Synthetics are supposed to be far superior in the boundary layer protection area, Ie: upper clyinder walls during high temps and pressure.
I like their natural abilities to stay cleaner much longer, especially short trip driving in the winter.
I'm most comfortable with Mobil 1 and the FL-820s or the Purolator Pl 24651.
Castrol Syntec NO!!!!!! Not a true synthetic anymore (Pao), I've had trouble with the new formula causing severe black desposits coating the valvetrain area.(That's all the farther I opened the engine up.) After many e-mails to Castrol and once they found out my extensive recording keeping proving it was their new Syntec they quit responding?
So I assumed guiltly.
Paul
