Castrol imports a full synthetic from Germany for its Syntec line. It is available at Autozone in a 0W-30 weight. Look for Imported From Germany on the back label of the bottle. It performs very well in used oil analysis. http://www.bobistheoilguy.com is a great site for great information about oil.

Be wary of the Amsoil 25k/35k claim. They are always followed by "or one year". You also need to change your filter at six months and add a replacement quart or so. Plus, you can only get that mileage under great conditions. If you have a lot of shirt trips, the that claim doesn't apply. Mobil 1, Amsoil, German Castrol and Royal Purple are alll excellent oils. I bought a bunch of the Pep Boys calendars for Buy 3, get 3 Free Mobil 1, so that will be stocking my shelves for a while.

And how come it is so damn hard for people to spell "Mobil" correctly? Why do so many people feel the need to add an"e" to the end?

 

Red Line synthetic works well, too.......

 

I am also an Amsoil fan but I also change it at the recommended intervals. The overall cost /year is not significant for me since I am retired and don't drive to work every day. I will probably end up changing the oil in the RT two or three times a year.
By the way, the Mobil 1 site says their 0-20 oil is good whenever 5-20 or 0-20 oil is recommended by the manufacturer,
Howard

 

5W-20 Mobil 1 will be available in the spring.

 

I am curious why they are releasing a 5W-20, when they say 0W-20 works in
engines that require 5W-20. Makes me question is the 0W-20 is not a good
choice for the 5.7L

Rex