Group III vs. Group IV

Joined
Jun 8, 2006
Messages
46
Location
Ontario
I've been told that Shell Rotella 5W40 Syn is a Group III but Amsoil Series 3000 5W30 diesel is a Group IV. What's the difference?
 

JHZR2

Staff member
Joined
Dec 14, 2002
Messages
46,766
Location
New Jersey
time to search [Smile] rotella is supposedly the best group III basestock out there (Shell XVHI), and Amsoil supposedly buys its base from Mobil, which ensures its quality. The differences really have to do with origin, cost of manufcture, etc. In reality, the longevity of the basestocks in normal service, and their actual performance - for, say OCIs under 10k miles is negligible for the most part, though some opinions may differ. Doa search, youll find a LOT! JMH
 
Top