When talking about oil 10W-30, 10W-40, ect...... What does the "W" stand for? I have always known or thought that it stood for Weight. Do different oil companys have a different meaning?


:beers:

The W stands for Winter. That means that the oil has the weight of 10 during winter start ups.

The break down of the name 10w-30 mean that it acts like a 10 weight oil when cold, but because of the oils chemical structure it changes to a 30 weight when hot. This way cars in cold climates will have a oil that will start thinner in colder climates, yet change to a 30 weight when the engine is wamer.

Yet they say as engine oil heats up it's viscosity is reduced........:confused:

Yet they say as engine oil heats up it's viscosity is reduced........:confused:




right?????????:confused:

right?????????:confused:

As I know oil loses viscosity as it heats up, so are you saying 10W-30 actually gets thicker when it warms up?

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

Interesting stuff... as the oil heats up, the coiled polymer chains straighten out, and prevent the oil from thinning like a straight weight would.

Yep, the 10w-30 means it acts like a thing 10 weight when cold, and a 30 weight when warm.