Has a majority opinion been reached regarding synthetic vs. "traditional" oil?

So is it ok to use 0W20 in a Gen2? The Toyota spec as of 2007 was to use 5W30, but 0W20 really only became available with Gen3 in 2010. Is the Gen3 design changed to allow 0W20? Or is it required to meet mileage claims? Will 0W20 provide better mileage on a Gen2?

 

OP, check out the used oil analysis posts in the Bob Is The Oil Guy (BITOG) site HERE . It will give you much to think about. Take your time. Don't hurry. Much will be new to you and you won't understand, but you will also learn much.

Our 2009 hatchback requires 5k mile intervals with 5w-30. I use 0w-30 M1 and stick to 5k mile intervals. I could easily use conventional and not sweat it, but I use 0w-30. I use the same in the 1999 F250 Super Duty V10 and the 1998 Z28 Camaro. It makes buying oil easy to use the same for all.

For the 2012 C, I use 0w-20 M1 at 5k mile intervals. I don't care about what many would perceive as a waste of money or oil. My oil, my money, my world view. It's easy to keep track of the changes at 5k mile intervals across the fleet, and I do the work myself and don't mind at all. I enjoy changing oil and working with my tools on my vehicles.

Amsoil is a special animal. They don't abide by many of the standard protocols. It's expensive to do the testing and they explain it away in their literature. Most of their oils are good to very good. Some are great. Some are run of the mill. The aura is what they are all about. Super-filtering does many things good, and that is also what they sell. They provide long-life filters to go with their long-life oil. Not all filters are fit for 10k+ miles and more than a year's service.

My C, on average, is about 25% electric useage. For a 10k mile interval that's 7,500 miles, and at that usage I could easily go with a conventional oil and everything would be hunky-dory. But I don't as a personal choice.

In a 0w-20 most every oil would be synthetic by nature even if it didn't say it on the bottle. It would be good for 10k miles.

Used oil analysis (UOA) are good to do. They give you an idea of what your oil is doing and how your engine is faring. You don't need to do them ever oil change if money is tight. I do them for the first two or three and then when I feel like I want to know. $25-30. Many use Blackstone Labs. I do. You can buy pre-paid kits or buy kits and them pay them as you use them. You can see how your engine wears and how your oil is taking care of business. The most common way to watch when it's time to change oil is the TBN number. When it gets low your oil's ability to absorb acids is diminished and it's time to change. After that would be the viscosity - is it still in range. Fuel dilution. Water. Antifreeze. Silicon (which initially can come from sealers/sealants, but after they subside it would be from air filters not filtering out dust.) Then there's the wear numbers of the various metals in the engine. There's a page on the Blacstone site that explains what all the numbers mean.

There is NO concensus about synthetic vs. conventional, how far to go on them, or what you should do in any particular circumstance (other than they flow better at cold temps and what that would mean to the individual vehicle, individual location of the user, and the proclivity of the individual user to start and continue fights about conventional vs. synthetic.) For my money, and I have money for now, I go with overkill.

YMMV.

There is much to learn. Don't be shy. And BITOG is your friend.

 

Toyota has not changed the spec for G2 Prius to OW-20, it remains 5W-30.

That said, I have read more than one well informed person who will use 0W-20 in the G2 Prius in the frozen cold of winter, and 5W-30 the rest of the year.

 

In a post last year, a member of PriusChat got a letter from Toyota USA saying 5w-20 was OK in Gen2 as long as you kept to the 5000-mile drain interval for Gen2's. There are also some Toyota charts posted that show fairly wide selection of oil grades applicable to Gen2 - which was always confusing that it conflicted with the USA owners manual 5W-30.

Conceivably 20-weight gets better MPG especially in winter, but we're talking at most 1% I think. I have personally stuck with the 5w- and 0W-30 (winter) in my Gen2. As alluded by Sage, the Toyota synthetic seems to get high marks for being lowest viscosity, not sure if Toyota has a 0W-30 synthetic but if so that could be lower viscosity option or also Mobil-1 0W-30 is a low viscosity version. Sage plans to use Toyota in winter where lowest visc helps most. In summer heat the oils are all quite thin. My personal philosophy is that Gen2's possibly get more fuel/gaso dissolved in the oil, so I like to stick with 30-weight oil on the idea that viscosity gets lower with use.

 

It's Amsoil "Signature 0W-20" gallon bottles I have. The A5/B5 is most definitely labeled on them. Went to the garage and triple checked before posting that. Remember, there was a period when the older Amsoil 0W-20 did not have a A5/B5 on any version.

 

Correct,

As long as those well informed persons stick to the above with careful observation to the change of the seasons, that is fine.

On the other hand 5w-30 in arctic cold weather can be helped with a plug in sump heater for a couple of hours before starting the engine.

My G2, using 5w-30 has no problems starting at -20 to -25F. I make sure my battery is in top shape. I have not, to date, installed a sump heater on my G2. My diesel truck, on the other hand, uses a sump heater for startup. Its' oil is:15W-40.

DBCassidy

 

I probably should have clarified. I was not thinking of the Prius living in the Artic tundra -- just the snow belt of Europe or the US.

The change to Ow-20 in the winter is for better fuel economy while the car is warming up, not because of any start-up issues with 5w-30.