Interesting. I run Amzoil 20W-50 and the oil temps will vary (during a run) about 30degrees C. Larry sandiego16V > Castrol Syntech 5W50 all year round, and I drive like > a madman. > As a bonus, the motor oil temp gauge used to go up and > down with mineral oil. Now it is rock steady in the > middle of the range - less friction. > > Cheers. > > Marc