5w20 + 10w40 = 7.5w30 ?

[KzMitch]

During December's $1/qt AutoZone sale last month I was able to buy some quarts of Valvoline MaxLife Synthetic Blend.
My truck calls for 5w30 (or 10w30).

If I mix 3 quarts 5w20 and 3 quarts 10w40, I get 6 quarts of 7.5w30, right?

I tried using a viscosity calculator online, but my iPad is too dumb for it.

Thanks

 

[horse123]

And why can't you just run what's recommended?

 

[Quattro Pete]

Originally Posted By: KzMitch
If I mix 3 quarts 5w20 and 3 quarts 10w40, I get 6 quarts of 7.5w30, right?

There is no such thing as 7.5w, so what you get is probably a 10w.

 

[KzMitch]

I can run whats recommended, and I have been.

But on my shelf in my garage is 5w20 and 10w40.
I just wanted to use what I had.

 

[WobblyElvis]

If you ask me, your calculations are correct and I would go ahead with it.

 

[KCJeep]

Your blend will work just fine. Actual results are a little unpredictable, calculator or not, but you'll likely get the perfomance of a 10w30 out of that.

Your blend certainly won't be overly thick with a full 50% 5w20 in there but I wouldn't expect stellar cold start performance in very cold weather (zero or colder).

 

[KzMitch]

Originally Posted By: KCJeep
Your blend will work just fine. Actual results are a little unpredictable, calculator or not, but you'll likely get the perfomance of a 10w30 out of that.

Your blend certainly won't be overly thick with a full 50% 5w20 in there but I wouldn't expect stellar cold start performance in very cold weather (zero or colder).


That's what I thought.
My Napa Gold Filters bought on sale will arrive after March 6.
OCI is right about then too.
And by March, Chicago temps are generally above 0.

 

[Doog]

I say blend away and let us know what happens. Frankenblends are cool. I do it all the time with the orphan bottles of oil on my shelf but mostly with 5w20 and 5w30.

Never an issue.

 

[danthaman1980]

As has been stated, you'll probably end up with a 10w30. Should be just fine for a summer run, unless you have a warranty to worry about.

 

[A_Harman]

50/50 blend of Valvoline MaxLife 5w20 and 10w40 gives 11.37 cSt at 100C. Definitely a 30-weight. Like others have said, cold flow characteristics probably of a 10W. You're mixing the same brand of oil, so there shouldn't be any problem.

 

[MalfunctionProne]

Originally Posted By: KzMitch
I can run whats recommended, and I have been.

But on my shelf in my garage is 5w20 and 10w40.
I just wanted to use what I had.


Do It.