Calling a spade a spade

Thanks for your sage advice, especially "The main idea is not to treat your Prius as an EV car only." As a PHEV owner, I see a logical as well as a moral/environmental obligation to make sure the engine part of the drive system isn't neglected. It's really 2 vehicles in one that potentially could last twice the normal life of either one. In the normal progression of things, the battery might go down in range to say 5 miles in 20 years, but that would still leave a good battery for HV mode (and a well-preserved engine) to work with for another 20 years (assuming the rest of the car is kept in a decent enough shape).

On the topic of stale gas, one thing I have wondered about is if the fuel pump would draw from the absolute bottom of the tank. I once ran out of gas in my Gen3. Does it mean the tank was totally out of gas or does a bottom most portion designed to hold sediment and water still potentially hold some gasoline? IOW, is there a reserve portion of the tank that is designed to hold sediment, water, etc., that's beyond the grasp of the fuel pump? I would be grateful for factual info from you.

 

My uneducated guess: I doubt it. Just cornering, or climbing/descending hills, probably keeps things very homogenized. I'd suspect the pump intake is as low as possible.

 

My little change the filter before the oil experiment was on the HHR. The day I was going to do the change it started to rain, so I just changed the top mounted cartridge filter. The white filter element was tan, which is how a used one looks for the Sonic and Camry. Which is expected as the visible outside portion is the clean side of the element; the dirt will be trapped on the inside.

Of course the oil was at the black stage. 300+ miles later, I changed the oil. It was no longer opaque black, but a transparent brown. It was likely cloudier than new oil, this was awhile back now, but there no denying the filter took most of the suspended particles out of solution.

Unless Honda filters have much greater surface area than others, I don't see how skipping the filter change is possible if you want the oil on the second change filtered. Oil turns black from suspended soot. It only happens once the filter element is clogged, and the bypass valve open. Is the Honda's first change not black?

 

Yeah it's black. Still, seems like there's black, and then there's BLACK. Our Prius oil changes (around 4K kms), the drained oil is totally opaque/black, but just: oil on the dipstick still looks almost new, just golden. By comparison, on the few conventional cars I change oil on, with oil changes a more normal 5~11k kms, the oil is black with vengeance.

 

Just a possible red herring comment. So, I have a 2015 Honda CRV that gets little use since buying our 2020 Prime. It was 1.5 years since we had changed its oil because Honda had attached a sticker to the windshield that said to wait until the oil indicator said 15%. The indicator said 40% but I brought the car in since we had a 4 hr drive coming. It had been mothballed with a battery tender for six months. Honda changed the oil and inspected the car. All went fine..... until the four hour drive - when three separate warning lights came on - check engine, tire pressure, and key battery.
OK, not really that relevant except maybe the check engine light. Now I have another Honda appointment for the check engine light in a car we don’t drive anymore, but which had just passed inspection at Honda. It makes me believe that it really is unhealthy to keep an ICE engine inactive for six months. This car has been absolutely reliable until now.

 

You cannot tell anything from the color of the oil. If you care, do a used oil analysis:

https://www.blackstone-labs.com/ (popular, laboratory technician provides comments)
More Information for WIX 24077 (cheap but good)
https://wearcheck.com/contact/contact.php (comprehensive but you need to call to get an account)

OIl filters are cheap and they should be replaced with each oil change.

The oil (synthetic must be used) and filter should be replaced every 10,000 miles or 12 months, whichever comes first. You don't need to change your oil every 5,000 miles unless it falls into one or both of the severe-driving scenarios in the maintenance manual. Some synthetics, such as Mobil 1 Extended Performance or perhaps even the vanilla Mobil 1 may last longer (such as 15,000 miles or more) than the others. It depends on the base-oil quality (API Group III, Group III+, Group III+ GTL, Group IV (PAO), Group V (ester etc.), etc.) and the type and amount of antioxidant used.

 

Sir, I really enjoy your writings. I also have learned quite a bit. Your explanation for the 2010-2013 oil burn issue makes perfect sense. I have and will always change the oil in my cars at the 5k mark. Clogging oil holes over time makes perfect sense. Plus having the rings not being strong enough. I can afford the 35 dollar hit every 5k. I can't afford to have my car in the shop for a week, and thousands in engine repair when I could have prevented it. Been there done that and learned from it!! Your answers are honest and you don't talk "down" to us non professionals. Keep the info flowing!

 

I wouldn't be surprised if there is a maximum time between oil changes in the owner's manual.

Assuming you didn't check them during the parked time, the tire pressure and key battery isn't surprising. The check engine light can go off more minor things, like a loose gas cap. A low or dying starter battery could also lead to false codes.

