5W30 lower pour point than 5W20?

[Audioquest]

I've been noticing that in some conventional oils, the 5W30 has a lower pour point than the comparable 5W30. For example, notice that Peak 5W30 pours at -39, whereas the 5W20 pours at -33. Isn't one of the benefits of the thinner 5W20 better startup protection in cold weather?

Peak

 

[mechtech2]

Note that there are TWO numbers in the oil's labeled specs.
The first is the cold performance, and the second the hot.
There is a RANGE, not an exact viscosity/thickness for each rating.
So events like you see do occur. What are apparent anomalies are withing normal limits.

Even odder is some Mobil 1 10w30 flowing better cold than Mobil 1 5w30!

 

[bepperb]

Consider that water is thinner than oil... oh... until you get to the pour point thing.

Viscosity and pour point aren't as closely related as it may seem.... all the more obvious by your observation.

Oil can have a pour point depressant added that seems to have little effect on viscosity. See Mobil 1 Truck and SUV for an example of that.