Question on head gasket and oil additive

[Myron Piatek]

Originally Posted by big blue galaxie

The motor oil is now named Amsoil Signature Series 0W30. The also have a 0W20.

Those are not the same oils. The Dominator Series is new as of last year and are fortiufied more for the racing environment. The Signature Series 0W-30 may have gotten reformulated a year or two ago. I'm only speculating, but it may have to do with newer model emission regulations and compatibility, similar to a new diesel formulation for 2007 & newer diesel trucks. I believe the zinc content has something to do with it. The race oils, older diesel, including the HDD 5w-30, and some of the others, still have a large amount of zinc and similar additives. It's all good stuff nonetheless.