch IMHO.


A huge stretch.

No offense to CATERHAM, but he's waaaaaaaayyy off-base. Focusing on any one characterstic is foolish and thinking VI is the holy grail of specs is just pure nonsense.

Thank-you very much Buster.
The fact remains that you like many simply don't fully understand the full benefits of high viscosity index oils and the disadvantages of low VI oils.

 

[Cup of Joe]

Here you go then SpectraSyn Ultra™ 1000 from XOM VI 307. Get yourself some and blend away. XOM use it for blending gear and transmission fluids, maybe you can show them the light.

http://www.exxonmobilchemical.com/Chem-E...roductsservices

Why don't we just say there is more to a product then 1 data point on a sheet. What matters is the finished product not the sum of its parts.

 

[OVERKILL]

Originally Posted By: CATERHAM
The single most important aspect of an oil is it's viscosity and you can't talk about viscosity without referencing the viscosity index.

VI is not just important in formulating light oils such as the Japanese OEM 0W-20's. M1 0W-40 is original OEM high VI oil as is the new PU 0W-40.
High VI oils are the trend in racing as well.
Both of Mobil's racing oils are high VI; their 0w50 having a 189 VI.The advantages in racing are clear. An oil that doesn't thin out as much at high temperatures is the holy grail while still being relatively light on start-up.




But I'm not talking about racing oils, I'm talking about high performance oils used for drain intervals in cars like Audi's, BMW's, Mercedes....etc. Oils that have to last longer than a few hours in service.

The VI on M1 0w-40 went DOWN with the SN formulation. PU 0w-40 has no OEM approvals other than Chrysler's, you are better to speak of PU 5w-40, which has almost an identical approval/certification list to M1 0w-40.

And one can certainly speak about viscosity without talking about VI. We talk about HTHS on here all the time without referencing an oil's VI.

M1 0w-40 has a relatively high VI. But isn't lauded for this trait like the 200+ VI OEM 0w-20's that you've spoken about recently, or the ENEOS oils. And when they made the oil more shear stable, the VI went down.

 

[S65AMG]

If a manufacturer recommends a particular brand and type of oil and they also recommend 20 weight below 86f and 30 weight above 86f, there must be a temperature range where a 25 weight in that brand and type would be more optimal than either.

Mixing two recommended oils that are identical apart from weight to produce that 25 weight oil would seem to have no adverse implications and would produce a more optimal viscosity at certain temperature ranges.

The black and white statements that mixing doesn't make sense, even when there is sound thinking and reasoning behind it, do not further the discussion.

I know that CATERHAM has spoken to Mobil about mixing their oils and they have told him it is fine. Several people have talked about mixing oil within the same brand yet what they say gets quoted as if it is an argument for mixing a group I with a group V with fuel additives thrown in.

Please be more nuanced and analytical in your reading and responses. That's what optimizing is about.