Oil pressure question...I promise it's not another "who likes what' thread!

So any oil that is single grade (not “weight”) like an SAE 30 will always be less viscous at ambient temperature (what ever we say the ambient is...say...50 degrees) than it is a 212 degrees.

A multi grade oil (just say 5w50) will gain viscosity with temperature.

Click to expand...

Sorry, but that is just not true. ALL motor oils become thinner (less viscous) with INCREASING temperature.
The multi-grade ones will not thin out AS MUCH as a single-grade but they will all become less viscous. The 5W-50 becomes as thin as a straight 50 would when hot, but it's still thinner than when it's cold.

Just google "oil viscosity chart" and you will see that every single one has a negative slope (viscosity drops with increasing temperature).