Question about oil change timing and Oil maintenance light

It has alot to do with your driving conditions... In general newer engines and a full synthetic oil can go closer to 10K miles between changes and old engines with cheap regular motor oil can go a bit under 5k miles between changes. But keeping a close eye on what your oil looks like as it gets dirty and starts to deteriorate ought to be more important than what amount of miles is. Or at least once a year...

 

You would think there'd be some intelligence built into the car's recommendations. Throw a plug-in hybrid in the mix....

 

Your premise has a misunderstanding: it’s not an “oil maintenance light”, it’s an indication some maintenance needs doing, at least by the miles.

Toyota USA designates what needs doing in the publication “Warranty and Maintenance Booklet”. Every new Toyota vehicle in the States will have this in the glove box, along with Owners Manual. If it’s missing you can download a pdf version, one source being Toyota Tech Info, under the Manuals tab.

Toyota specs maintenance by miles or months, whichever comes first, which can render the in-dash, maintenance indicator somewhat pointless, especially with low usage where months exceed miles. Canadian spec Toyotas don’t have this indicator, life goes on.

All that said, before the advent of gen 3 (commencing in model year 2010), the Toyota USA spec for engine oil and filter change was 5000 miles or 6 months, whichever comes first. Revising that to 10,000 miles or yearly is not what you’d call an incremental revision, and has met some scepticism. Doubly so with the low-friction piston rings Toyota employed with gen 3, till partway through model year 2014.

There’s been a lot of reports of excessive oil consumption here, and prudent owners are sticking with 5k miles oil changes.

One issue I found with the Toyota USA maintenance schedule, it’s humanly impossible to discern maintenance frequencies, due to the awkward format, that lists what should be done event-by-event. It almost certainly was developed in table format, say with miles/months columns and specific maintenance rows. Then for inexplicable reasons, dumbed-down to event-by-event format.

Another issue is that the schedule stops at 120k miles or 12 years.

Anyway, attached are a couple of Excel spreadsheets I’ve done, reverse-engineering Toyota USA’s schedule back to a more readable format, both as-is and extrapolated to 240k miles or 24 years. Plus pdf’s.

 

Very nice!
Now do a Gen 5.

 

Supposedly, my MINI calculates the number of gallons that passes through the oil pump and lights the service light based on that and I think, oil temperatures.

You'd think that with PHEV, and to a lesser extent HEV engines, Toyota could come up with something more applicable than miles or time. What if you plugged in you PHEV most of the time? Wasn't there a post of someone worried about his gasoline going bad, lol?

 

You’ve got time on your hands, feel free to mod the gen 3 one I’ve attached. I’ve done similar with gen 2 and gen 4, but I’m pooped.

fwiw it’s likely very similar.

@taxce : with the posted, table-format schedules I’ve adhered to what Toyota recommends, nothing more.

I would however recommend these extras:

1. full EGR cleaning every 50k miles, at the least

2. transaxle fluid change, at least once, around 10k miles or 12 months.

3. Brake fluid replacement every 30k miles or tri-yearly. (While Toyota USA says nothing about brake fluid changes, Toyota Canada recommends per this, except in kms)


also, it’s worth noting, Toyota USA does make a vague change in their schedule, that can be missed: most every 5k miles or 6 months they call for visual inspection of brakes, but at 30k miles or tri-yearly, they drop the visual inspection mention, instead say to checking the rotors. I would take the latter as “do a full brake inspection”.

 

You can be sure that they have all kinds of ways of doing realtime technical analyses on the motor oil. But they aren't on the car because they cost a lot to implement, or aren't trustworthy enough, or both.

Miles & time is an easy enough policy for most drivers to follow and for dealer service bays to push. Yeah, you could be saving a few bucks worth of oil per year by paying a lot more attention to finer-grained details... but it's a lot cheaper (in time and effort) to stick to an easy schedule.

 

Is there any reading available of miles traveled where the ICE was running?

 

Never found one, at least in our model.

The book says it can go 10k miles between changes- they are assuming average usage, which itself assumes a certain amount of engine-off travel. I know Toyota has collected and analyzed the stats, even if our car isn't equipped to show me that data.

I've heard a number of mechanics suggesting that a 5,000 mile interval is better. I consider that to be a degree of excess maintenance... but not an unaffordable degree, so I've adopted it.

Penny-pinching future-me may back off of that later.

 

Since I'm in a Prime and do 75%+ in EV mode only; I'm more than comfortable doing full synthetic annual or 10K mile oil changes. Oil is always barely dark brown, never black - like my old diesel. I do the tire rotations and checks at 5K, that's when I can actually read the oil level on the stick. When oil is new, I can't read it on the stick, need to use a tissue to find the wet spot.

FWIW; I use the 20K miles synthetic motor oil formulation, it's only an extra dollar. Remember when jiffy lube recommended 3K mile oil changes???

 

You're supposed to use synthetic oil in the Prius. And for every other newer car out there.
It would be unwise to not use it. It's harder to find non synthetic oil anymore.

You only have to change the oil at 5000 miles if you car about the engine and want it to last.
Going 10,000 or more miles between oil changes is just unwise.

But it's your engine.