Originally Posted by kickstand
I am skeptical of synthetic oil, but even more skeptical of amsoil.
I do believe that a synthetic will allow you to go go longer between changes, but I am not under the impression that synthetic will protect better than a regular oil which is also changed at proper intervals.
I don't believe you see very many oil induced failures of engines that are properly maintained. Which leads me to the conclusion that either oil will sufficiently protect your engine if you maintain it like the manufacturer recommends that you do.
I primarily use old school oil, and have always had good luck in doing so. However, my cars are starting to get newer, and are starting to require it from the manufacturer.
That's pretty much where I'm at. I do run Amsoil, I got a preferred membership for free so cost-wise it was actually a little cheaper than some of the other synthetics (Mobil 1, Royal Purple, etc.). I'm currently on 12k intervals, but around 5-6k I'm going to send in a sample for analysis. I do hate all of the marketing bullshit I get from them for being a preferred member, mainly I hate their stupid monthly magazine. Cost wise I think I'd be about even if I was going with 5k changes on dino oil.