0w-20 or 0w-16 oil? manual conflicts

I too found the same "misprint" in the Warranty & Maintenance Guide. Thanks for getting the answer from Toyota. Once Toyota's extended care is over, I plan on doing the maintenance myself, as I have done on all of my cars. I was concerned because 0w16 appears to be only available from Toyota and a few other random brands. 0w20 is much more widely available and less expensive.

Researching the question of low viscosity leads me to believe it greatly decreases friction at startup, especially when the oil is cold. I am concerned that long term engine health will be impacted, especially wear on the rings leading to greater oil consumption and other problems. I will re-assess the viscosity requirements of the car after 75K miles. I would think that bumping up to a higher viscosity would be better.

I put a lot of miles on my previous Prii that I've owned and worn rings was a big problem on the last one I just retired. Once the rings began wearing out, I saw all kinds of problems...beyond the additional oil. Catalytic converter throwing codes, O2 sensor plugging etc. Maybe 0w20 will burn cleaner through the worn rings if it leads to that...

Looking at the EPA ratings on the window sticker compared to past years, there was only a modest improvement in mileage with the decrease in viscosity. All well and good, but when 0W20 first came out, the expense was twice what it is now. At today's 0w20 prices, is the added cost of the oil worth the couple extra MPG?

 

I think 0W16 is the “up and coming” thin oil to improve mpg. Is is really 0W15 but labeled as 0W16 so it would not be confused with 15W oil

 

This is all due to CAFE standards. Follow the Europe and Australia manuals without the CAFE restrictions of using OW-20 oil. Your engine will thank you. Currently using 0W-40 with no issues.

 

I once watched my oil pressure go down due to sitting in NYC traffic. I spun a bearing because of it.

I use 5-40 in my race bike. Ran it at redline it's whole life and it has 30k miles. I use 15-50 in the Prius in summer in florida. flor cant imagine using 20wt anywhere but the North Pole in january.

 

I don't think that "sitting in NYC traffic" was the CAUSE of anything.
Sounds like the oil FLOW failed......due to a failed pump or plugged inlet or a hole allowing all of the flow to go somewhere else.

 

I want to make my Prius last longer. What's viscosity oil is best for 300K+ life even if it's at the expense of some fuel economy? My 2009 engine is still going strong at 314K miles. I want my 2019 to last as long.

 

So the 2019 oil cap says 0w-16. The manual says 0w-16 everywhere except for the part where it says if you used 0w-20 instead of 0w-16, then change the oil at the 5000 mile interval where you'd normally skip the change (due to 10K oil change intervals).

Is there any difference in the engine between 2018 and 2019 or is this strictly about EPA fuel economy? If so, then there's zero chance I'll ever dump something as thin as 0w-16 into my engine. Will I void my warranty if my engine fails when I used 0w-20 assuming that the thicker oil wasn't really the cause especially given that the 2016-2018 already requires 0w-20.

Did the retroactively change the 2016 requirement to allow 0w-16?

If the Australian manual allows 10w-30 (I'm never in freezing areas), then I think I'll use that. I'm almost thinking I'm going to forego the free 25K service unless I can convince them to use thicker oil.

I need the engine in this Prius to last 300K+ miles like my last Prius.

 

Interesting. How much did you get that Mobil 1 expended for?

 

The thing to consider is warranty. I wouldn't risk getting to almost 7 yrs when the warranty on the engine runs out and have a problem - and they then point to an oil different from what YOUR Service Manual specifies. They are fully entitled to point to the oil (they can analyse it) and say - sorry, no go.

 

I suppose if you change it every 5K miles with 0w-20, you're still abiding by the guidelines.

 

What country are you in - your profile is blank. If you're in a country which specifies 0w-20 you're fine, but not if you use what they don't specify. TOYOTA Australia and TOYOTA USA seem to have different criteria. Second guessing what they'll say in 6½ yrs if you've got a warranty claim - I wouldn't be doing it - they can easily wipe their hands of it. All they have to do is get the oil analysed and they've saved a $5000 rebuild.

Just put the right oil in.

 

More like a year since I drive 50K miles / year and the power train warranty expires at 60K. Not sure where 7 years is coming from since it's 5 years or 60K miles in my warranty booklet.

 

Ahhh - you've now inserted a country. Here in Australia, the drivetrain has 7 yrs/unlimited kilometres warranty.

[ Toyota Introduces Toyota Warranty Advantage | Latest News ]

 

Amazing. I'm moving down there!!

 

I wouldn't put too much stock in Toyota's ability to pick the optimum engine oil weight, for engine longevity. And I doubt anything changed in the engine, between 2016 and 2019. Optimum oil for engine longevity, who knows: 5W20, 5W30?

I get bulk Toyota 0W20 cheap, no problems so far. And no drop in oil level from one oil change to the next. Which is a first for me, compared to our past Hondas. Arguably, I don't go very far between oil changes...

 

Why would they? The goal of thinner oil is to increase their marketing efficiency numbers. If the engine lasts longer Toyota loses money from potential service and sales.

 

I have paid for access to toyota-tech and browse technical documentation for Prius 4gen. They are two sections for Prius 2015 and for 2019.

Prius 2015


Prius 2019

 

I will bet if you look up my 217 which is the same as the 2019 it will say 0W20

 

This was a document for Prius 4gen, all years. 0W16 was introduced for Prius 2019 (manufactured 2018/11+).

 

Your 2017, presumably built for sale in the U.S., isn’t covered at all by the RM32xxE series Repair Manual on toyota-tech.eu, from which @ruphert kindly shared the extracts in post #57.

The RM3200U Repair Manual for your car, available by subscription to techinfo.toyota.com, is internally inconsistent. Under General: Specifications: 2ZR-FXE Lubrication: Service Data, both the 2016–2018 MY and 2019–2020 MY versions of the topic specify ILSAC GF-5 multigrade engine oil, SAE 0W-20 viscosity, for USA models. Under Engine/Hybrid System: 2ZR-FXE (Lubrication): Oil and Oil Filter: Replacement, however, the 2016–2018 MY version specifies 0W-20, and the 2019–2020 MY version specifies 0W-16, for USA models. The specifications for Mexico are as listed in post #57 under “except Europe and Korea.”