This my fourth post on this board, its very informative. I have looked through the UOA posts, but I need a little help. What do u guys and gals think of Havoline 5W 30w oil? Its for a 12 valve V6 02 Taurus. It has 19000 miles. I have been using this oil for the last 3 changes. Also have I voided my warranty for not using 5W 20W ? I live in S. Fla its very hot here.