I'm still waiting for SM CS to hit the shelves here. Maybe Chevron switched to a Grp3 base oil, like Mobil did?
On another note...I use Havoline when I can't find CS(it can be elusive around here). My Volvo has SM Havoline in it now and it definately feels different than the old SL stuff. Not nessecarily better...just different. I suppose a UOA on the Havoline SM would be in order.
Well, I would just assume that what we are seeing is a change in marketing the "Isosyn" term versus any base oil change.
For GF-4/SM, the majority of 5W-30's will be at minimum Grp II, with Grp II/III blends and all Grp III formulations.
At this stage of the game, a motor oil blended from hydro-cracked basestocks is more the norm & any label trying to promote this, as a competitive advantage, is out-of-date.
