Mobil 1 is a good example of a high-end Group IV. Group III lubricants are made from reprocessed petroleum products normally left over after making crude oil into gasoline, diesel fuel, heating oil and other products. They're more modestly priced, and have many of the desirable characteristics of the higher-priced spread. In much of the world outside the USA, Group III-based lubricants are not permitted to be marketed as ?synthetic.? Castrol Syntec is a good example of this type.
Gee, the spammer's blog actually provided some information!!! How about that!
Where I get my oil, Mobil 1 and Castrol Syntec are the same price, so I guess I'll try the Mobil 1. I was using Castrol because I have been using Castrol for about 25 years now, and have gotten 4 engines well over
200,000 miles with it...BTW, I didn't realize...at least, the new bottles of Castrol have the BP logo on them...
Also, in the 'beaters' I have been using ...er, Pennzoil? High mileage formula with Slick 50 in it. I'll run it for 3 changes and then use Castrol H-M formula, since it has worked wonders on the Supra!
Since I started using the Pennzoil in the Mazda, that noisy Hydraulic Lash Adjuster (HLA) has been giving me a LOT fewer problems! It hardly taps at all anymore...