What is the best engine oil for a 2005.UK Prius in 2024.with 140,000 miles on it. Most of the oil finders now recommend ACEA C3 oil which is also API SN so exceeds the specs in the manual. However, slightly cheaper is ACEA A5 also SN. Would this be better fuel economy but less engine protection. These are 5w30 oils. There's also 0w20 but one Im looking at although it is SN it's ACEA is C5. Does the ACEA rating matter or is the API rating all that matters.
Your ratings today are generally better than what the car called for as in looking at the year model we're discussing so to me really what's the point any of those oils would be just wonderful and fine and I'll take that to the next level I change mine in 10,000 mile intervals which many people don't appreciate My cars are going into the four and 500,000 mi range I appreciate that without having to do my oil changes every three to five thousand miles everything comes out looking good and goes in looking new so seems the point is moot in 50 years of driving I've never had an oil related failure and I could tell you some horror stories early on of not changing oil but we don't need to go into all that
I just say the oil you pour in the one NZ is a very wide range engine It's not going to get too pissy about engine oil unless you make it too heavy.
