What kind of oil for your Previa?

"As for the oil.. yes, although it recommends 10W30, it also recommends API type SF or something ridiculously outdated like that... as the engine wear, oil consumption increases, so it maybe necessary to use thicker oil... I now use 0W40 to keep wear and oil consumption under control.... if you prefer to stick to 30 weight, then I recommend 0W30 or 5W30 instead to reduce cold start wear... no, it's not going to cause any problems" - TheMAN
http://www.toyotavantech.com/forum/showthread.php?2923-Beater-Previa-But-I-Like-It-Anyway