Originally Posted By: BuickGN
Originally Posted By: tig1
The best oil for the dailey driver is most likely a blend of grp 3-4-5.
Why? What does a grp3 or 4 offer that a grpV doesn't?
As Chevrofreak noted, this is not correct. At the dawn of common automotive use of synthetic oils, a couple mfrs used some primitive diesters that were incompatible with many other oils, and apparently, would actually solidify when mixed with other oils. Now, as many others have suggested, it's getting hard to say that an oil is this group or that, as most of them are balanced mixtures of different group base oils, concocted by the different brewers to achieve the particular goals they are shooting for.