Down here (Chile) Prius manual has 0-20, 5-30 and 10-30 as the allowed oils. No word about replacing them sooner or later depending on viscosity. In fact, 0-20 isn't sold. Seems Toyota USA has stringent requirements, anyone knows why? Sent ?
Could be We also have other restrictions: only to be serviced at Toyota for valid warranty; a gallon of 5-30 costs about 100 USD. Hope our complains are heard sooner than later. Sent ?
First, you meant 5W30 and not 3W30, second you never told us how you use the car. That has a bearing on the best oil choice.
I was telling him to buy 100% synthetic. I see you found one of the few that has the blend. Sorry for the confusion
First you have to understand these numbers: Viscosity Classifications 10W-40, means that cold start viscosity is 10, but this is measured only at -25° C, for your climate probably totally irrelevant, you could use 0W, 10W or even 20W. But stil this number gives us hope that viscosity at 40° C will be lower if you use 0W instead 20W. The second number is more important it represents viscosity at working temps (100° C) and lower you go better for the fuel economy, but question is if the engine will tolerate it. There probably is also a high limit but 40 probably won't damage your engine. So 5W-30 will have lover viscosity and lover fuel consumption than 0W-40, if you can't find 0W-20 just fill it with 5W-30, if you find ACEA A5/B5 it will have lover viscosity than normal 5W-30 (on the limit) and it can be very close to 0W-20.
