Re: Is it really synthetic just because it says it is??
I used to think about Mobil/Castrol issue just like you. However, as I studied UOAs at BITOG, I learned that syntec had always better wear numbers than mobil1. Why? Ultimatelly, the additive package is more important for wear than the base oil itself. Like you said, the properties of group 3 are almost as good as PAO. Some oil makers take the savings on cheaper base oil and invest them in better additive package. Be a judge yourself.gwoodall said:In 1997 Mobil lost a lawsuit against Castrol. Castrol had reformulated their synthetic line of motor oil, switching from a 'true' 'synthetic' polyalphaolefin (PAO) base stock to a hydroisomerized petroleum base stock commonly called Group 3. Mobil was challenging the labeling Castrol Syntec oil as synthetic.
The fact is that although Group 3 is from petroleum it has little in common when looking at the molecular structure than less refined common motor oils. Its test numbers are close to the performance of PAO based synthetics.
My gripe is it should be cheaper, but it isn't. Castrol Syntec, Valvoline Synthetic and Pennzoil Synthetic are all Group 3, not PAO. I have switched from Castrol Syntec to Mobil 1 simply because for years I thought I was using a motor oil that was not derived from petroleum and feel mislead, although the Syntec is still pretty good stuff.
Mobil 1, Amsoil, and I think Red Line are PAO based.