But, yes cars need to be driven. Friend's car wasn't taken on the road for a year, though is was regularly started up and rolled up and down the drive way. Once returned to service, a strut seized up, punched through the top bracket, and pounded a quarter sized bump into the hood.

 

And stale fuel, if any, may have been a factor as well. I have generally noticed that cars degrade if not used regularly, or if all precautions with mothballing aren't taken meticulously.

 

The Critic is a certified and highly skilled mechanic. You can use Valvoline Premium Blue Restore to clean the piston rings.

Valvoline Premium Blue Restore for Oil Consumption Repair or Prevention | PriusChat

It won't repair worn rings though.

 

I Have explained this in John's comment on the video and here and I will happily do that once more. When I said 100% charge I didn't say 100% SOC on tech stream because that's not possible. I meant 100% charge for the consumer on the MID.

Not doing anything and ignoring the charge schedule and basically saying it doesn't even matter. Just charge whenever and do whatever you want to the battery is what I under from your and John's statement of "Owner's shouldn't have to worry about it" and John's comment of "Owners don't need to do anything special when recharging daily." With respect I would like you to explain because I honestly don't understand. Are you telling all Prime owners not to use the charging schedule because it's useless and a waste of time?

Curious on the NCF that you shared. Are you affiliated with Toyota? Sharing TIS documents on a public forum? Terms of T&C No.4? Or is that loosely held? Curious for my own sharing which is None since I don't own a personal license.

 

When your car is totally out of fuel. the lowest point of the tank is actually marked with a circle in the molding of the tank. When tanks are replaced you're supposed to drill a hole there and drain it for disposal. That circle in your Prius's tank is almost in the middle of the tank. The fuel pump is off to the side in your Prius. I don't have a 3rd gen tank open at the moment to see inside but my assumption would be that the fuel pump is close to the lowest point of the tank but not at the absolute lowest point.

Lately with the recent fuel pump recall we've been inside hundreds of fuel tanks one after one to a point where I have consistent headaches from gas fumes! the first 10-20 I intentionally look inside the tank to see the bottom and I'm surprised that it's absolutely clean nothing! Granted they are somewhat newer cars but still after 3 years you'd think there's something. And the filter is typically very clean. The housing for the fuel pump is white and easy to see if there's debris and there's none that I can see. Very impressive!

Other than the recalled fuel pumps which had a problem that's why they were recalled. You really have to be deliberate and intentional to kill a Toyota fuel pump. You won't kill one simply by running the fuel tank empty once or twice. We rarely replace fuel pumps (until the recall of course!) I think I can count the times I've replaced fuel pumps in over 10 years. Water pumps on the other hands different story.

 

I can see old gas throwing a code as it might lead to improper combustion, or the octane has gotten too low. If that is the case, filling with fresh gas should fix the light.

 

I've said nothing about the charge schedule. Could you explain how using the charge schedule extends the battery life over using manual charge? I don't see any SOC setting there, and like most people I do not depart from my home at a precise time of the day so that I could precisely adjust it to ~ 80% SOC. On top of that, the initial SOC varies, and it's cumbersome if not impossible to calculate it even if I did. This brings up my previous point that charging to a specific SOC is not practical.

 

If you read his initial response, you will get an idea. His point is that by using charge schedule as much as you can, you minimize the time the car's traction battery sit with "a full" charge of whatever the real SoC might be. Toyota advocates this practice, and I agree with him. If you don't use the charge schedule and instead use Charge Now all the time and after charging is complete, let the car sit at "a full" charge, which maybe 84% SoC but according to him it can be more than 84%, every day then cumulatively it would have the same effect as letting a full charged traction battery sits for a "long period of time".

 

Really? Could you point me to an official Toyota reference?

As far as I know, there is no trickle charge in Prius Prime; so, leaving the cable connected should have no effect. Also, I thought any battery deterioration would happen during charge, not with the battery sitting at 100% SOC with the charger stopped.

 

It's interesting, thanks. It is basically saying you should have the battery at 0% SOC as long as possible and 100% SOC as short as possible.

I should read all 792 pages of the owner's manual one of those days.

 

Yap, that's my take. However, from what I have read in this forum, letting the traction battery sit at 30-40% SoC is better than letting it sit at 0% (which is ~11% real SoC). Thus, for now not having a daily commute with my COVID-19 restriction, I try to let the car sit at 30-40% SoC and do the charging only if I know I will be driving immediately after the traction battery is fully charged.

 

Charging immediately upon getting home also means you are charging a warmed up battery, as oppose to one that likely had time to cool using the charge schedule. Charge now will mean the battery is subject to more total heat. the system may also not fully charge to battery up in order to avoid excess heat in the pack.