Mix Oil Brands for Oil Change?

[Shannow]

Originally Posted By: wemay
The testing of every mixture possible would be impossible. Because those mixtures have not and will not be tested (of coarse), the outcome is uncertain. Therefor, assuring they meet any spec would be disingenuous.


Thus the standard uses 6 reference oils for all tests, it isn't possible to test every combination.

(as an aside, my last blend, that I shortchanged last week appears to have had impact on the cold flow properties...might explain elsewhere)

 

[dlundblad]

My moms Elantra received frankenbrew'd oil changes the last 3 OCI's. I didnt notice any cold start suffering, but I imagine it being a "newer" car had something to do with it. A strong starter and battery make a huge difference.

 

[wemay]

Originally Posted By: Shannow


(as an aside, my last blend, that I shortchanged last week appears to have had impact on the cold flow properties...might explain elsewhere)


Looking forward to it.

 

[Shannow]

wemay,
parts place in town had Penrite 5W30 "racing" oil (PAO/Ester, loads of zinc and boron), on closeout, and I got the last 5L for $25...I snatched it.
Later, I bought their last M1 5W50 for $26, and planned my super brew.
Made a 4L/3L blend, for a "5W40", thinking to get HTHS around 3.6ish...started the OCI nearly a qt short, to fine tune. That was May last year, before we tripped the US for a month.

Meantime, I ran 5W20 synthetic (Nulon, no teflon in their engine oils, but have MoDTC) in my mower over winter - wasn't cold enough to kill the grass, so I tried 5W20 (didn't like the "knock" that the engine made to first couple of power strokes)

Talking to Penrite, they confirmed the HTHS of the Racing 30 was 3.4, so my brew was too thick, I had room in the sump, and a 5W20 that I no longer wanted to play with in my mower.

So filled to the full mark with the 5W20 to get closer to my target.

About that time, I started reading more on what the standard offered.

http://www.bobistheoilguy.com/forums/ubb...922#Post3503439

My Nissan normally drops a litre quite suddenly at 7,500 to 8,000km into an OCI, 10,000km OCIs on the diesel engine...it did it this time at 5,000km.

Only member of the original brew that I had left in the stash was M1 5W50, and I didn't want to add that.

So added some Caltex C3 that I had (had worked out that a parts chain synthetic was Caltex C3 synth, so bought it at the time)...topped up with that.

Then chickened out, concerned that the usual pattern of consumption was changed with that brew before the Caltex was added, and not going to do a winter on a more frankenbrew...so dumped it at 5,000 and a handful of km...Edge 5W30 A3/B4 replaced it, and a new filter.

Have been playing with 0W, 5W, 10W, and 20W of various grades (20, 30, and 40 (and 50 and 60) in my freezer (-20C), just to see what happens, and the aged in an engine synthetic brew is pretty poor compared to a semi 10W30, not as bad as a good SAE 30, and lots worse than M1 5W50 (which was indistinguishable from the 5W20 in the same "test").

Not scientific in any real way except for the fact that the freezer is -19 or -20 C pretty consistently. The cold temperature performance of a finished lube is allowed to drop a grade and still remain in grade, and I haven't played the game with used oil from that vehicle before.

Would love to have an MRV in the shed...alas I don't.

 

[wemay]

Thanks for sharing Shannow,

I would've been just as concerned with a more unusual consumption pattern. More so than the freezer test, no? How often do you see those temps and how often do we disuade others from relying on those youtube cold pour and one-armed-bandit tests.

 

[Shannow]

-20C is about 9C colder than I can get...but still 20C above the glug bottle tests, and 15C above where the 5W is MRVed at (like I said, I'd like one).

Wouldn't have drained it but for my reading as to the "promise" of miscibility, I lost faith in my original ideas, and the strange consumption pattern.

 

[wemay]

Understandable in light of the information found in the ASTM D6922 papers.

 

[Garak]

Originally Posted By: wemay
How often do you see those temps and how often do we disuade others from relying on those youtube cold pour and one-armed-bandit tests.

I'd look at it this way, Wemay. Shannow has a pretty good climate, and that gives him a little more freedom to play with fewer consequences than some others might face. With respect to the general warning about backyard testing, this is just confirming what we already knew and is in no way trying to show that Brand X with special additive Y is better than everyone else. Basically, mixed oil may not flow or pour as well as a new, fully formulated motor oil.

As a side note, when I had my old LTD, which was always outside, I remember having to add some oil (5w-30 GTX) before a highway trip. I had neglected to bring a quart inside to warm up, and had it in the trunk. I had to squeeze the thing like a toothpaste tube, rather than pour it in like a regular person.

 

[Dallas69]

So it's ok for a select few on here to mix oil but a severe no-no for the rest of the common folks?
Well this explains alot.

 

[Shannow]

Originally Posted By: Dallas69
So it's ok for a select few on here to mix oil but a severe no-no for the rest of the common folks?
Well this explains alot.


Where did you get that ?

Read through all of my responses, I used to, I read about the issues, and got cold feet on the process when I found out what the miscibility standard ACTUALLY promised as opposed to what lore here said (it appears that I may have found some of them), and I advise against it, and ceased the practice personally.

So where's the back-up for your assertion ?

Mix to your heart's content, but as two actual formulators in this thread have said...you can't even guarantee that mixing two SN oils meets SN at the end.

If you wander the internet telling people "it's all OK, mix and you will have no problems, the API guarantees it", all you are doing is demonstrating your ignorance.

