Mixing Oils in a 1997 Landcruiser

[Ducked]

Originally Posted By: rooflessVW
Or you could buy a 5qt jug of GTX and do an OCI with GTX 20W-50.



That seems to make most sense. Maybe do the winter-summer thing.

I mix oils and am not worried by it, BUT

(a) I'm mixing straight weight into a multi-grade, which I'd guess carries less chance of unforseen interactions than two multigrades.
(b) I don't see sub-zero temperatures
(c) My car has zero market value, and, though I don't want to kill it, I'll probably have to scrap it when I leave Taiwan anyway.

A Land Cruiser is a lot less disposable.

 

[Triple_Se7en]

Originally Posted By: Dallas69
I have never seen any damage from mixing oils.
Has anyone here?
No matter what blend you comes up with it is still oil.
Not molasses,goop,cement or anything to have nightmares over.


I mixed synthetics with conventionals for more than a decade. Truck still only used a half-quart between oil changes and didn't smoke at 250K - 17 years after I bought it new.

Mix away and worry-not. I did these synblends for 6K OCIs and the engine purred as I drove it to the junkyark, all rusted away from Michigan's salty winters.

 

[njohnson]

Here is what Mobil is saying about mixing their oils:

https://mobiloil.com/en/faq/product-faqs?View=20&Page=1


"Is it okay to mix conventional motor oil with Mobil 1™ motor oil?



Yes. Mobil 1 is fully compatible with conventional motor oils, semi-synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 will be reduced by diluting it."

"My car doesn’t require synthetic motor oil. Can I switch from conventional motor oil to Mobil 1™ Annual Protection motor oil?



Switching from conventional motor oil to Mobil 1 Annual Protection motor oil is perfectly acceptable. Mobil 1 Annual Protection motor oil is compatible with conventional oils, high mileage oils, synthetic blends and other full synthetic oils. Engine flushing is not required."

" Will I need to add any oil to my vehicle during my one-year Mobil 1™ Annual Protection oil change? Do I have to monitor my oil level or add Mobil 1 Annual Protection motor oil during the extended oil change interval?




Regular maintenance cannot be ignored while using Mobil 1 Annual Protection motor oil, including checking your vehicle’s oil level regularly and adding oil if necessary. While Mobil 1 Annual Protection motor oil provides excellent protection against oil burn-off, your vehicle’s oil consumption is primarily a function of the engine design. Some engines use more oil than other engines. Check your engine oil level regularly to ensure that your engine has the proper amount and add if necessary.

A best practice is to use the same oil (brand/type/viscosity) for top-offs as what is currently in your engine. While Mobil 1 Annual Protection motor oil is compatible with other oils, mixing oils may reduce the effectiveness of Mobil 1 Annual Protection motor oil and is not recommended."

 

[Shannow]

Originally Posted By: Dallas69
Come on now.
You find rare obscure cases where problems may have happened anyway. In sub zero temps a lot of things can go wrong.
And a tractor?
Tractors in most cases are not taken care of very well.
If you don't run the correct wt you can have issues .
Let me rephrase my post to say any approved oils of the same wt can be mixed and be OK in 99% of the time.
There.
It doesn't turn into something other than oil.


speaking of "come on"...You and others keep quoting NEVER.

as to "obscure reference", that's an SAE paper...there are others, including a taxi fleet of Toyotas that failed in above freezing conditions (I've given you that reference before, it's the one that I was referring to as you keeping forgetting...clearly), when the factory fill and the first service fill failed to play nicely, and the oil gelled at quite reasonable temperatures.

It DOES and HAS happened.

and as I keep banging on to you NEVER types, the point at which it usually manifests is in the area of cold temperatures, Pour Point Depresants, and VII interactions.

Precisely where my "obscure" SAE papers find the problems.

You "mix away"..NEVER...types either intentionally ignore , or worse willfully dismiss this clear, and obvious problem.

Clearly, in order for to oils mixed to even break even, every single additive in the oil, and the interaction of the basestocks must ALL work linearly in their effect, and cumulatively in total...look at the effect versus treat rate of any of them, they clearly aren't linear, so ASSumption number one is clearly invalid.

And protection from any potential problem is simply as cheap and easy as buying a couple quarts of oil.

 

[Shannow]

Originally Posted By: njohnson
" Will I need to add any oil to my vehicle during my one-year Mobil 1™ Annual Protection oil change? Do I have to monitor my oil level or add Mobil 1 Annual Protection motor oil during the extended oil change interval?




Regular maintenance cannot be ignored while using Mobil 1 Annual Protection motor oil, including checking your vehicle’s oil level regularly and adding oil if necessary. While Mobil 1 Annual Protection motor oil provides excellent protection against oil burn-off, your vehicle’s oil consumption is primarily a function of the engine design. Some engines use more oil than other engines. Check your engine oil level regularly to ensure that your engine has the proper amount and add if necessary.

