Just came from my first service(one year/15000km) and noticed that on the bill it says they put 5w30 oil in. I thought that the prius used 0w20 oil. Is this ok? I'm sorry if this has been asked before, but I am writing this from my phone and I can't search properly. (I'm still in the city where the dealer is.) Thanks.
It is supposed to be 0w-20 synthetic oil to get the maximum fuel savings, but the manufacturer does allow the use of 5w30 weight dino oil with one caveat. If 5w30 oil is used, the oil must be changed to 0w20 synthetic oil within 5K miles. Here is a link to Toyota's FAQ about synthetic oil: Toyota Owners - Frequently Asked Questions (FAQ)
Can anyone answer the question of WHY 0-20w oil MUST be used. They state that you can use 5-20w but it MUST be changed after 5,000 miles. It would seem that if the engine used it for those 5,000 miles why is it so necessary to change it back to 0-20w. What harm if any, will come to the engine if one uses 0-30w or 5-20w rather than 0-20w. I haven't been able to get a definitive GOOD answer on this subject.
Toyota got it's fuel economy rating on 0W-20 oil so they have to spec using 0W-20 oil if they want to keep advertising that fuel economy rating.