 

[Dallas69]

I read your post about your super brew.It sounds like you have made a mixture of different oils,have you not?

More power to you and mix away.

 

[fdcg27]

If one wants to mix different oils, then he should do so with full knowledge of the potential pitfalls.
The applicable API standard doesn't guarantee that mixed oils will perform well.
Far from it.
Based upon what I've learned in reading Shannow's posts in various threads concerning mixing, I'd probably avoid doing so in either colder weather or for a long OCI.
For a short OCI in warmer weather, there's likely no problem.
I might mix oils sometimes, simply as a matter of expediency.
If I have an odd quart of M1 laying around, it might get mixed with PP, for example.
This is a matter of convenience, not best practice.
If you've got a bunch of odd quarts laying around that you just want to get rid of, then you might mix them.
Just be aware that the blend may not meet any of the claimed standards of its constituent oils and may have cold performance inferior to what any of the oils would have had on its own.
Knowledge doesn't preclude a practice, it merely informs it.

 

[wemay]

Hi Dallas69,

Yes: he used to mix.
He has since come across what the API and ASTM testing say about miscibility and changed his mind. In the process of doing so, he has shared the information with all of us and gone the extra step of explaining it. If people didn't know the background, yes, it could seem hypocritical but it definitely is not when all the information is known.

 

[wemay]

Originally Posted By: Garak
...I had to squeeze the thing like a toothpaste tube, rather than pour it in like a regular person.

I couldn't even imagine being that cold

 

[Garak]

Originally Posted By: Dallas69
So it's ok for a select few on here to mix oil but a severe no-no for the rest of the common folks? Well this explains alot.

Well, you can interpret what I said as you like, but that's not exactly my point. In certain cases, the oil company says to mix away (i.e. Red Line). That's a separate issue. What I meant, and have stated before, is that if one is mixing, one had better be cautious at the extremes. Mobil 1 EP and Amsoil SS don't give you a 20,000 mile oil guarantee. And, I'm not going to try to mix two different 0w-XX oils in a snap of -40 weather in this province and see how well it goes at startup. On the other hand, I'm not too worried about my lawnmower that requires any basic, modern API oil of some sensible viscosity and never has anything approaching a real cold start.

No one said severe no-no, either, be it for the "common folks" or a "select few." There are pitfalls, that's all. Personally, I never mix oils. That's just me.

 

[fdcg27]

What are you saying, Garak?
I mean, if Amsoil says that SSO is good for 25K and XOM says that M1 EP is good for 15K, then by mixing them 1:1, you'd have a 40K oil!
Surely this must be correct?

 

[Trajan]

Originally Posted By: OVERKILL
Originally Posted By: fdcg27
I guess it just bothers me a bit that the OP asked a serious question and got many answers, one from a very thoughtful and bright member who has debunked the common perception of the API compatability standard in a number of threads and who has also provided links to actual lab results indicating that the interaction between VIIs could result in a much thicker oil at start-up temperatures than any casual blender might anticipate.
Instead of having most of us sit back and realize that we hadn't considered either, we still have a bunch of members telling the OP to mix away with no concerns.
Kind of makes you wonder whether folks bother to read threads before they post in them, or whether they can read critically at all.
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.


Amen.

Shannow's posts on this subject have been extensive and detailed. Yet every time it is brought up, instead of the potential caveats associated with such an endeavour being discussed in earnest and the fact that it SHOULD be OK "but...." being the theme of the subject we have folks completely dismissing the technical aspect of the process and instead advocating that "home chemist: the oil game" brings with it "no issues", tossing out anecdotes as proof of their mantra, seemingly oblivious to what Shannow posts on the subject.

And this happens EVERY TIME

+1

 

[wemay]

Originally Posted By: Trajan
Originally Posted By: OVERKILL
Originally Posted By: fdcg27
I guess it just bothers me a bit that the OP asked a serious question and got many answers, one from a very thoughtful and bright member who has debunked the common perception of the API compatability standard in a number of threads and who has also provided links to actual lab results indicating that the interaction between VIIs could result in a much thicker oil at start-up temperatures than any casual blender might anticipate.
Instead of having most of us sit back and realize that we hadn't considered either, we still have a bunch of members telling the OP to mix away with no concerns.
Kind of makes you wonder whether folks bother to read threads before they post in them, or whether they can read critically at all.
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.


Amen.

Shannow's posts on this subject have been extensive and detailed. Yet every time it is brought up, instead of the potential caveats associated with such an endeavour being discussed in earnest and the fact that it SHOULD be OK "but...." being the theme of the subject we have folks completely dismissing the technical aspect of the process and instead advocating that "home chemist: the oil game" brings with it "no issues", tossing out anecdotes as proof of their mantra, seemingly oblivious to what Shannow posts on the subject.

And this happens EVERY TIME

+1


Bulls Eye!

 

[Garak]

Originally Posted By: fdcg27
What are you saying, Garak?
I mean, if Amsoil says that SSO is good for 25K and XOM says that M1 EP is good for 15K, then by mixing them 1:1, you'd have a 40K oil!
Surely this must be correct?

Yep, you are absolutely correct. I averaged when I should have added.

 

[Shannow]

Originally Posted By: Dallas69
I read your post about your super brew.It sounds like you have made a mixture of different oils,have you not?

More power to you and mix away.


We're getting places. Reading's not your issue, comprehension is.