RALPH MAKES SOME GOOD POINTS AND SOME BAD ONES...STRAIGHT SYNTHETIC CAN DAMAGE NEWER ENGINES.. ON A TIGHT ENGINE YOU CAN ADD SYNTHETIC AND THE SYNTHETIC WILL ACTUALLY BOND TO THE CYLINDAR WALL. THIS WILL MAKE FOR A TIGHTER FIT FOR THE PISTON. IF THAT HAPPENS YOU CAN ACTUALLY FREEZE A PISTON.. STRAIGHT SYNTHETIC WILL ALSO LEAK EASIER THAN OTHER OILS. RALPH NEEDS TO MAKE ACCURATE POSTINGS..I AM SURE HIS REBUTTAL WILL BE THAT HE IS ALL KNOWING AND THAT HE IS A PROFESSIONAL MECHANIC OR A DOCTOR OR BUILDS ENGINES ...WHATEVER...I HAVE ACTUALLY SEEN IT HAPPEN...