What should I do with "extra" oil?

[kschachn]

The only thing an API license or otherwise passing ASTM D6922 gets you is miscibility. It does not guarantee to retain any license, specification nor approval any of the mixed oils may have. Nor does it guarantee the winter rating is retained.

It won’t cause damage is all it guarantees.

 

[Astro14]

The only thing an API license or otherwise passing ASTM D6922 gets you is miscibility. It does not guarantee to retain any license, specification nor approval any of the mixed oils may have. Nor does it guarantee the winter rating is retained.

It won’t cause damage is all it guarantees.

Exactly, miscible means that it will not cause damage to mix the oils.

But, some additives do not “play well“ with others. So when you mix oils, there is a chance that you will degrade the performance of those additives, and the oil will no longer meet specifications.

You, as a consumer, have no way to know if that happened. You would need a lab. I prefer not to use my engine as a lab, so I avoid mixing.

 

[oil pan 4]

All my small engines LOVE the left over good stuff.

riding mower, push mower, tiller, backpack blower, portable gensets.

I leave the 20 out of any mixes and keep all the air cooled stuff to 30 something and above standardizing on 0W-40 when filling from scratch.

I have an oil cap temperature gauge, in line mechanical or just test the temperature when I dump the oil as it comes out and go based on temperature.
The woodchipper and stump grinder only hit a max of around 180f so they get an oil that ends in 30. The pressure washer and riding mower are hitting more like 280f so they get oil that ends with 50.
The air compressor and log splitter engines hits 230f or so only when using the sand blaster or splitting knots so I put an oil that ends in 40 in those.
My legion of push mowers get a 40 or 50 oil, whatever I have open at that moment. If they need a little oil they get whatever I can lay my hand on first as long as it's not gear or thread cutting oil.

 

[oil pan 4]

The only thing an API license or otherwise passing ASTM D6922 gets you is miscibility. It does not guarantee to retain any license, specification nor approval any of the mixed oils may have. Nor does it guarantee the winter rating is retained.

It won’t cause damage is all it guarantees.

Yeah it's summer and he's talking about mixing a 5w and a 10w so probably not a problem.

 

[kschachn]

Yeah it's summer and he's talking about mixing a 5w and a 10w so probably not a problem.

Well then you are good to go if you don't care about the rest.

 

[oil pan 4]

Well then you are good to go if you don't care about the rest.

I wouldn't worry about it.

 

[Triple_Se7en]

Nothing will happen. Been doing it with multiple brands for almost a half-century. I've had engines go over 300k mixing oils. It's only recommended to use same brand name, not knowing your driving style or maintenance programs.

 

[Bill7]

I'm going to be getting a 2019 Kia Sportage (2.4l) someday this week, after its been through service. It has 98k miles and looks to be in really good shape.

I'm going to change the oil to Valvoline Restore and Protect 5W30. But I have this jug of Quaker State 5W40 Euro Oil and I was wondering what's the best thing to do with it? It's a 5 qt system and I believe the jug has just under 4qts, so not enough for a full fill. I'm conflicted on what to do with it.

- Mix it with the Valvoline? 20/80, Or 50/50, perhaps?
- Use it as a top off?
- Something else?

I myself am leaning towards mixing the two, using the Euro oil like an additive. But what does BITOG think? Y'all are smarter than me

I prefer to always get rid of the least desirable (either oldest oil, cheapest oil, non strategic brand oil, etc) oil first, so in your case,
I would use use all of the Quaker State 5W-40 oil first, adding 4 quarts of the Quaker State and 1 quart of any low priced full synthetic you might have laying around, and then the 2nd oil change use the 5 quarts of Valvoline Restore and Protect.

 

[burbguy82]

But, some additives do not “play well“ with others. So when you mix oils, there is a chance that you will degrade the performance of those additives, and the oil will no longer meet specifications.

This is why mixing should not be done on a regular basis.

It won’t cause damage is all it guarantees.

If you mix oils together that are not "playing well" with each other, will the oil work for the proper amount of time, or will it degrade at 1500 miles, and all the while 6000 miles later..........."no damage".

 

[TomYoung]

If I mix oils - and I don’t any more - I would stick with the same family, e.g. Mobil mixed with Mobil, QS mixed with QS, so that the additive chemistry is the same.

All oils are miscible. That is they can be mixed without harm.

But nobody guarantees the performance of the additives when you do so.

If it were me, I would buy another quart of the Quaker State 5W40 Euro - change the oil, no mixing.

Or take that jug, pour it in the recycling at the auto parts store and move on. We are talking about $20 of oil here, not a million dollar decision.

Oh, that’s where you are so wrong. These are the decisions that haunt us day and night. What does one do with oil than does not quite fit into current plans. That is the definition of a “million dollar” decision. Also, recycling good new oil will never, ever fly among 99.99999% of Bitog folk.

