# Oil... how does it work? \[split\] **URL:** \ **Category:** Shift518 Off Topic\ **Created:** [January 6, 2012, 11:40pm UTC](https://forums.speedlife.net/t/oil-how-does-it-work-split/262189 "2012-01-06T23:40:40Z")\ **Posts on this page:** 1\ **Showing post:** 198
**Author:** ![Vovchandr](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/vovchandr/32/6275_2.png) [@Vovchandr](https://forums.speedlife.net/u/Vovchandr)\ **Post date:** [January 11, 2012, 8:02pm UTC](https://forums.speedlife.net/t/oil-how-does-it-work-split/262189/198 "2012-01-11T20:02:40Z")
> [@WTH: alignment at home](https://forums.speedlife.net/t/wth-alignment-at-home/47818/21): > > You can’t compare them to each other when on the same bottle (which you’re trying to do), but you can compare the non W number and the W number on the same bottle to the SAE scale- > > Again, for the 10000th time, 5w30 oil flows like a SAE 5 at low temps (hence the w), and like a SAE 30 at high temps (hence leaving off of the w). > > If you cannot grasp this concept soon, I’m going to start to question your ability to run this forum. This is honestly one of the silliest arguments that I’ve seen in the history of the Internet. Only multigrade come with a W number. Go read the chart above where the cSt for 20W is the same as cSt for 20 at 210. If a fluid flows at X when cold, and another fluid flows at X when warm they are the same X-speed-viscosity. Obviously one fluid will not flow at the same rate at two different temperatures so it gets two ratings. The only reason some bottles only have one number is because they were only tested at 210. --- _[View the full topic](https://forums.speedlife.net/t/oil-how-does-it-work-split/262189)._