Roadie, you replied to a 13 year old post.

*SOME* Amsoil is still a true synthetic, specifically the Signature. They have several different oils. I believe that Mobil 1 is a Group 3 but Mobil 1 EP is a group 4.

To Patrick, who brought up this old dead thread, I'd recommend you use 5W20 Motorcraft synthetic blend and a Motorcraft filter, both available at Walmart.

 

Can you point me to the documentation that says any of the Amsoil or Mobil oil is Group IV? They used to say it was PAO, but not any more.

I can't find any. They claim it is "synthetic" and Group III is called synthetic too. ???

 

This is the best I can find, it doesn't address specific formulation.

http://www.amsoil.com/lit/databulletins/g2880.pdf

Various other sites do say that the Signature series is still a Group IV synthetic, their lesser oils are Group III. For the price of Signature, I'd expect it to be better than Group III. Oil companies are very secretive about what they use for base stock, but it's generally speculated that Mobil 1 EP is Group IV, at least mostly if not all.

Time for Labnerd to chime in with the latest info that he has.

 

About a year ago, I stated on the forum that Amsoil was one of the few left that was still Group IV and Labnerd chimed in and said it wasn't. He said it had some really expensive stuff blended in but it was mostly Group III. I don't know. I can't find any information that states what group any oil is. The term "synthetic" that everybody uses now is used for Group III, IV, and V.

 

In reality - it's not the group that matters, it's how it's done. There are Group III oils out there that are better than some Group IV oils - the Pennzoil Platinum that Labnerd claims is one of the best out there is Group III.

 

I agree. In fact Labnerd keeps recommending Group II oil (Pennzoil and Havoline) and motorcraft blend for us to use and keeps telling us we are wasting our money on "synthetic".

 

The only reasons to use synthetic in my opinion are to allow extended drain intervals, better flow at low temperatures, and better resistance to high temperatures.