ok what does the first number mean ? and second ??

exampole, what would u use in a illinois climate and rebuilt D series motor ? can someone explain what the first and second # means ?

i cam from different country and we had different #'s thanks

 

5w-30: 5 (w)eight is as thin as the oil will get at operating temp, 30 (w)eight is as thick as it will get when cold (basically).

This is known as a "multi-viscosity" oil, and 5w-30 is an SAE (Society of Automotive Engineers) rating for engine oil.


I use 5w-30 year round, most certainly in the winter.

 

so 5w-30 would be good in syntetic. ?