Mixing TGMO 0w20 and Castrol Euro 0w40!

FranklinJL · Feb 21, 2018

Couldn't resist the sale online of castrol 0w40. I tow a 21ft bassboat all over the southwest, running 75-80. I run a 2018 tundra 5.7 1794. Have always used 5w30 or 0w30. GC, or whatever mobil 1 was on sale. ?. How do I get something close to 30wt with 5 quarts of 0w40 and 0w20? I know mixing even doesnt always work.Thanks

FordBroncoVWJeta · Feb 21, 2018

2018 Tundra? That depends, would you like to keep your warranty in tact?

Triple_Se7en · Feb 21, 2018

Originally Posted By: FranklinJL

Couldn't resist the sale online of castrol 0w40. I tow a 21ft bassboat all over the southwest, running 75-80. I run a 2018 tundra 5.7 1794. Have always used 5w30 or 0w30. GC, or whatever mobil 1 was on sale. ?. How do I get something close to 30wt with 5 quarts of 0w40 and 0w20? I know mixing even doesnt always work.Thanks

Mix half and half for 0w-30 range. I've been home-blending for 25 years. Won't reduce your engine lifetime at all. Won't increase consumption or noise either. I am a first and last owner of all my vehicles. That's proof it works spendid.

OilUzer · Feb 21, 2018

it is not what you are asking but I learned today that 50/50 mix of xW-30 and yW-30 does not produce ((x+y)/2)W-30!

Originally Posted By: FordBroncoVWJeta

2018 Tundra? That depends, would you like to keep your warranty in tact?

not trying to hijack the thread but am curious about your Tundra. Have you always used something other than specified 0W-20? I have done a lot of research and it keeps leading me back to 0W-20. I was not comfortable with 0W-20 but it is growing on me ... lol With southwest temperatures, I assume 0W vs. 5W is not as much of an issue. you don't see cold temps like Alaska! but the 30 vs. 20 is what I am concerned about. I always wanted to use 5W-30 (vs. specified 0W-20) especially in the summer and if towing but haven't switched yet. at least not until the warranty is over. my research so far indicates that this engine likes 0W-20 and it is not just about fuel economy (CAFE). remember I said "so far", I am still working on it. Like to know what Toyota specifies for the same engine in hot climate outside US and if synthetic is not available and/or expensive in those countries ...

Hounds · Feb 21, 2018

JL, you're an intrepid man! Coming onto BITOG and even hinting about mixing oil weights much less brands! You, sir, are my hero. Now, WRT to what you're going to end up with, you can start here: http://www.widman.biz/English/Calculators/Mixtures.html. Sir Widman's work will give you a "good" (not perfect) idea of what you'll end up with. (Hint: 50%-50% will give you pretty much what you expect.) Oh, and you might wanna wrap your computer in a wet towel to prevent overheating when the High Priests of Miscibility are awakened. They don't take kindly to oil-mixers. Excellent choice on that Castrol 0w-40 weight, btw.

Shannow · Feb 21, 2018

meh...Arizona, you don't have to worry about two 0Ws making a 0W...

toneydoc · Feb 21, 2018

Mix it 50:50 and get on with the fishing

Smoqueed · Feb 21, 2018

Just pour the Castrol 0w40 in, it's close enough to a 30 weight anyways! Now if you're just trying to use old stock up, probably somewhere between 50-50 and 75(GC)-25(TGMO) would net you an actual 30 weight.

FlyNavyP3 · Feb 21, 2018

Sure you could do it, but why not just use the 0w40 straight? I would.

Patman · Feb 21, 2018

Originally Posted By: FlyNavyP3

Sure you could do it, but why not just use the 0w40 straight? I would.

And he can kiss the powertrain warranty goodbye too.

Virtus_Probi · Feb 21, 2018

The OPer says he tows a lot, is there anything about using thicker oils for severe service in the manual for the Tundra?

OilUzer · Feb 21, 2018

Originally Posted By: Virtus_Probi

The OPer says he tows a lot, is there anything about using thicker oils for severe service in the manual for the Tundra?

no, 0w-20 only!

dernp · Feb 21, 2018

5.7L Tundra? Bullet proof. Run whatever.

69GTX · Feb 21, 2018

Last I checked, the Castrol 0w-40 Euro is a lower calcium, higher magnesium brew. That's not easy to find in 20/30 grades unless you go to Mobil 1. Then you're mixing different oil base stocks too. Whatever you mix, you're either going to be altering the add pack, or the type of oil. Last I checked, the lower grades of Castrol are all non-magnesium, higher calcium. Though they do seem to alter these every few years. If you can find some older Castrol Edge 20 grade (pre-2016?) those are probably magnesium oils.

kschachn · Feb 21, 2018

Originally Posted By: 69GTX

Last I checked, the Castrol 0w-40 Euro is a lower calcium, higher magnesium brew. That's not easy to find in 20/30 grades unless you go to Mobil 1. Then you're mixing different oil base stocks too. Whatever you mix, you're either going to be altering the add pack, or the type of oil. Last I checked, the lower grades of Castrol are all non-magnesium, higher calcium. Though they do seem to alter these every few years. If you can find some older Castrol Edge 20 grade (pre-2016?) those are probably magnesium oils.

I've always thought that a far more serious potential of mixing is the loss of any certification, rather than some unknown ending viscosity.

lexus114 · Feb 21, 2018

why are some people so afraid of using the recommended oil? my nx is turbocharged and they still want 10k intervals on the 0w20..

FranklinJL · Feb 21, 2018

Because we know most 0w20 grades while perform well, are intended for fuel economy. In other parts of the world, most in hotter climates heavier oils are recommended. No way am I using 20w oil towing my boat at 80mph in the AZ desert when it's 110-115.

lexus114 · Feb 21, 2018

Originally Posted By: FranklinJL

Because we know most 0w20 grades while perform well, are intended for fuel economy. In other parts of the world, most in hotter climates heavier oils are recommended. No way am I using 20w oil towing my boat at 80mph in the AZ desert when it's 110-115.

i have not seen any evidence that proves what you are saying...just hearsay

kschachn · Feb 21, 2018

Originally Posted By: Patman

Originally Posted By: FlyNavyP3

Sure you could do it, but why not just use the 0w40 straight? I would.

And he can kiss the powertrain warranty goodbye too.

I've never seen a statement in any owner's manual, ever, that says using a grade other than the specified one(s) would void a warranty. Have you?

lexus114 · Feb 21, 2018

Originally Posted By: kschachn

Originally Posted By: Patman

Originally Posted By: FlyNavyP3

Sure you could do it, but why not just use the 0w40 straight? I would.

And he can kiss the powertrain warranty goodbye too.

I've never seen a statement in any owner's manual, ever, that says using a grade other than the specified one(s) would void a warranty. Have you?

if you have any sort of engine mechanical failure they may check to see what oil was used.

Mixing TGMO 0w20 and Castrol Euro 0w40!

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