0W16 + 0W20 = 0W18? Mixing 2 qts Castrol 0W20 with 2 qts Toyota 0W16!

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My car is a 2020 Honda Accord Hybrid. I bought it brand new last year and next month (October 2021) would make it 1 year of me owning it. Car has 34,500 miles as of today.

Honda specified the car uses 0W20. I have done 2 oil changes and sent samples to Blackstone Laboratory. UOA posted here.

For the third oil change, I had some leftover oil of different weights that I almost threw away by taking to dump at AutoZone, but I changed my mind. I decided to use the oil to cycle in my engine and rinse or say wash the engine and dump.

So, I did my oil change with a mixture of; (picture below)
- 1/2 quart M1 0W20 EP High Mileage
- 1/2 M1 0W20 EP
- 1 quart M1 5W20 Annual Performance
- 3 quarts of 5W30 Shell Rotella Gas Truck.
nJx5uz7.jpg


I mixed all that and it made 5 quarts of oil.I put 4 quarts in my car. My hope was to drive it for 6,000 miles and dump it. But, I just realized this combo has dropped my MPG. I like to hypermile and now I can barely get my car to get 60mpg and above.

Here is my data since my oil change. You see I am only in the low 50s. But when I hypermile, I often get upper 50s or low 60s. Picture of my recent mpg numbers after each fill up since my oil change.
UM3jBmI.jpg


So, I have concluded that the current mixture in my car may be too thick and has caused my mpg to drop. Hence, I may dump this oil at around 2,000 or 3,000 miles of use after it has circulated well enough to "rinse" the engine.

After playing in my mind with the thought of mixing oils, I decided I wanted to try the 0W16, which is NOT specified for my 2020 Honda Accord Hybrid.

After a small research, I found out the Toyota 0W16 is made by Mobil 1 and has a good additive package. I went and bought 2 quarts from the dealership today.
W5lXH6j.jpg

I plan to do an oil change with;
- 2 quarts of Toyota 0W16
- 2 quarts of Castrol Edge HM 0W20
dJU7kWW.jpg

jvSyHjf.jpg


So, a funny thought crossed my mind that maybe 0W16+0W20=0W18?

I really plan to do this to see what will happen. I doubt it will do any harm to my car for one oil change of maybe about 7,000 miles to maybe 10,000 miles. I want to see if this will make any noticeable difference like improve gas mileage or car idles smoother or smoother acceleration. Let me just say any slight thing that my mind tricks me into thinking it is a noticeable improvement that was not there before. But I hope it still protects my car.

If the combo bothers me, I will drain and put only my required 0W20.

What are your thoughts?
 
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PetitFrereArmada

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I don't understand dumping $25+ in oil at 2,000 miles to save a couple bucks in gas.
The oil was leftover oil from a few oil changes and most of it is not the recommended 0W20 that Honda recommends for my car.

So, my first thought was to take it to AutoZone and dump it there. Especially as I have had the oldest leftover oil for about a year now.

I used the mixed oil only because I thought instead of going to dump it, why don't I just use it to "rinse" my engine, LOL. I wish to drian the oil before it gets dark. That is why I am thinking maybe I should dump the oil between 2,000 and 3,000 miles. It was leftover oil that should have been dumped anyway, but I was always just keeping them over time.

My car has had 2 oil changes since I bought it brand new. The oil changes were done with 0W20 that I bought $14 (Mobil 1 EP and Mobil 1 EP High Mikeage) for 5 quarts, after $10 rebate.

All the 5 gallons of Castrol that I currently bought come with a $10 mail in rebate. So, ends up being about $15 for 5 quarts.

So, I do get my oils for pretty good prices, except the Toyota 0W16 oil that I went and got it from the dealership at $7.62 plus tax a quart. I called 4 dealerships around me and all were asking me for $9.99 and 10.99 plus tax. But the closest dealership to me said $7.62 plus tax. I went and bought 2. For the only purpose of mixing up with 2 quarts of Castrol to see what will happen.

I can always dump it any time if I feel I do not like how my car is reacting to the combo oil in it. But I believe it will be very ok.

So, I still have like 2,500 miles to go before I dump this mixed up oil now, except I suddenly change my mind someday sooner and just dump it to put the 0W16/0W20 combo in my car.
 
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The oil was leftover oil from a few oil changes and most of it is not the recommended 0W20 that Honda recommends for my car.

So, my first thought was to take it to AutoZone and dump it there. Especially as I have had the oldest leftover oil for about a year now.

I used the mixed oil only because I thought instead of going to dump it, why don't I just use it to "rinse" my engine, LOL. I wish to drian the oil before it gets dark. That is why I am thinking maybe I should dump the oil between 2,000 and 3,000 miles. It was leftover oil that should have been dumped anyway, but I was always just keeping them over time.

My car has had 2 oil changes since I bought it brand new. The oil changes were done with 0W20 that I bought $14 (Mobil 1 EP and Mobil 1 EP High Mikeage) for 5 quarts, after $10 rebate.

All the 5 gallons of Castrol that I currently bought come with a $10 mail in rebate. So, ends up being about $15 for 5 quarts.

