is it ok to mix synthetic oils?

Time to change oil. I used mobile 1 5w-30 last time, this time got mobile 1 0w-20. One gallon is not enough to totally fill, can i top off with leftover 5w-30 or should i not mix the two?
Thanks!

 

You should never mix different oil weights...

 

Most state it is not an issue to mix synthetic with dino oil of the same weight.
Some say mixing different weights may not allow the oil to mix and may separate when the engine is off.
I would be more concerned of using a weight oil not specified for the engine.
imo, spend the extra money and use the same weight and kind of oil.

 

Above all, I'd be more concerned with not having enough oil. If I were in the middle of nowhere and needed oil, and the only thing I could find was something not spec'd for my engine, I'd run it.

But as others have stated, run the weight that Toyota calls for. That viscosity is spec'd for a reason.

And if you've already got synthetic in there, top it up with more synthetic for best results from that brand of oil.

 

If it was the other way around and a top-off with 0w-20 wouldn't hesitate at all. But since you don't have the correct oil spec as it is, get the correct weight 5w-30.

 

At the risk of sounding like another self anointed forum expert - the simple answer is; yes you can mix the two synthetics - do a google search! Consider, in the modern internal combustion engine, up to half a quart of motor oil remains in the engine after an oil change (oil galleries, sump, etc) unless you refill with EXACTLY the same oil you changed, a naturally occurring mix occurs with no adverse effects.

 

https://mobiloil.com/en/search?q=mixing oils

 

I have done it a few times when I lived in the country and was 30 min from an auto store, nothing bad happened. Truck has 225,000 miles on it.

 

Well, the manual calls for 0w-20, which I could not find last time but i still wanted to go synthetic so thats why I used 5w-30. This time while in the store they had 0w-20 and I could not recall which one I had gotten last time so i got it. If it's a problem to mix weights I'll get more of each and just switch up but use the same weight per fill. I switched from dino oil to synthetic last change and it didn't seem to be a problem. That was the first change since buying the truck and I have no idea what type or weight the dealer had put in.
Thanks for the answers!