Dear Frank,
Could you please advise if these oils are suiable for Auto/RX?
http://www.valvoline.com.au/enginearmour/ in 15W40
http://www.castrolmagnatec.com.au/range/ in 10W40
http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9005417&contentId=7065814 in GTX 20W50
http://www.valvoline.com.au/files/productpdfs/8.pdf in XLD Classic 20W50