Why no 10w30

[JohnnyJohnson]

Originally Posted By: ChrisD46
M1 10W30 is a great oil !! ... I run it in the summer (heck could run it all year long) - great NOACK spec for GDI and interestingly enough on the thinner side for a 30W (versus M1 5W30 - go figure ?)


I've run M1 10w-30 not only because its great oil. It was great oil on sale with a rebate. It was my summer oil last summer.

 

[john_pifer]

Originally Posted By: 1JZ_E46
Originally Posted By: Yah-Tah-Hey
What's wrong with just using 0W-30?


All things held equal, a 0W-30 will be less shear-stable, provide less film-thickness, and have a higher NOACK. This is because it is comprised of a lighter base-oil (for cold performance) with more VII (to get it to a 30-weight at 100C). However, there are still some fantastic 0W-30s. Castrol's is one of them (in my opinion). Rather than use a lighter base oil + lots of VII, it uses a decent amount of PAO (which has superior cold-performance for a given viscosity). As a result, it has shown to be very shear stable with a low NOACK (in the 8s).


Is that the case for modern, off-the-shelf Castrol 0W-30?

 

[JLTD]

Originally Posted By: Camprunner
Why don't car manufacturers recommend 10w30 today especially with all the turbo models sold now I would think it would hold up better under hard use?


Because (current company excepted, for the most part) people are stupid, uninformed and unable or unwilling to make a correct decision.

Oh, and CAFE.