<VV> <WW> Oil Viscosity

[Jim Simpson]

0W-30 oil does not have "zero" viscosity, rather the 0W refers to how the
oil acts at low temperatures.  (The "W" means winter.)

Here's a good reference:
https://www.bobistheoilguy.com/putting-the-simple-back-into-viscosity/

Scroll down to the tables and you will see that "0W" oil has a viscosity of
3250 centipoise at -30 deg. C.

The 0 (zero) refers to oil "weight", an old term that has essentially lost
its meaning over time but is still used in the oil industry to describe
lubricants.  I've never found a good source that describes where the term
came from, but the SAE has come up with definitions for what the various
"weight" oils are in terms of viscosity at various temperatures.

Jim Simpson
Group Corvair