I suppose I didn't word my question very well. I absolutely plan on using synthetic oil, the question is when to start using it in a brand new engine. I've heard that synthetic lubricates so well, that the engine parts will not have proper friction to break in properly if synthetic is used too soon. I've used synthetic in my wifes Honda...now over 115,000 miles, and it runs like new. I started using it at 10,000 miles, which was 4 oil changes later in the Honda (I change oil OFTEN). Should I wait till 10,000mi to switch to synthetic in the Rav? Thanks for the previous responses.