So, I do get my oils for pretty good prices, except the Toyota 0W16 oil that I went and got it from the dealership at $7.62 plus tax a quart. I called 4 dealerships around me and all were asking me for $9.99 and 10.99 plus tax. But the closest dealership to me said $7.62 plus tax. I went and bought 2. For the only purpose of mixing up with 2 quarts of Castrol to see what will happen.

I can always dump it any time if I feel I do not like how my car is reacting to the combo oil in it. But I believe it will be very ok.

So, I still have like 2,500 miles to go before I dump this mixed up oil now, except I suddenly change my mind someday sooner and just dump it to put the 0W16/0W20 combo in my car.
I highly doing it will effect MPG by much.
 

PetitFrereArmada

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Why make things complicated? Just stick with 0W20.
The thing is I have been intrigued by this new 0W16 weight. Especially when I found out Toyota is using in their Camry Hybrid for better mileage and better protection. Honda is using it in the Honda Fit. It is claimed 0W16 will be a lot more used and popular in the near future.

Same as when 0W20 came out, people did not trust it because it is too thin. But now 0W20 is recommended for almost every normal car even turbos, big V8 engines like the Infiniti QX and Nissan Armada and some very high performance cars.


So, I am thinking within 5 years, a lot more cars will be using 0W16.


So, I decided since the Camry Hybrid is using it, I am sure Honda will in the near future start using it in the Honda Hybrid. Till then, how about I try a combo of 0W16/0W20? So, I want to try and see if my engine will like it or not.

You know there are many threads on here of people mixing weights. So, it is nothing new about mixing weights. Also, I have never seen a thread where someone mixed weights and needed a new engine.


So, I hope I do this and have data to share. It would be great too if I end up sending a sample to Blackstone after I use this combo.


It would be a crazy combo. Imagine the oil I will drain which currently is a mixture of 0W20/5W20/5/30. Then I put in 0W16/0W20. So, there will be some little oil left from the last combo. Then add this new one. Now, it almost feels like a mixture of 0W16/0W20/5W20/5W30. I will definitely send a sample to Blackstone to do an analysis after I do use this 0W16/0W20 combo.
 
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The thing is I have been intrigued by this new 0W16 weight. Especially when I found out Toyota is using in their Camry Hybrid for better mileage and better protection. Honda is using in the Honda Fit. It is claimed 0W16 will be a lot mire used and popular in the near future.

Same as when 0W20 came out, people did not trust it because it is too thin. But now 0W20 is recommended for almost every normal car even turbos, big V8 engines like the Infiniti QX and Nissan Armada and some very high performance cars.


So, I am thinking within 5 years, a lot more cars will be using 0W16.


So, I decided since the Camry Hybrid is using it, I am sure Honda will in the near future start using it in the Honda Hybrid. Till then, how about I try a combo of 0W16/0W20? So, I want to try and see if my engine will like it or not.

You know there are many threads on here of people mixing weights. So, it is nothing new about mixing weights. Also, I have never seen a thread where someone mixed weights and needed a new engine.


So, I hope I do this and have data to share. It would be great too if I end up sending a sample to Blackstone after I use this combo.


It would be a crazy combo. Imagine the oil I will drain which currently is a mixture of 0W20/5W20/5/30. Then I put in 0W16/0W20. So, there will be some little oil left from the last combo. Then add this new one. Now, it almost feels like a mixture of 0W16/0W20/5W20/5W30. I will definitely send a sample to Blackstone to do an analysis after I do use this 0W16/0W20 combo.
It's ok to go thicker, but not what is below what manufacturer specs for.
 

PetitFrereArmada

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It's ok to go thicker, but not what is below what manufacturer specs for.
Sounds correct. But I am very intrigued and would like to try this combo. As long as I am not going to lose an engine, then I am fine. Which I doubt this will cause me to lose my engine.

At first, I wanted to do 1 quart of 0W16 and 3 quarts of 0W20. But I thought that would be too little of the 0W16 to see any effect.

So, I am looking forward to trying this 2 quarts 0W16 mixed with 2 quarts 0W20. After which, I will send a sample to Blackstone.

Well, this will be a while since I still have to use up this combo I currently have now in my car that is a thicker and that I am using to "rinse" my engine with.
 
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Many years ago I posted a similar question, about mixing oils of different brands and/or different types, here on BITOG. One of the old timers pointed out that there is a risk involved, that should be obvious to most of us here, but is easy to overlook.

Each motor oil is designed with it's own add pack, with different companies using different formulations for detergents and antiwear additives. Even within a brand, a HM oil may have a different add pack than an extended life motor oil.

Let's take your formula for an example. Castrol uses a heavy does of calcium and magnesium for detergents, and primarily phosphorus and zinc for antiwear. Toyota uses even a heavier dose of calcium, but also adds a good share of moly. Now that you mix them, the oil in your engine doesn't quite measure up in overall add pack to what either Castrol or Toyota engineered. This garage science experiment isn't going to protect your engine in quite the same way that either company intended.

