Brand-specific question about mixing

[HawkeyeScott]

Mixing seems to be getting a lot of attention on here in recent days. So I'll pile on.

Going through my stash the other day, I happened on to 1 lonely quart of Valvoline 10w30 All Climate. It's SL oil, likely from an old purchase at a NAPA store.

How soon will the 4.0 in my wife's Jeep seize up if I was to mix the older oil with a 5-qt. jug of SM Valvoline, same viscosity?

OR, what if I bought 4 quarts of SM Valvoline 5W-20 and mixed in that gray-haired SL 10w30 for use in my 97 Crown Vic? (Both engines are at 100K.)

1 quart is obviously no big deal, but I would like to use it up. Oil is at home in an engine, not on the shelf. Help me send this oil home.

 

[Merkava_4]

I think you'll do fine with either plan, but why not just use the SL quart in the mower?

 

[HawkeyeScott]

Sorry Merk4. I should have mentioned that I had to sell the Snapper when I moved to a townhome a year ago. No chainsaw, beater, or oil stove to use it in either.

 

[Merkava_4]

That's alright

It's not a perfect world where everyone has a fresh green lawn.

You can mix it in just fine and it won't have much effect on viscosity either. It's not like mixing 5W-50 with 5W-20. . . .

 

[hominid7]

It would mix just fine, especially for beefing up your 5w20 valvoline for the summer months.

The last of the SL and the new SM Valvoline are not very different at all.

4 quarts valvoline 5w20 + 1 quart 10w30 = 6w22 oil (I think).

 

[Merkava_4]

It would still very much be a 20 weight.

All Climate 5W-20
45.9 cSt @ 40C
8.36 cSt @ 100C

All Climate 10w30
69.74 cSt @ 40C
10.67 cSt @ 100C

New Viscosity
5W-20 @ 80%
10W-30 @ 20%

49.9 cSt @ 40
8.8 cSt @ 100C

As you can see, it barely changed.

 

[Dave Hess]

Don't worry, mix that quart.

Why bother returning it for a different brand.