2010 Prius - oil change - synthetic or semi-synthetic

5k mile oil changes is a must if you want to drive it for a very long time. I have also dumped 0W20 for 0W40 weight oil. Much better protection and no loss of MPG.

 

The temperatures are lower in a Prius engine until the EGR is blocked. When EGR is plugged the combustion temperatures increase approximately 400* C (720* F). That's when I believe the mayhem starts.

Also the Prius switches from Atkinson to Otto cycle using VVT when under load.

Pixel XL ?

 

Wow. Interesting. Glad I'm using 91 gas! (Maximum octane available generally around CA).

 

You guys may be completely right for all I know, but i feel Toyota has been chasing fuel economy with high-ish compression and low-tension control rings since the early 90's when these ring coking issues first surfaced with Corolla engines. It seems like a recipe for hot blow-by (high cylinder temps) to me and a volatile oil bakes onto the rings and plugs the return holes. This is the point of no return aside from tear down. Despite the higher expansion ratio the Prius engines still play the high compression, low-tension control ring game and thus my theory. Also, gen 2 suffers from the same control ring coking without external EGR and zero head gasket issues aside from the occasional character running out of coolant...

 

Well that's just flat out wrong. VVT can only turn the intake camshaft relative to the crankshaft, it can't change the actual profile of the cam lobes (unlike Honda's VTEC, for example). The camshaft can only be advanced so far until the intake valves start opening during the exhaust stroke, so while it can get "less Atkinson" to a degree, it never gets anywhere near full Otto operation.

See the cam timing diagrams about halfway down the page here for more info. "Range 3" is where maximum advance occurs and you'll notice that it does this to get "internal EGR" by intentionally blowing some of the exhaust out the intake valve to get sucked back into the cylinder on the following intake stroke.

 

I'd also cast my vote in favour of synthetic over the blend. As another Canadian owner the service interval on gen III was 6 months or 8000km's, and since they are quoting a longer interval for you, it makes me more convinced that the better oil is the way to go.

 

Interesting. My opinion was based on a Toyota press release since I couldn't find VVT data. But real-world data always trumps press releases, thanks.

 

Ah yes, never trust the marketing department It's hard to believe they can say "the Prius engine can maximize fuel efficiency while still producing maximum power" when the Prius ICE output is clearly only about 75% of a Corolla's output using the same basic engine design, to say nothing of the version Lotus is using with a supercharger added.

That said, I do remember the effective compression ration being about 8:1 so that part of the press release appears to be correct.

 

Our 06 civic hybrid had dual cam lobes: low-lift were used most all the time, but in more challenging conditions, say accelerating up an on-ramp, hydraulic shifted over to the high lift lobes. You could feel it kick in.

 

Oh yes! VTEC Powered!

 

I was looking at the Mobil 1 Extended Performance oil filter box (20k mi rated) and noticed 99%+ filtration rate for particles >30 microns. I was searching on Fram's website and saw their Ultra filter rated for 20k miles, with 99%+ filtration rate for particles >20 microns. I may switch to the Fram 20k mi filter...

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