Originally Posted by
ZERACER
I agree with wanting to suspend the contaminants by running the engine until warm however my understanding about multi viscosity oil is, it is thinner when cold "0" and thicker when hot "40"? In the old days with straight 20, 30 or 40 weight it would get thinner when hot. That is why multi viscosity was developed.
Your statement above is probably how most folks view a multi-grade oil. My dad did, for one. Actually, the multi-grade oil rating is an oil that has the properties of the lower weight oil in winter conditions (to provide improved engine protection) and the properties of the higher weight oil under normal operating conditions (to provide improved engine protection). Normal operating conditions for most cars is around 210F-220F, with proper cooling system functionality. That being said, it's an oil that has a "flatter" viscosity profile as operating temperature increases.
Dating myself somewhat, I remember "the good old days" when my dad ran a 30W oil during summer & a 20W oil during winter.
The video is really good!