New (used) owner I like the car but...

Yes, I get gas at 400 miles every time. Don't cut it too fine. (I am a one click kind guy, I own a Prius for clean air, not MPG)

When you turn the car off, it pumps three quarts of coolant into a thermos to keep it warm, when you start it again, it pumps it back. (I hear the noise after stopping more)

 

The -potential problem- with topping off is the fuel system is closed. That is, the bladder is supposed to accommodate the expansion of the gasoline from temperature variations and minimize the vapour volume (vapour plus air) in the tank.

If you -fully fill- the tank with gasoline, there is no place for the fuel to go if it expands. It usually does, as it's stored underground at about 50 F, and in your area air temp is usually 80 F or higher in the daytime. So the fuel will expand, force its' way through the carbon canister and pop off a vapour recovery tube -inside- the fuel tank, discharging liquid gasoline in there, but outside the bladder. The car will sense this "leak" and throw a code, requiring the tank be replaced. There goes $400.

So, if you "top off" be very careful to leave -some- expansion space. My calculations indicate 2-4 quarts is enough. If you go too far, leave the cap on loosely to allow fuel to escape if necessary, until you use enough to give you some expansion room.
Obviously, great care should be taken if "topping off", as the "fix" is not desirable, either replacing the tank or dribbling fuel into the environment.

To answer your original question directly, think about getting fuel when you get down to two or three pips. Get fuel when you get down to one pip. GET FUEL NOW!!! when that pip begins flashing!

 

Third Camp: I fill it at full pump speed until I get the first click release, then I resume at a lower speed until it clicks again, then I stop. Seems like a good compromise.

 

I always fill at low speed until the pump clicks off, and then stop.

The numerous and heated postings about filling problems are because a minority of Prius owners have experienced problems refueling. Most of us have no trouble, and simply fill up like we would with any other car. The problem is that for those who do have refueling problems, the problem is very frustrating, and not easy to fix. This has caused the numerous threads about the problem and some rather heated exchanges. If you don't have a problem, you won't have problems. If you do, try some of the tricks.

Tom

 

Wow. I didn't even know there was an issue. Good thing I found this thread. I typically loch the pump in the FAST spot and when it clicks i am done. I never top off on my own. And in states that pump gas for you I alswyas just ask to not top it off.

My reasons for this were actually for more consistency in tracking my MPG Where given the millions of gas pumps being all different, i would hope to be close when they click off LOL

But now realizing there "could be" a potential problem with pressure. Well, hopefully i am still good by letting the pump do it's quit at it's time. Other than that I don't know how one could effectively know when to stop pumping gas in any quantifyable measure. This mainly due to the fact you never could know EXACTLY how muhc fuel you used, and how much capacity is left to fill up.

So I hope the pump can be relied upon

 

As stated, if you don't have a problem you won't have one. Sometimes a pump is too sensitive. Either it will pump a bit & stop--repeatedly or it won't shut off resulting in spillage if you aren't standing by the fender. I prefer slow but the attendants always use fast. I don't say anything as it still works. I believe in 3 years I've had 3 pump problems. Volume is erratic, hence the "guess gauge". Believe it only at the low end.

 

There's no big issue, at least not for the vast majority of owners.

Don't go for max fill. I always I stop at the first auto stop unless it seems like the pump has stopped way too early for some reason, which I'd guess is <10% of the time. If it's seemingly stopped early, I either do 1 click or 2 more clicks max, esp. if it seems I should be close to full.

See http://priuschat.com/forums/gen-ii-prius-technical-discussion/30593-gas-bladder-exposed.html and http://priuschat.com/forums/gen-ii-...shooting/29844-confirmed-overfill-damage.html as to why.

IMHO, don't screw around w/trying to multiply what you see on the MFD x what you put in last time. You're bound to run out of gas doing that at some point. Strongly consider getting gas when you're at 2 pips and get gas pronto at 1 pip.

Looking at my records, I've never put in >9.975 gallons and that was my 1st tank. I always try to get gas at no lower than 2 pips. The longest I've gone between "tanks" is 434.5 miles. (Sorry, my lifetime avg is only a bit above 46 mpg.)