A best practice is to use the same oil (brand/type/viscosity) for top-offs as what is currently in your engine. While Mobil 1 Annual Protection motor oil is compatible with other oils, mixing oils may reduce the effectiveness of Mobil 1 Annual Protection motor oil and is not recommended."


Originally Posted By: Pennzoil
The physical results may be very much as you expect i.e. viscosity is likely to be predictable following well known physical laws however the chemical effects are highly unpredictable. Wear performance is not dictated solely by the amount of wear protecting additives in an oil, the efficacy (effectiveness) of the additives must also be considered. Efficacy can be negatively impacted by changing the balance of a formulation package. The approach you suggest could conceivably result in poorer performance, I would recommend choosing a single tier of product, and Pennzoil Platinum has been designed to offer complete protection including unsurpassed wear performance.

 

[Shannow]

Originally Posted By: Shannow
You "mix away"..NEVER...types either intentionally ignore , or worse willfully dismiss this clear, and obvious problem.

Clearly, in order for to oils mixed to even break even, every single additive in the oil, and the interaction of the basestocks must ALL work linearly in their effect, and cumulatively in total...look at the effect versus treat rate of any of them, they clearly aren't linear, so ASSumption number one is clearly invalid.

And protection from any potential problem is simply as cheap and easy as buying a couple quarts of oil.


Here's Evonik's look at PPDs
http://oil-additives.evonik.com/sites/lists/RE/DocumentsOA/ppd-treatise-en.pdf

Read that and tell me how the armchair assumption that random mixing will all be good and always works...

 

[kschachn]

Originally Posted By: Dallas69
Come on now.
You find rare obscure cases where problems may have happened anyway. In sub zero temps a lot of things can go wrong.
And a tractor?
Tractors in most cases are not taken care of very well.
If you don't run the correct wt you can have issues .
Let me rephrase my post to say any approved oils of the same wt can be mixed and be OK in 99% of the time.
There.
It doesn't turn into something other than oil.


Yes, an oil with no certifications nor specifications, and no guarantee that it meets the "W" rating.

 

[Shannow]

Originally Posted By: kschachn
Yes, an oil with no certifications nor specifications, and no guarantee that it meets the "W" rating.


but (probably) nothing will blow up, which is, apparently all that's required of oil these days on BITOG.

 

[Shannow]

Just for giggles...

http://papers.sae.org/961095/

 

[zeng]

Originally Posted By: Shannow
Originally Posted By: kschachn
Yes, an oil with no certifications nor specifications, and no guarantee that it meets the "W" rating.


but (probably) nothing will blow up, which is, apparently all that's required of oil these days on BITOG.

.... in the hands of granny drivers, in particular.

 

[Dallas69]

Somehow I've missed all the broken down cars with gummed up motors on the side of the road and overfilling the garages.
I guess I have to look closer cause with thousands of cars running mixed oils I'm sure they are there.
Somewhere.

 

[RooflessVW]

No one is saying mixing T6 and Castrol GTX is going to make his engine fail. We are simply saying that the results of such a mix are unpredictable and certainly not optimal.

Keep running the T6, since you'll have to buy some anyway for your mix, or buy a $12.97 jug of GTX 20W-50 and run it for an oil change. I don't get the fascination with mixing. It doesn't save money. It isn't ideal for your engine.

All this over $6 in oil. SIX DOLLARS WORTH OF CASTROL GTX.

 

[Shannow]

Originally Posted By: Dallas69
Somehow I've missed all the broken down cars with gummed up motors on the side of the road and overfilling the garages.


Find one single quote where I (or anyone else for that matter) have suggested that pile of failed engines...(note to others that this particular strawman, and my request that the poster validate his statements have always gone unanswered)

 

[Garak]

Originally Posted By: Dallas69
Somehow I've missed all the broken down cars with gummed up motors on the side of the road and overfilling the garages.

That never was the point. There is the issue of doing things in an optimal fashion, though. For one, I wouldn't like playing games like that in a Saskatchewan winter. If something does manifest itself, it will be under poor weather conditions.

Secondly, some people are, better or for worse, married to a certain oil spec, or do extended drains. If one is going on long drains and using half Amsoil SS and half Mobil 1 EP, I doubt that Amsoil and Mobil would both stand behind the blend and split the difference if a warranty claim were ever made.

Basically, if you live in a nice climate and don't push your OCIs, do whatever you want. Heck, even if you do live in a cold place and run extended OCIs, do what you want, too.

