Daniel, Maybe that is why Chevrolet recommends a PG oil change every 12,000 miles for normal service and MORE OFTEN for severe service for all Corvairs, 1960 -67. Regards, Bob Helt. In a message dated 8/5/2012 5:34:48 P.M. US Mountain Standard Time, dmonasterio at hotmail.com writes: in my area.BTW, my PG oil (on a GB) usually goes up to 240ºF