Originally Posted by EvilTwin
Switching to full synthetic isnt a problem at all, it wont affect the warranty. The only thing about it is pick one or the other. If you go to synthetic you cant go back. Also, you should probably switch gradually. Next change, use blend and then after that use the full synth.
It doesn't hurt a thing to switch from regular to synthetic. Mixing is actually a very bad thing, ask any good mechanic!