I figure that the engineers who designed/developed the engine got some pretty big bucks to say that we should use 5w30, compared to the opinion of a mechanic whose training probably doesn't hold a candle next to the engineer's. I'll use 5w30.

 

Try Marvel Mystery Oil. It's a good cutting oil and will help things "wear" in evenly. It'll also do wonders for your seals and gaskets. LOL!!

 

I would run mix MMO/ the oil in my Limited Modified 4 cycle racing kart motor....man would you eyes burn.

I accidently put 10/30 in our '06 2.4 and I honestly could tell immediately the difference in performance, the engine felt booged down.