Originally Posted By: The Critic
Originally Posted By: fdcg27
Why do you want to do this?
Why would one as anal as you are about caring for your car want to run a blend of oils with a completely unknown set of properties?
You don't know what grade you'll end up with and you don't know whether the blend will meet any reasonably current API spec.
I'd put this witch's brew in an old beater or use it for top-offs.
I would probably avoid putting it in any engine I cared much about.
Having written all of the above, I'm pretty sure that no mix of oils in the climate in which you live would do any harm.
You could probably use a mix of oils for the rest of the car's useful life and you might reduce the life of the Prius's engine by as much as two or three hundred miles.
You might also end up with some varnish, but you'll probably see that eventually anyway.
I'm trying to not be wasteful. Trust me, I gave this some serious thought.
But here's the mix that I ultimately ended up with:
0.6 qt Valvoline SynPower 0w-20
0.6 qt QS Ultimate Durability 0w-20
1.75 qt Toyota Synthetic 0w-20
0.5 qt Mobil 1 Extended Performance 0w-20
1 qt SuperTech Synthetic 5w-20
I can't say that I'm completely proud of running such a cocktail, but I am also proud of not wasting.
I will run it for 5,000 miles and then drain it for something more normal.
Their all synthetic, 0w-20 except 1 5w, all meet API, I don't see an issue. With the Valvoline, you'll add some sodium, and with the M1 you'll add some magnesium to the mix. Should be fine.