The problem is not your oil but the filter. Replace the filter every time you change your oil with a K&N oil filter! I use Moble 1 5w-20 and a K&N oil filter, it was the most used setup back when the GA16DE powered B14 where being moded all the time.! Been running this for a while with no dry start ups and no oil leaks (replaced the front main before using such a light oil!).