 

[Dallas69]

I don't know of anyone who has had any oil related engine problems with mixing brands of oil.
I have been around cars my entire life and have never seen any issues myself.
Having first hand knowledge is validation enough in my book.
Oil companies would flat out say don't do it if it was not OK,not just not optimal or won't stay in spec.
If anyone here has first hand knowledge of engine problems solely caused by mixing please speak up.
I've been here awhile now and in a past life longer and never once saw any posts on problems.

 

[kschachn]

Originally Posted By: Dallas69
I don't know of anyone who has had any oil related engine problems with mixing brands of oil.
I have been around cars my entire life and have never seen any issues myself.
Having first hand knowledge is validation enough in my book.
Oil companies would flat out say don't do it if it was not OK,not just not optimal or won't stay in spec.
If anyone here has first hand knowledge of engine problems solely caused by mixing please speak up.
I've been here awhile now and in a past life longer and never once saw any posts on problems.


Once again you miss the point.

 

[cmhj]

Time for another beer run

 

[zaffo757]

God knows what funky brew you'll have running round your crankcase!

Hopefully it does not give you heartburn.

I'm running 0w5 because it is 1/4th as good as 0w20.

 

[650NutKase]

Couple of issues I see in this thread. This forum is very wishy washy when it comes to mixing. One month everyone will rave about how their "Home brew" preformed in their latest UOA, while the next month, they hate any and all mixing of lubricants. Here is what I don't get, if mixing oils is bad, then optimally, the entire engine should be let to drain bone dry before refilling with another brand of lube. You never get out 100% of the oil inside the engine during a normal change, wouldn't this fall under the "no-no policy"?? Also, the articles listed are over 10 years old. I would think that the oils today are much more robust in handling additive clash. Lastly, we have all been on that 1 road trip where we check the oil and it's a quart low. The local gas station that you're at doesn't carry the PUP 0w40 that you love to have in your engine, so what do you do?? That's right, you opt for a 10w30 or 40 to "get you down the road". See where I'm going with this? I'm not saying it's ideal, but I seriously doubt, with today's oils, that there will be any issues in a reasonable ratio. Ie. no 80% Lucas, 20% 20w50

 

[Shannow]

Originally Posted By: 2012AccentSE
Here is what I don't get, if mixing oils is bad, then optimally, the entire engine should be let to drain bone dry before refilling with another brand of lube. You never get out 100% of the oil inside the engine during a normal change, wouldn't this fall under the "no-no policy"??


Logical fallacy...the fact that you can't 100% drain an engine doesn't make mixing a positive...you just can't cut it that way.

Unavoidable doesn't justify intentional.

The miscibility standard just says that they can be mixed, heated, frozen, heated again, and don't split like salad dressing, nor blow chinks...guarantees absolutely nothing else.


Originally Posted By: 2012AccentSE
Also, the articles listed are over 10 years old. I would think that the oils today are much more robust in handling additive clash.


You would think...do you have a scientific basis for that thinking, or is it just that you would expect, in the absnce of evidence ?

What has changed that would lead you to that position ?

The statements from Pennzoil are in the front page of BITOG and are pretty "fresh" in comparison.

The VOA I linked to is pretty fressh too (weeks) with indeterminate "chunks" suggested by Blackstone as additives in the scheme of things.


Originally Posted By: 2012AccentSE
Lastly, we have all been on that 1 road trip where we check the oil and it's a quart low. The local gas station that you're at doesn't carry the PUP 0w40 that you love to have in your engine, so what do you do?? That's right, you opt for a 10w30 or 40 to "get you down the road". See where I'm going with this?


Same logical fallacy as the first, unable to avoid does not justify the intentional mixing.

Originally Posted By: 2012AccentSE
I'm not saying it's ideal, but I seriously doubt, with today's oils, that there will be any issues in a reasonable ratio. Ie. no 80% Lucas, 20% 20w50

Combined with the above logical fallacies, this is the "nothing will blow up" conclusion...and it's right, nothing blows up...not because of the unavoidable issues that are raised previously making the situation better, just that blow ups are exceedingly rare.

The point is a poster asked for advice...so which advice is more sound ?

* no-one has ever had or posted evidence that there's ever a problem (point there is patently incorect)
* you will never have a problem
* nothing blows up.

or

* there HAVE been problems reported, they are rare, and they typically relate to cold temperature performance (here's a few - which makes point 1 above factually incorrect (I fall short of intentional lie)).
* your mix will lack proof of any of the approvals that are listed on either of the bottles
* When mixing, chemistry interactions can be unpredictable.
* best defence is no be there, and not mix.

If you were an absolute newbie asking advice, on a knowledgeable forum, which advice qould you prefer to recieve ?

advice that lists possible side effects (like one would expect from a medical practitioner for example), or boldaaa statements that aren't based on the truth, and deny the fact that issues have ever occurred ?