Hi, Newbie here first post. Please excuse any lapses in protocol. When I bought my 2011 RAV4 the sales manager mistakenly told me the V6 came with synthetic, it doesn't. The oil filler cap is labeled 5W-30. Identical(?) Toyota engines of the same displacement in other models use synthetic. What can be the difference? After 1K or so I switched to Toyota synthetic, and now at 26,000 km I use 0W-20. Any comments or information? Thanks.