Oil Spec for the 6.4 Hemi

[RKCRLR]

Late 2025 update. Castrol Edge now carries the MS-12633 and MS-A0921 specs on the label.

Castrol states their Castrol EDGE Euro 0W-40 A3/B4 is:
"Suitable for use in the following specifications: MB 229.3, Chrysler MS-12633 / MS-A0921"

Castrol® EDGE Euro Car formula | Castrol® USA​

Castrol® EDGE® Euro Car is a range of advanced full synthetic motor oils engineered to exceed manufacturer test limits, ensuring the highest level of protection and maximum performance for European cars.
www.castrol.com

And their data sheet states:
"Warranted by Castrol to be completely suitable for use in vehicles where the following specifications apply: MB 229.3,
Chrysler MS-12633 / MS-A0921"
https://msdspds.castrol.com/bpglis/...720D19480258B0E005F7BBB/$File/WEPP-D4TD96.pdf

However that doesn't mean the same thing as stating it is certified to MS-A0921. But it is good enough for me since it also meets API SP.