Oil Change

On my wife's 2018, We were told by the dealer under Toyota care its the mileage or the 6 months which ever comes first. So it doesn't really matter if she doesn't wanna "scratch the mileage". Its you snooze or you lose on the warranty privilege.
.......... Now this will be a good dilemma. Is oil gonna break down or spoil... or whatever you call it if it only has few miles but its been in your engine for years...?

 

They're just quoting what's in the Toyota publication, not special knowledge.

 

Nope.
Some higher tech PHEV's track EV vs Gas miles and allow engine oil changes up to 2yrs.

 

The 4th gen Prius and the Prius Prime have the same oil change interval, 10,000 miles. My long term average for EV driving ratio is 87%. It makes no sense to change the oil as often as in a standard Prius, when my engine is running so much less.

The 1 year limit is a separate discussion. To me nothing bad magically happens to synthetic oil after 1 year. Just like 3000 mile oil changes have become obsolete with better oil technology, annual oil changes don't seem necessary either.

Taken to the extreme, there are some kinds of oil (Amsoil) that claim they are good for 25,000 miles. Since only 13% of my miles are with the engine on, I could theoretically change the oil every 192,000 miles.

 

Sounds good. Besides thermal breakdown, what about moisture air leads to oil degradation oxidation. Oil thickening, sludge and smudge deposit formation and corrosive wear... blah blah...
Jeopardy clock is ticking...

 

What is:
An engine breaths in and out like a cave. So if enough humid air comes in and leaves drier during Baro changes, you might have a very small quantity of water in the crankcase area, after a year (?). How much of that amount was in the oil and how much was hanging out in the upper reaches of the crankcase?
Would that very small amount effect the oil quality, just sitting there until next start up,

Bonus answer:
Anytime your stinky gasser starts its engine, try to get that engine fully warmed up to evaporate moisture in the oil and crankcase.

Did I win???!!!

 

"What is Purging" if that's what you mean. That's a good answer.
It should be right in your case.
Talk about not doing it, Last time I change the oil in my 65 Austin was almost 3 years go. I probably drove it less than 500 miles since and I start it up every 2 weeks. But I wont say its right.
I'm probably gonna switch to a different oil soon.

 

Just changed oil at 40,000 miles. 4800 miles and 3 months. 65% EV.

Oil was dark black. Cost $27 bucks with Moibil 1 Synthetic and TOYOTA Filter,

Cheap insurance on a $30000 car. Meijers has it for $22.99 for 5 quarts.

Short answer: 1 year or 10000 miles. I do 5000 mile oil changes regardless since that is only 3 months of driving for me.

 

I was talking about an ICE that is unused for long periods of time. Sorry, I left out that important part.

Some PHEV's never fire up the ICE, except for the timed 'fuel and engine maintenance' needs,
if their daily driving never uses up the EV portion of the battery pack. +50 miles with some!

That's where the 2yr oil change intervals come from. A few short engine run cycles and the rest of the time the engine crankcase just 'breathes'.

Other PHEV's routinely rely on the engine for added power and cabin heat. Those can be short run cycles, I'm afraid, and the oil may never get up to temp to evaporate moisture in the oil.

That's where the 10k mile oil change interval comes from, regardless of engine run times and duty cycles.
It's an easy CYA for the manufacturer.

 

Good for you and your 65% EV.
Your engine run cycles must be hard duty on the oil, up thare in the Great White North.
I'm sure in the summer you can stretch that way out.

And good for using the color test!
Wipe the dip stick on a white paper towel. Nasty? Change it.
The easy oil analysis!
Of course you can check this scientifically with a $15-20 oil analysis test kit once in a while.

 

Michigan this time of year maybe 16 miles on ev. Charge at work also so two warm ups a day on the ICE. Snow tires are Blizzak WS80's so they make the ICE work harder. Plus need heat since the car fogs up. Summer oil changes at 5000 miles with the oil still dark gold colored.

Oil is cheap if you shop around. Cars are expensive.

Love my Prius Prime but will go electric next. No ICE maintenance. Although it only takes me 25 minutes to change the messy oil.

 

At the risk of having others repeat themselves, I'd like a little clarification. Seems like 1 year or 10k miles is a best suggestion, leaving out most variables; wouldn't that seem correct?

