2004 Prius "Bladder" Question

Size of the bladder doesn't vary the flexibility of the bladder does. In the winter the bladder is less flexible and makes fueling the Prius a challenge. I learned real quickly after I bought my new 07 that the bladder was very unhappy if you just opened the gas cap and tried to shove gas into it.
It would shut the pump off repeatedly.

The bladder is held to a vacuum when the car is in READY. This collapses the bladder around the liquid so no air void =no fumes created. One of the many ways its reached its Zero Emissions mission.

Best and easiest trick to drama free fueling in a Gen 2 is when you arrive at the pump open the gas cap and go inside the store and allow the gas tank to vent for a minute or 2. This venting relaxes the collapsed bladder and the bladder will open up releasing its air pockets. If not allowed to vent your basically trying to fuel into a collapsed bag with trapped air pockets. The pump senses that back pressure and shuts the pump off.

This venting and relaxing of the bladder takes a lot longer if its very cold out and the bladder is stiff and is almost 10 years old. It may help in the winter to not let the gas get to low. Very low fuel level will increase folds and trapped air pockets in the collapsed bladder. Personally I would not let the gas tank get below half tank in the winter especially on an older car like yours. The bladder will not be so collapsed and easier to vent.

Inconvenient I know but so is not being able to put gas in the car standing there in the freezing cold.

 

Devils advocate here
When we open the gas cap and let the bladder expand while we get coffee, aren't we venting gas fumes?
This somewhat defeats the purpose of the bladder.
Honestly, I too am guilty venting occasionally...

 

Yes you are absolutely defeating its emission mission. But its a pretty bad design they fixed in the G3. No bladder in G3. The schematic for the fume recovery in a G2 is incredible. They got really carried away.

But sometimes its next to impossible to get gas in the bladder unless you let the car vent a little. And to make matters worse sometimes if you gas immed and not vent and dump gas in real fast and the pump shuts off and then realize ok I need to vent a little its too late. You've put gas on top of air pockets. You can vent all you want then and pump still shuts off.

So you have to vent from the get go. I'm not happy about it but it works.

 

What's really trippy is when you fill - and the fuel pump auto-shutoff is broken. Refilling our '04 at costo - and holding the nozzle tightly against the filler neck - I looked at the pump to see how many gallons I'd taken. It said about 10 gallons - but the tank already had som gas when I began. I shut the pump trigger off and pulled the nozzle out.
WHOOOSH
The Prius vometed gas - looking like Linda Blair in the Exorcist

so - be aware

 

Pretty obvious whats happening. Nothing wrong with the pump.

Pumping gas fast into a almost completely empty collapsed bladder. Suddenly bladder unfolds and releases its trapped air & forces gas back out the only way it can.

 

...we never had a problem filling up from empty in cold weather on our 2006. But we definitely get less gaso in the winter...about 8 gals.

 

I have an '04, and I just ignore the bladder. This works fine for me.

 

... let me help you understand the bladder a little bit. There've been several posts over PC's years of existence regarding the gen 2 Prius bladder. The bladder does not collapse like it sounds you're saying. It does not unfold. It has no similarity to a collapsed hot air balloon. So let's get that image put to bed. Here's a photo that will help folks understand the nature and shape and texture of the bladder. It's actually quite rigid;



PC's hybrid Tech was nice enough to remove the bladder from its rigid case. If anyone is interested you can check out the thread he posted with many other pictures included here:

the gas bladder: exposed! | PriusChat

I hope the link is helpful for all those folks who would like to get a better understanding of the Gen II Prius ladder.
ENJOY!
.

 

Thats not the bladder thats the bladder case. There is a flexible inside to it also.

 

I'm guessing you didn't bother too look at Post ONE of the link above? with all the photos of complete gas tank dissambly? . . . . in stead, you're saying there's a bladder, inside the bladder, inside the steel tank? Please enlighten me - perhaps a link? photos? ANY source to show what you're talking about? And what's the purpose for having a bladder inside a bladder inside a steel tank?
I'm just asking because what your'e saying flies in the face of what galaxy's 'DH' says. Did you notice I mentioned he's a Prius specialist? one of Toyota's hybrid techs? ... and that the last sentence below his post / pictures of the gas tank/bladder link - showing all the assembly photos - it says:

yet, I suppose I could just be confused, and somehow missed it after all these years, and simply can't find any exploded view showing another bladder inside the only bladder I've ever seen in any Prius literature.

.

 

...yes and I have to replace my "like" onto the correct poster...whomever that is

 

No you're right. I mistakenly keep thinking there a flexible bag but there isn't. I remember now seeing Galaxee's pictures years and years ago. The one's you posted here.

My pocket theory is a bust. But it must have to do with the vacuum and the tanks inability to purge it quickly enough for the people including myself who have had to struggle with filling the tank and have had gas belching episodes.
Venting has fixed that. For years now.