I have some leftover Pennzoil Plat full synthetic 5-20W. I added a qt on top of 5 qts Mobil 1 EP 0-20W to my 2020 Lexus ES 350. Are the base oils and additive packages compatible? Thanks.
Mixing Brands
- Thread starter artbuc
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Not necessarily compatible but it is miscible. IMO and based on advice from others way more knowledgeable in this thread below, don’t go out of your way to erroneously mix however topping off or mixing from brand swapping is fine. It isn’t that it will harm your engine. It’s that the mixture of the two products will very likely not be as good as the individual products unto themselves. You’re buying a top tier product and then likely creating a lesser product inadvertently.
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BrendanC
$100 site donor 2024
i wouldn’t purposely mix. the only thing i will do is top off with a different oil from the same manufacturer if the same oil cannot be easily located.
So I'll ask, why not?
Mixing different chemistries can have adverse effects on the performance on either or all mixed. You are playing a guessing game. To me not worth it. I am not a chemist, but have read a bunch on this topic, and have come to the conclusion that while sometimes fine, it is not a habit I would settle into.
You are buying an oil, that has been certified, all by itself, with nothing else. Just because the engine does not blow up in 3000 miles does not make it a success.
Dead Horse being beated again
maybe not so dead
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Won’t make a difference. Project farm ran a UOA after running a brew of like 5+ different oils and weights and everything was fine
And a Blackstone UOA at that.
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Is that supposed to give us more confidence or less?
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Engine didn’t blow up, wear levels were fine, id be cool as a cucumber seeing that report
But lots of oil remains inside and engine at oil change.
So unless you never switch oil brands, types, weights, its mixed. Some people change oil type nearly every oil change. There could be a dozen different oils in their engines.
They don't seem to ever have any issues.
When I was young, I just bought whatever was on sale, drove high mileage used cars, zero issues.
My Honda Prelude had so many different oils in it, even I wasn't sure anymore what strange brew it had.
So did my grandfather in his Ford F150, whatever was cheapest.
Just my observations.
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which means nothing
Good info, thanks. I won’t mix again but will let this one ride. Local Wally was out of my usual PP 0W20 so I got M1. I drive about 4K miles per year so I will accept less than optimum oil performance over the next year.
Reading the responses here plus other internet articles, I wonder why Toyota and other manufacturers do not prohibit or at least warn against mixing brands? They do warn against using incorrect weight but not mixing brands.
Reading the responses here plus other internet articles, I wonder why Toyota and other manufacturers do not prohibit or at least warn against mixing brands? They do warn against using incorrect weight but not mixing brands.
OVERKILL
$100 Site Donor 2021
So he contacted Savant and had them run his home brew through the SAE sequences and it passed them all?
Oh wait, no, I see here you indicated that he just ran a test whose purpose is to determine if the oil is suitable for continued service (contamination levels are below limits, TBN and TAN are still acceptable) and not actually a performance test for the lubricant at all. What a shame!
having residual oil in the sump is one thing....meaningfully mixing brands is another.
Patman
Staff member
Exactly! We have people here who have been mixing different brands on purpose for years and think that they are making a better oil. News flash: they’re not!
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