how much fuel to keep in tank?

That's where I usually wait to fill it too.

 

At least with my car, I go consistently 50 miles past the "empty" point. I still have more than half a gallon to put in.

 

I'm inclined to go through most of a tank rather than top off, out of concern for fuel going stale. This isn't a major concern if you drive a lot, but unpreserved fuel starts to degrade in a couple of months.

 

Funny, just recently I've been seeing how far I can push it.
Potentially dumb, I know.

But when the light blinks, we allegedly have 3 gallons left.

I've pushed it to 430 miles so far. Most fuel I've added is 9.4 gallons...so I could have gone significantly further it seems.

 

I still had ~2 gallons left when the light started flashing. I usually fill at 2-3 though as I hate not having gas if something were to happen

 

You aren't thinking about the C... the C only has a 9.5 gallon tank, so not significantly farther than 9.4. We only get ~1.5 gallons after the beep.

 

Noted.

 

That's another "fact" from a long time a go. Fuel retains is qualities/properties a LOT better than it used to.

 

I'm Googling and finding various opinions. FWIW, here's a report that seems to carry some authority:

CNN: Can Gas Really Go Bad?

And of course there are fuel stabilizers out there, the most popular being Sta-Bil

 

I forgot to check back in this thread so my apologies for the very delayed reply. That article does cover the bulk of the knowledge that I am aware of.

The current engine management tech and level of sensor sophistication is so far advanced even compared to 20 years ago is a big part of what makes "old" fuel less relevant.

Since I live in Ca and we have diff. fuel for just about every season and there never seems to be enough fuel made that I doubt the fuel you are buying is more than a week old tops in this state.

It's been too long but I recall reading an article that said even though there was 3x as many cars on the road today compared to the 60's there is only half the gas stations. The end result is you are less likely to have a station sitting on "old" fuel.

My personal experience is from my motorcycle that would sometimes sit for 1-8 months at a time with a partial to full tank and never have had an fuel issues with either the carbs or the FI bike.

Travis

 

If I know its going to sit with a full tank I'll put stabilizer in it since ethanol crap based gas starts to phase separate in a few weeks. I also don't want any vapor condensation rusting up an empty tank, a carry over from my motorcycle days.

 

Bladders in aircraft keep the tanks from filling with vapor and swishing around not to mention handy if your shot up. WW2 Zereos didn't use these, that's why they go kabomb on all those vintage films, oh they were made out of wood too.

 

That mechanic is correct but it depends really on how long the upper half of tank isexposed; you can easily get by with being in the last 2 gallons if its not going to be there more than a day. its a good idea to keep the tank above 1/4 tank simply because the pump is more efficient there. Running the fuel pump dry even for a short time does stress the injectors and pump.
BTW the pump does not cool the gas tank. The gas cools the pump and if run hard enough long enough the gas in the tank would get hot. letting the tank level get low enough to expose the pump (when the gas is low and centrifugally pulled to one side) the pump can overheat and even blow its fuse.

 

In answer to the question in the title, I keep ALL my fuel in the tank. There really is no other safe place for it.

Sorry, back to the good advice others are giving.

 

Just make sure you dont run the injectors on air; they will fail if you do more more than a few seconds.

 

Big oil must be laughing so hard their crying when they hear fill up early & often, anyone know if the fuel cools the pump from the inside out (cools the pump as it runs regardless of the amount of fuel in the tank) OR from the outside (needs fuel in the tank)?

 

If you live in an area that can have evacuations due to weather (hurricanes, blizzards, flooding), fires, earthquakes, volcanic eruptions, etc., then it is best to keep enough gasoline in the tank so that you can "bug out" without having to find a gas station and deal with gas shortages. I would try to keep half a tank or more so if you need to "bug out" you can do so quickly. You only need to get caught in a huge traffic jam once with your car on E to see the wisdom in that. When hurricane Rita was heading to the TX/LA border just weeks after Katrina hit, the Houstonites panicked and clogged up the highways exiting the city. This resulted in a lot of cars running out of fuel on the highways. It was not uncommon to take 10+ hours just to get out of town in the panic since the highways were little more than parking lots!

I personally do not live in an area where evacuations would normally occur. However, I tend to keep my tank at least half full because if I get a call in the middle of the night wherein I have to hurry off to a relative or friend's home because of some kind of emergency, the last thing I will want to do is waste time by stopping to fuel up.

 

Rather than depend on the tank, I keep several 5-gal cans of gas stored for emergencies. Got a system: When I fill a tank, add Sta-bil preservative, and mark the date. A year later, use the gas, refill, and preserve again. So I'm good to go, whatever state the car's tank is in. Also, can take advantage of the fact that a hybrid and a sine-wave inverter makes an efficient emergency generator for a few hundred watts. When the apocalypse comes, I can sit around for a couple weeks playing video games and shining bright lights into the face of zombies and generally have a good time until I'm overrun. I just hope, when it hits, that I've got the car at home or can get it home.

 

I NEVER GO BELOW A QUARTER TANK, but that's just me..............

 

Why would they be laughing? It's the same fuel, the only difference is the time spent pumping.

Most fuel pumps are cooled outside by the gas in the tank, not by fuel running through it (although, this probably doesn't hurt).