Motor Oil Info

[Mavrick]

10w30

I understand that 10w refers to the weight of the oil when cold, and 30 refers to the weight of the oil when warm..

But for the Xw.. is 5w thicker than 10w? Or 10w thicker than 5w?

Is it the same for the warm weight? or what?

I tried researching, but found a few completely opposite answers so i'm confused. Would appreciate a fairly simple but informing answer.

 

[87'GTstang]

The first one is viscosity basically. 0w is some thin stuff. If you were to put in to a comparrison, 0w would be like water and 20w would be like syrup. The second number is almost like a temperature rating. a formula such as 10w-20 would be better suited for cold weather and 10w-40 would be better suited for warmer weather. 30 is the weight that most people use because it is a good typical balance for all season.

*someone tell me if I have the weights backwards or not...........

 

[Daggar]

5w-30 indicates a 5 weight oil that performs like 30 weight when it's hot. Whereas 5 weight oil would perform just like you'd expect 5 weight to perform when it's hot. Metal expands when it heats up and requires better lubrication when hot. That's the reason for multiweight motor oil.


Edit: Here's a better description

http://auto.howstuffworks.com/question164.htm

 

[bdcardinal]

the number before the w is the weight of the oil when cold, 0C i believe. the "w" stands for winter. the second number is the weight of the oil at operating temperature. a 5w30 would be thinner when cold than a 10w30. however different oil manufactures 30 weight are slightly different. a lot of newer cars are supposed to run a 5w20 or a 5w30. the 4.6 motor for example wants 5w20 in applications in the US, however they use 20w50 in applications in Australia, and there are no differences in the motors.