this is kind of for my beater (cause the S is using whatever stated on the manual )

what are those? 5/30W? 10/30W? should older/high milage car use heavier weight oil? any good or bad? why?

thanks

 

The weight of the oil is just how thick it is. 10W-30 would be thicker than the 5W-30. The higher the number the thicker the oil.

 

The first number describes the cold start pumpability of the oil.

The last number describes how the oil behaves at temperature.

10W30 is just as thick/thin as 5W30 at operating temperature.

To get the 30 rating, conventional oil starts with a base of approximately 5 or 10, then special polymers thicken the oil at temperature to give it a rating of 30.

Therefore, one can conclude that a 5W30 has more non-lubricating polymer thickening agents than a 10W30, therefore potentially being less stable over a long period of time.

This is why I believe the S2000 is suggested to use 10W30.

Now synthetic can give cold pumpability and high temperature viscosity without all the additives. This is one of the reasons why I'm planning on using synthetic in the S.

 

SAE 10w30 this refers to the VISCOSITY (or resistance to flow aka thickness) of the oil as per specific tests laid down by the Society of American Engineers (this is where we the SAE bit) using a redwood viscosimeter (basically a jar with a calibrated hole in the bottom). the 10w means how thick the oil is at the lower temperature for the test ( w = winter or cold). 30 relates to how thick the oil is at the higher temperature.
as a full time grease monkey i recommend any fully synthetic oil suitable for high performance PETROL or GASOLINE engine to all my s2 customers.