This may be fine for a single oil change once in a while. But for one oil change after another, to never fully protect your engine, is risky.

You may reach out to Molykule and see if he still feels the same way.
 
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Many years ago I posted a similar question, about mixing oils of different brands and/or different types, here on BITOG. One of the old timers pointed out that there is a risk involved, that should be obvious to most of us here, but is easy to overlook.

Each motor oil is designed with it's own add pack, with different companies using different formulations for detergents and antiwear additives. Even within a brand, a HM oil may have a different add pack than an extended life motor oil.

Let's take your formula for an example. Castrol uses a heavy does of calcium and magnesium for detergents, and primarily phosphorus and zinc for antiwear. Toyota uses even a heavier dose of calcium, but also adds a good share of moly. Now that you mix them, the oil in your engine doesn't quite measure up in overall add pack to what either Castrol or Toyota engineered. This garage science experiment isn't going to protect your engine in quite the same way that either company intended.

This may be fine for a single oil change once in a while. But for one oil change after another, to never fully protect your engine, is risky.

You may reach out to Molykule and see if he still feels the same way.
Before I ran Redline D6 with my cocktail of 1.5 qt of Redline Racing and 1.5qt of Redline Racing low viscosity (Type F), as I like a nice strong shift with less slip. I checked with Redline that the add packs were compatible with mixing and they were. They don't advise it , but many many people do that with no issues they said. Expected corporate speak and a green light for me, and all has been well with my cocktailing.
 
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Before I ran Redline D6 with my cocktail of 1.5 qt of Redline Racing and 1.5qt of Redline Racing low viscosity (Type F

and all has been well with my cocktailing.

As long as the op changes oil relatively often (every 3500 miles) you can mix almost anything

It’s life and performance may be reduced however but if your not pushing an oci it shouldn’t matter

Myself I use up odds and ends on short oil changes, my one that looses oil gets random oils for top off.
 

PetitFrereArmada

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Let's take your formula for an example. Castrol uses a heavy does of calcium and magnesium for detergents, and primarily phosphorus and zinc for antiwear. Toyota uses even a heavier dose of calcium, but also adds a good share of moly. Now that you mix them, the oil in your engine doesn't quite measure up in overall add pack to what either Castrol or Toyota engineered. This garage science experiment isn't going to protect your engine in quite the same way that either company intended.

This may be fine for a single oil change once in a while. But for one oil change after another, to never fully protect your engine, is risky.
Yes, this will be my first time using this 0W16. I will do a UOA to see what Blackstone will say about it. I do not plan to do this all the time. I wish to try it this time and then see what the results would be from Blackstone. Given that this is a brand new car, I hope there will be no ill effect.

Mixing all these additives, I am thinking it should be ok. You know how some people buy oil because it has this one additive more than this other company's oil. So, how about we mix all those additive together to create a new breed of oil. While Toyota 0W16 offers a ton of Moly, I want to have tons of Moly for protection. Then I want a lot of magnesium, so Castrol would satisfy that urge.

This plan is to do this once and see what the UOA would say. Then decide if I wish to do it again or not. I am thinking I may run the oil (0W16/0W20) for atleast 7,000 miles before I do an oil change.

If you go to Mobil 1's website and see the 0W16 they have there, you see the only 2 vehicles they list are Honda Hybrid and Toyota Hybrid. Then they go further to say and any other car that specs for 0W16. So, that is one of the reasons that is making me want to try this. I was almost thinking of going all out and getting 4 quarts of Toyota 0W16, but I changed my mind and said let me start with a combo and see how things work out.
 

PetitFrereArmada

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0w16 is a very different animal than 0w20

Mixing these will have unpredictable results and the add packs may result in reduced oil life.
Yes, I want to find out about this unpredictable result. I wish to know what will happen to my own car when I use this. Results may vary for others. I would like to have some factual numbers and a report based on my own experience. As long as I do not lose an engine over this. But the car is still brand new. So, I doubt I will lose an engine over this combo.
 

PetitFrereArmada

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As long as the op changes oil relatively often (every 3500 miles) you can mix almost anything

It’s life and performance may be reduced however but if your not pushing an oci it shouldn’t matter
I agree with you. Something like 3,500 miles will probably not affect much. But I was hoping to do atleast 5,000, 7,000 or more close to10,000 miles before an oil change so that when I send a sample to Blackstone for a UOA, then I will be happy the oil did see some real use.

I do good with hypermiling and my Maintenance Minder has been going for almost 12,000 miles before needing me to do an oil change. I let my MM get to 0% before I do my oil change. My MM gets to 15% at around 10,000 miles.

Since I have a hybrid and I hypermile, my car is in electric mode some times where the engine is not used. For example, out of my 12,000 miles driven before an oil change, I can confidently guess that 3,000 of those miles were in EV mode where the engine was not working. So, that is why I feel ok going above 7,000 miles because atleast 1,500 of 7,000 will be on EV mode where the engine is not being worked.
 
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I think the change of season just a few days away, and a more than likely slight change in how the vehicle is driven will have more of an impact on fuel economy than the Frankenbrew you concocted.
 
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