 

[doublebase]

Well, I wouldn’t throw it away. You’ll find something to use it for at some point…lawnmower? Snowblower?

Personally I’d just top up with it, chances are that 2.4L is going to be burning through some good amounts of oil (unfortunately).

 

[Astro14]

Oh, that’s where you are so wrong. These are the decisions that haunt us day and night. What does one do with oil than does not quite fit into current plans. That is the definition of a “million dollar” decision. Also, recycling good new oil will never, ever fly among 99.99999% of Bitog folk.

Wrong, how? About the potential for “additive conflict”? I’ve discussed that with folks who formulate oil.

Wrong about pouring oil in the recycling bin?

Well, if I had OPE that used oil, I would run it in my tractor, or mower, snowblower, or whatever.

But, I don’t. All my OPE runs on Makita batteries. So, if I have no use for a thing, then why keep it?

That’s why I said, “if it were me” - and I meant it. I would buy another quart to match.

Or dump it.

 

[TomYoung]

Wrong, how? About the potential for “additive conflict”? I’ve discussed that with folks who formulate oil.

Wrong about pouring oil in the recycling bin?

Well, if I had OPE that used oil, I would run it in my tractor, or mower, or whatever.

But, I don’t. All my OPE runs on Makita batteries. So, if I have no use for a thing, then why keep it?

That’s why I said, “if it were me” - and I meant it. I would buy another quart to match.

Or dump it.

What about the good feelings from simply having oil on your shelf? I didn’t mean any offense. I prefer not to mix oils, but have never actually heard a person show damage from additive conflict.

 

[Astro14]

What about the good feelings from simply having oil on your shelf? I didn’t mean any offense. I prefer not to mix oils, but have never actually heard a person show damage from additive conflict.

“Show damage” in an engine - me, neither.

But lab testing has shown that some additives are incompatible. That’s enough for me. Damage in an engine, as the result of excess foaming, or other deleterious effects of mixing, might take a while to manifest. Not going to take the chance, personally.

I am just not a “frankenbrew” guy. I know that makes me odd among this crowd, but I was putting oil in engines long before any specification required miscibility, and I avoiding mixing brands back then, if I could. That habit has not left.

If I had a use for a couple of quarts of odd oil, I would keep it. I have a shop full of stuff that I keep, because it might come in handy, and gets lots of “good feeling” from all that stuff, but at some point, a jug of oil that I can’t use is just taking up space.

I realize, as well, that when I change brands in an engine, that there is a small amount of the old brand in there, but it’s less than a quart, and the additives are somewhat used up at that point, so, it’s a much smaller effect than a 20% mix like the OP was considering.

Besides, dumping that jug of oil, costs, what, the same as 4 coffees at my local boutique? Hardly an impact on my budget.

Or my life.

 

[burbguy82]

What about the good feelings from simply having oil on your shelf? I didn’t mean any offense. I prefer not to mix oils, but have never actually heard a person show damage from additive conflict.

You never hear a bad review of the fall from a suicide jumper either.

 

[cptbarkey]

Have been mercilessly mixing salad oils for some time with no engine exploding yet. Oldest first. The most recent change I did was marrying about half Castrol with Valvoline. I can see the marketing teams throwing darts at each other right now in the sump. My supply is soon to be less DEI so mixing may become less of an option, but I really hate seeing 1.7 quarts of something sitting on a shelf. OCD I guess. I'm willfully blind to what might be happening, but I'm also doing short OCIs because I can afford to and I'm bored.

 

[E150GT]

I would use it in the lawnmower Personally.
I've mixed oils before in my truck. Still runs today

 

[oil pan 4]

I would use it in the lawnmower Personally.
I've mixed oils before in my truck. Still runs today

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I did an experiment when I worked at an auto parts store. I took a bunch of disguarded oil jugs, tipped them up to let them drip into a 1 gallon jug. After a week or so the first 1 gallon was nearly fully. Only did it to test the old wives tale that you can't mix oil.
So a mix of every weight, every brand the store sold and then some went into my riding lawnmower. That lawnmower ran like that for years till I sold it.
Mixing different motor oils doesn't appear to do anything bad.

 

[TomYoung]

You never hear a bad review of the fall from a suicide jumper either.

Those few who survive uniformly talk about realizing their mistake on the way down!

 

[kschachn]

I did an experiment when I worked at an auto parts store. I took a bunch of disguarded oil jugs, tipped them up to let them drip into a 1 gallon jug. After a week or so the first 1 gallon was nearly fully. Only did it to test the old wives tale that you can't mix oil.
So a mix of every weight, every brand the store sold and then some went into my riding lawnmower. That lawnmower ran like that for years till I sold it.
Mixing different motor oils doesn't appear to do anything bad.

Yes it’s an “old wive’s tale”. As noted already in this thread, any oil that passes ASTM D6922 (also part of an API license) will be miscible. But that’s all it guarantees.

Plus ASTM D6922 is a bit more rigorous than your auto parts store test.