How often to drain gas tank when only using EV mode

A discussion here said the Prime will run the engine enough to keep the gas from getting stale. Not sure what that equates to in gallons/year. Personally I’m doing one tank per year minimum.
You want to run the ICE periodically “just because”.

 

welcome!
after this tank, just fill it half way

 

I use this, another great choice would be Sta-Bil 360; either will do exactly what you want...



Rob43

 

Doesn't the Prime take care of this for you, automatically? That is, if you drive it frequently, rather than leave it parked for extended periods.

That is bicycling distance, not car distance.

When I get a Prime, its longest 'tank' will be about four months, December through March, when most of my road trips are in the household's higher clearance AWD. The Prime will replace the current Prius as the 3-season road trip car, so gasoline turnover will be fairly rapid during that portion of the year. While no gas needed around town will be great, soaking up my current home solar PV excess, the car will not be corralled to such short distances. It will get plenty of highway distance too.

 

From page 96 of owner’s manual;
Notice about fuel
●For plug-in hybrid vehicles, fuel may remain in the tank for a long time and undergo changes in quality depending on the how the vehicle is used. Refuel at least 5.3 gal.(20 L, 4.4 Imp.gal.) of fuel every 12 months (refuel a total of at least 5.3 gal. [20 L, 4.4 Imp.gal.] over a 12-month period), as this may affect components of the fuel system or the gasoline engine.
●If the vehicle has not been refueled for a certain amount of time and it is possible that the quality of the fuel remaining in the tank has changed, “No new fuel has been added recently. Please refuel” is displayed on the multi- information display when the power switch is turned to ON mode. If the message is displayed, refuel the vehicle immediately.

I don’t think the Prime forces the ICE on after x miles of EV like the PiP reportedly did, but rather warns the driver “No new fuel has been added recently. Please refuel.” How polite. My wife still has some of the origional gas from the dealer in the tank, as we have added 7.7 gallons (spaced out in 6 month intervals + gas stabilizer) during the 11800 miles and 19 months of operation. She can now complete her 16 mile round trip commute plus errands in EV no problem. We do end up using the ICE about 3 times a month, but end up with TOP ranking 999 MPG on the ECO Dashboard (Prime advanced only) most months.

 

I run the ICE every week. I just start the car, put it in HV Mode until the ICE starts and then immediately put it back into HV mode. The ICE will continue to run for a few miles and then shut off. Easy enough to do. Since my memory is mostly jello these days I put a reminder in my iPhone calendar with a repeat interval of 7 days.
J

 

OCD is an epidemic it seems.

Don't make this more complicated than it needs to be.

Just stop forcing EV mode once a year for however long it takes to use up 3/4 of a tank or so and then fill it up.
Adding the recommended amount of stabilizer at that time probably is a good idea.

 

Pretty sure plastic. Take a look? You should be able to see some of the underside.

 

I'm sure I remember reading somewhere a while ago that the Prime engine starts all by itself if the car goes for 200 or 250 miles all in EV. Something like that anyway. But I sure can't find it in the owner's manual.

 

With my commute distance, there is a chance I might get to put it to the test after our vacation trip. It depends on if I need to make any drives beyond battery range. Normal driving doesn't do that, but something always seems to come up.

 

As a new Prius Prime owner, I've been wondering about this too, but with an additional factor.

If you start the engine once every six months or so, isn't there going to be much greater wear on the engine? Long ago I thought I read something that if you started the engine and drove 100K miles, there'd be very little wear, as the engine would remain at operating temperature.

I've also worried a bit about if the engine just starts on rare occasions and then never really warms up with driving over several miles. I just have such a problem forcing the engine to run if there is reserve in the battery.

I suppose it isn't worth worrying about if you've driven 90K miles on electric and 10K miles on the engine, and reduced engine life from 300K miles to 280K miles, but I have to worry about everything.

I'm also wondering if there has been any thought to using 100% gasoline, vs. ethanol blends, as long-term ethanol fuel storage isn't the best practice.

 

Less than if you start the engine every day. There is equal wear on every cold start (assuming similar ambient temperature), regardless of the number of days between starts.

If you don’t need the ICE for propulsion, don’t run it. If you do, run in where it makes the most sense - on the highway, and reserve your EV for around town.

 

Up to a point. If the interval is TOO long so that the engine parts have most of the oil drained OFF of them......then you get the dreaded "dry start" where bad things can happen.
How long......don't know. It probably varies some by engine. Maybe 6 months ??

But to be fair, even then the "extra wear" probably wouldn't be noticeable in any "normal" situation.

 

just drive it, it's a toyota

 

I suspect that most of the oil drains off the engine parts in a day or so. Anything left is tighly adherent and isn't going anywhere. Oil in the bearing journals, for example. Nothing is forcing it out, so it just sits there. As long as there is enough film to protect against a dry start, the oil pump gets oil in there with full pressure within just a few (tens, hundreds) engine revolutions. Particular with very light synthetic oil as used in the Prius.

I have a Miata that sits in the garage from December through March at minimum. I just get in and start it, with no worries.