However, if one could suggest something more accurate, my eyes are open:
I'm near 35k miles, so Toyotacare was finished nearly 10k miles ago. Of those 35k miles, I've filled up 15 times (in my 2 years of ownership), which I calculate approx. 7500 miles. That puts me at darn near 20% ICE. When should I get a change, if not what I reiterated above? What if my last 10k driving was ALL electric (and no defrosting, etc) using Toyota's last free service?

Sillier question: what if I put in conventional? I know, not as good as synthetic or full but is it actually harmful?
2018 Prius Prime Premium.

 

1. There is no color test for oil. Heck, you can buy Purple or Red oil - and those are expensive/boutique ones!
2. Once your warranty is up, you may extend oil changes as you like or not.

My 2016 VW goes 10k on 0w40 synthetic oil. It has a turbo and is direct injection. Hard(er) on oil. I'm actually going over 1 year on the oil b/c of my wife's Prime and COVID limiting the mileage on my VW. I'm not worried at all. I'd go up to 18-24 months without worry. We don't do short trips, unless in the Prime, so our use is easy on the oil.
Once the Prime's free changes are up, I'll probably stick with 10k mile changes, regardless of how much ICE use per 10k miles. Mainly to just keep it simple to remember the mileage to change it at.

If you plan on changing it every 5k miles / 1 year - sure you can use a conventional 5w20 (which is synthetic blend actually) oil - you'll lose some MPG, but the engine won't be harmed. I prefer to just buy oil on sale and combine with a rebate - Mobil runs one twice a year - then you get the top quality synthetic oil for less than conventional pricing. I stock up on my 0w40 and her 0w16 during the sale/rebate combo (usually Costco or Walmart for best pricing).

 

Personally, I think you could go longer than 1 year/10k miles. I plan to, but few people would agree with me. I think it depends on how careful you are to avoid short trips and abbreviated warm up cycle, both of which can be hard on the oil.

Does anyone even make non-synthetic 0W20? I don't think it would be a good idea, especially if you are trying to stretch the oil change interval. In some rare conditions (usually cold weather), the engine can come on suddenly without warning and quickly be put under load before the car is warmed up.

You could get a used oil analysis at 1 year/10k miles and see how much useful life is left.

I just changed the oil in my other car at 2 years and 6,000 miles. I probably should have gotten it tested, but I didn't think of it.

 

I suggest keep doing what you have been doing, that is every 10K miles or once a year regardless of miles driven by the engine. Remember that the engine components are covered by 5yrs/60Kmiles warranty. If you neglect the oil change and something bad happens to the engine before that time limit, the warranty could get voided.

For food for thought, in this thread, a master Toyota technician @RealCCN suggests oil change every 5K miles even for the Prius Prime that is not driven much on its engine. It is up to you, but it could be a cheap insurance if you plan to keep the car for a long time.
Calling a spade a spade | PriusChat

As for me, I probably will not keep the car that long. Or if even I do, I know the engine will last far longer than the other components that will cost much more to fix. So, I will stick with OCI at 10kmiles or 1 year which ever comes first. For my 2020 PRIME, at current COVID-19 restriction, for the first time in my long car ownership, the 1 year is going to come before the 10kmiles mark.

 

AFAIK all 0W20 is synthetic. If you went to heavier grade, conventional oil is available. I don't know that conventional is "bad" in any way.

FWIW I get bulk Toyota 0W20 (synth) cheap as dirt, from dealership.

 

Wouldn't that be throwing away perfectly fine, unused synthetic oil?

(if you're a cheapazz like me you could bring that lightly used oil home and use it in your yard equipment, if you do that sort of thing.)

As a comparison, a higher tech PHEV, the Volt has an 'Oil Life Monitor' system that allows up to 2 years on the oil,
by regarding how much the engine is used.

 

I would rather pay $20/yr to cover the cost of oil than potentially voiding the power train warranty. But you can do whatever you prefer. It's your car and your money.

 

What's with the 0w16 oil reference in the owners manuals on 2020s. I thought that was interesting, and of course I'm assuming 0w20 Mobil 1 extended range synthetic will be fine.

 

At first I thought maybe this was an attempt to mitigate the cold whether knock issue, but I guess that's a combustion thing. And I'm not sure if that's something that Primes might even be susceptible to.