Thanks Terry for all the information. I am sort of a Mystik guy but I actually have not used Mystik much up until recently. A long time ago I used to use Pennzoil-Quaker State but after I heard some negative stuff about those oils I started using Castrol and Valvoline. I also have used Mobil 1 and even Amsoil from time to time. The BOBISTHEOILGUY web site is really interesting and I wish I had found it earlier. I try to use the best motor oil, oil filters, etc., at the most reasonable price, that I can find for my car. But how do you determine the best motor oil? Actually the only information I have that Mystik is good is that three professional mechanics have told me that they like (or liked) Mystik oil. One was my father (who is deceased), and the other two are still alive. One raced cars (and used Mystik) as well as being a mechanic. I wish somebody would do a study of Mystik. I am really impressed with Auto-RX which I first discovered after finding this site. Auto-RX really works-I know. I am thinking about using Shaeffer's Oil at least in the wintertime and also Shaeffer's #132. It is obvious that many people who visit this web site really know a lot about motor oils. Every product that has been praised at this web site has worked for me. It is great finding stuff that really works. Right now I am using Mystik but I am tempted to use Castrol or Chevron because of what has been said by people at this web site.