Originally Posted by Shamrock

You guys are speaking way above my head. Why do some people chose Mobil 1 0w40 for their Z's? What is the difference between Mobil 1 0w40 vs Mobil 1 5w30? Only the cold start issue or does the 0w40 have no esters in it while the 5w30 does. If the 5w30 has to esters quiet the valve train than it should be used, no? Unless there is a big advantage to the 0w40. No one has addressed this yet. you guys are just arguing. Is it all about the esters?