Engine Oil Mythology

While i agree with the reading I believe there is a difference in oil for older engines. Optimally you want a oil with high zinc and phosphorus ppm. You can take a look at mobile ones site. There is noticeably more zinc and phosphorus in their 15w50 than in their 5w20. Most of the lighter weight oils are lower on the content because newer engines dont need as much as older engines and the emission issue plays a role as well