Best engine oil for car - Toyota genuine? Honda genuine? 0w-20 5w-30?

Our climate is pretty much that of Vancouver I think. Yet I was flabbergasted to see my Toyota dealer threw in 10W40. When I went to them to complain (year later) they claimed it was the official recommended thickness according to the importer for the gen2. But they also said it had since been changed to 5W30...

0W20 is hard to find and indeed >10€ per liter. Even 5W30 is hard to find under 7€/liter even in bulk (5liter cans). 10W40 is cheaper than milk... (exaggerating a little, but 10€ for 5liters is very common, so Toyota saved 20 to 40€ by using 10W40 instead of 0W20 or 5W30 )

 

Yes, in the UK that is the case.

 

All the more weird that a few miles away, across the pond in pretty much the exact same climate, they adviced 10W40 until a year ago (and now 5W30).
BTW, 'my' Toyotadealer is part of the importer since a year or two (so no longer an independant franchise but really directly linked to the importer who has a dozen or so Toyota dealerships).

 

I misused the term "pond" and threw you off. I'm in Holland So quite literally a few (dozen) miles away.

 

An oil zealot I am not, but if 30 PSI with 10W-30 oil is good enough for a diesel making 1700 Tq and 475 HP, 0W-20 isn't going to HURT and damned thing in a low power / low tq application like a Prius.

One thing most people do not realize is that oil FLOW is FAR more important than oil pressure.

BTW, similar "it's too thin" arguments were levied against Ford when they announced 5W-20 in their 500HP/500Tq 5.4L Supercharged monster - Ford GT. For a major manufacturer to WARRANT an engine with those specs for 3/36 is impressive and speaks volumes more than all the internet trolls in the world could.

 

QUICK oil flow is far more important than high oil pressure and just as you wrote it helps the engine! It's been L O N G understood that the most wear occurs at start-up, not due to lack of oil pressure, but due to low oil flow. This is especially true at temperatures below about 20*F.

 

Just did change four on my 2016. At this rate I will be at 100,000 miles in about three years.

 

For 10 years the Toyota UK dealer in Hampshire (the next door county to Berkshire) used bulk 5W-30 semi-synthetic for my regular 10k oil changes. The brand varied from Castrol Magnetex GTX to Shell Helix HX7-AF, which imagine was a cost based choice (meeting Toyota spec.). I have recently switched to servicing myself and I am using the Comma recommended alternative semi-synthetic oil, Comma XTC5L (XTech).

 

So the consensus is people are skipping 5w-30 for 0w-20 as far as motor oil in prius ii? That would be great because that oil weight is the same for our '14 Sienna.

 

Typically, automotive engineering relies on evidence-based results for design, not consensus (which is, by the way, the weakest form of agreement except agreement born of fraud and lies). What evidence is there that switching to this weight of oil is advantageous? I will stick with the manufacturers recommended weight, and maintain the same brand over the life of the car.

 

It seems to me that the low voltage electrics/electronics (including wiring) are likely to be the main (mode) life-limiting features of a Prius 2, given that traction batteries can be replaced at a cost. Regular oil changes of 5W-30 (in spec), or perhaps any other oil, will keep the engine running for many 100k miles... unless there is a huge number of miles were traveled really early in life (which largely seem irrelevant to most on the road Prius 2 given their age, even the newer ones at 9+ years).

 

I don't think there's consensus. I'd think stick with 5W30 for the second gen Prius. I'm almost tempted to go to 5W30 for my 3rd gen, but I never go there. Guess I'll just stick with the Owner's Manual recommendation. Even that varies though, 'round the world.

 

Got it, I will stick with 5W30 for my Prius ii

 

Agreed.

Dorihachigo, Toyota doesn't reveal exactly what tests it performs, but you can be sure Toyota has done thousands of hours of testing using the factory recommended oil. When you introduce different oil, you may introduce a variable into your engine that hasn't been accounted for by the manufacturer.

That being said, an once of common sense is applicable here. If you're going to tow with the car, take it to the race track, or live in a very warm climate (Phoenix, etc.), it makes sense to go up in viscosity a grade, as the hotter engine temps will thin out the oil.

Likewise, if you live in a cold climate and will only be running your oil over the winter, going down a grade can give you a bit better fuel economy.

Therefore for the majority of us:

2nd gen Prius (05-09): 5W-30 or 0W-30
3rd and 4th gen Prius (10+): 0W-20

 

Do it.

When’s the last time your Prius has truly seen cold weather (even though north of the 49th parallel is known for being tundra-esque)?

Vancouver Area was beautiful when we were there in 2010 for the olympics.