Gasoline additives needed if Prius Prime is mainly driven in EV mode?

If you stick with one of the "Top Tier" brands of gasoline and burn a tank a year you'll be just fine.

 

If you are concerned you could add some Sta-bil fuel stabilizer.

 

No. The tank is pretty much a sealed system and the fuel won't suffer in 6 months. And, when you need to refuel, just put in 3 gals at a time until just before you head out on a road trip, then fill it.

I came back from a road trip on May 16 with about three bars on the fuel gauge, and yesterday (June 30) I put 3 gals in. That's 1205 miles, probably 400 on the road trip and the rest since then.

 

But make that "some" read "the recommended amount".
Then put in more stabilizer ONLY as the tank full is pretty much used up.
Too much stabilizer can cause troubles too.

Most people in most situations do not NEED to put in any "fuel additive".
The car is programmed to not let you drive around with the same gas in the tank for a year or more.

 

congrats and welcome!
i have never added anything to my gasoline. what kind of additives are you talking about?

 

I would do whatever the manual says,

but Generally no OEM will list gas additives, they simply aren’t useful on a modern car

 

The Prime isn't like a 2-cycle gas lawn mower. As long as you burn through the gas once a year (as noted in the manual), no additional additives are needed.

However, you may consider using up some of that gas so that it isn't 4-6 months of dead weight, bringing down your EV efficiency.

 

And then you have weird people like me who almost a year and a half later (and over 9K miles on the clock) still have 1/4 of the original dealer tank to go. Perhaps an extreme when compared to the broader demographic of prime users but so far no issues to report.

Cheers

 

Just curious - why did you buy a Prime instead of a BEV?

 

Signature says they have a Model S so maybe the Prime is for trips to places with no chargers in the great white north. Just a guess.

 

If that were the case, then you would not see 3/4 of a tank used in 9K miles. Any long road trip in a Prime is going to burn mostly gasoline.

 

How does the Prime know the length of time gas has been in the car?

 

Because the Prime is the closest thing to a Toyota BEV one can buy in North America. Having a fair bit of experience with BEV's in my part of the country also allows me to appreciate the more subtle qualities of a car like the Prime. Super dependable and reliable. And definitely the most efficient given my location and usage which makes it a worthy daily driver instead of just another weekend toy.

 

The volt monitors the exact fuel level and when you fill calculates the average fuel age.

My guess is Toyota does something similar monitoring the fuels age so it gets burned off occasionally

 

On-board clocks and computers.

 

I'd hope it's not that simple as that would be too easy of a hack for those (few) who refuse to buy gas. I inadvertently pop open the fuel door on my PHEV's while cleaning the dash with a large rag as I sweep across all the buttons.

My guess is it would have to be a combination of the fuel system depressurization and gauge level changing.

 

I would use all the fuel additives mentioned in the owners manual: None.