Amsoil says once you put their oil in you can not change back to standard oil. Is that true or just a scheme?

No :rolleyes: they don't want you mixing oils if you run it, shortens oil life and reduces performance benifits. Sounds like Bull Sheet to me and for $10.00 a Qt. is it really worth it ??? I'll stick with the Pennz Platinum Syn. :D
http://www.amsoil.com/storefront/sso.aspx

scheme to me, though i would pick an oil that you prefer, i prefer the mobile 1 full synthetic OW-30, and stick to it. Almost 100% postive it wont hurt anything they just want you to keep buying their product. I usally mix 1 qt of Lusas Oil in my vechicles, 4 wheelers ect.

I've been using Amsoil exclusively for about six years. I use their 100% synthetic rated for 25,000 miles. I change filters at 5,000 mile intervals and top off each time. The top access filter replacement on the 2.4L should make changes even easier.

I use Mobil One, but at work the boss decided to use Amsoil in a GMC gas, dump truck and now that it burns a quart a week I wanted to order regular oil and use that .. Amsoil told him he could not change back. Sounds like BS to me but I want to be sure before I go back to regular oil. BTW the truck has over 100K miles.

i would put in mobile one full synthic. with a qt of lucas

You can convert your car to and from synthetic all day long, as long as you drain the system completely each time, and change out filters.