# Oil... how does it work? \[split\]

**URL:** <https://forums.speedlife.net/t/oil-how-does-it-work-split/262189>\
**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:** 181

<div class="post-metadata">

**Author:** ![KillerBlackbird](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/killerblackbird/32/6525_2.png) [@KillerBlackbird](https://forums.speedlife.net/u/KillerBlackbird)\
**Post date:** [January 11, 2012, 4:50pm UTC](https://forums.speedlife.net/t/oil-how-does-it-work-split/262189/181 "2012-01-11T16:50:06Z")

</div>

> [@Justpicked up a new summer beater \*\*CRX inside\*\*](https://forums.speedlife.net/t/justpicked-up-a-new-summer-beater-crx-inside/47826/18):
>
> Thinner than what?
> 
> If oil is made thinner for start up, it means it thickens up later no?
> 
> Or does it get even thinner once started?

Thinner than 90 weight gear oil at 20_F.  
Drain your Subaru and fill it with 80w90, wait until its -20_F and start it.

Engines are built to certain tolerances that require certain weight oils to properly lubricate engine components in tight little spaces. Some Hondas take 0w20, my S2000 requires 10w30. It all depends what the little Japanese engineer decided would work the best.

If your car sits for a day and you start it, the oil has to circulate through the oil pump and reach those areas. If the oil is too thick upon start up then it wont flow properly possibly creating unnecessary wear on those engine components. Thus, you would want a thinner oil when starting to quickly protect those areas and once the engine has reached operating temperature you would want a slightly thicker oil for better protection against heat and I imagine as engine tolerances increase in size.

---

_[View the full topic](https://forums.speedlife.net/t/oil-how-does-it-work-split/262189)._