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 > > ________________________________________________________________ > The best thing to hit the internet in years - Juno SpeedBand! > Surf the web up to FIVE TIMES FASTER! > Only $14.95/ month - visit www.juno.com to sign up today! > >