I have a 05 Prius with around 190K miles. Question one I have never personally changed the transaxle fluid and don't know if it has ever been changed, should I change it? I have learned over the years that sometimes its better to leave things alone. Question two I run 5w30 Mobile 1 full synthetic oil. It's becoming winter time and getting in to the high 40s right now. Last year it snowed I live in upper SC. With my mileage what do y'all think about running 0w30? And just wondering how about running 0w30 year around. Thanks for any info
Should definitely be changed, just make sure to remove the fill plug first. There are detailed directions around here somewhere. Can't comment on the oil selection.
A 0W-30 will give you marginally better fuel economy while the oil is warming up and is also good for summer use. As long as you are using a decent synthetic oil, there is no reason to not use a 0W instead of a 5W oil.
That's generally true on a conventional automatic trans, where the change process can stir things up, especially if a machine is used to flush it out. But on yours you should change it. Please consider sending off a sample for analysis and posting the results here. I run 0W20 year round.
R&G Laboratories, Inc or PdMA Corporation - Oil Analysis - Excellence in Lubricant Analysis Ask for regular analysis plus viscosity index. Mention Bob Wilson to get special rate.