yes, this is indeed a "greasy" question ;)
All oils go thinner when they get hot. A 10w30 oil will have the viscocity of
a 10w oil when cold. When hot however, the viscocity will not drop as rapidly
as a 10w oil. Istead, at 210F, it will maintain viscocity similar to a 30 w
oil AT THAT temperature. The oil is still thinner than room temperature.
There have been numerous discussion on synthetics. Look at the archieves.
D^2
Quoting Daniel M Wing <imp1983@xxxxxxxx>:
> Hi,
>
> I have an oil question, and you can reply privately if you want.
>
> I know that 30w oil is recommended by most for an older engine,
> and race engines use it too.
>
> But, what is not so good about using multi- viscosity oil?
>
> Isn't it supposed to change with the temperature? When the
> engine is cold, it is thinner so that it is easier to start and get it
> pumping. But, when it's hot, doesn't the viscosity go up, making
> it in effect 'thicker'? (Try starting your car at -10 degrees F and
> tell me 30w is better.)
>
> Also, I have always thought that synthetic oils are supposed to be
> far superior to other oils, because it doesn't break down as fast,
> and it clings to the engine parts longer, providing better lubrication
> at initial startup. Or, is this a bunch of hype?
>
> Just curious. No oil wars please (unless in the mid east).
>
> Dan Wing
> Marcy, NY USA
>
> imp1983@xxxxxxxx
>
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