How low do you let your gas tank get before filling?

[Wallythacker]

I try not to go really low, when everything is blinking I'm heading to my preferred station. I have a preferred place, we all likely do, and I do my best to always fill up there and I know the quality of the fuel I get. If I need fuel out of town I try to find a Shell or Petrocan and neither has failed me. My 2017 is not a fan of Esso, Mobil, Gulf, Husky, or Pioneer. I've read the refineries produce the same product for all the retail stations but I have my doubts of that.

My Saturn prefers Shell, Esso, and a local place in Niagara with many outlets, full serve at self serve prices.

[7milesout]

My Blueberry prefers the cheapest hooptie gas I can find. Around here, and all throughout the Thunderdome, there are Racetrac gas stations. I prefer them. Nice big well lit stores. Lots of crap inside, I get free coffee.

However, there is a brand new Shell being built about a mile from my house. I'm going to just start filling up there. It will also have a Dunkin Donuts inside, I'm gonna just start filling up there too. It's not like I'm lardass enough already...

[Fummins]

I just go where ever. I've never gotten a bad tank of gas(other than stuff that came from the wrecker) but I have had a bad tank of diesel from Shell once. That doesn't stop me from going to shell but I don't go back to that one that sold me watered down diesel.

[Nifty_Biscuit]

I never fill my tank the whole way, I let it go until the last bar (not blinking, just until the last bar is left) and add ~3.5 US gallons, $10USD. That puts my tank at the halfway mark or one bar over. Lasts me 1 week driving to work and back.

I noticed that with a full tank I always get MPG ratings of 35-38 on trips, but once at or under half a tank I consistently get 39-45 ratings. From the dash readout at least.

Someone told me that is bad because "old gas stuff from the bottom of the tank gets sucked into the engine". I find that hard to believe, considering that the pump needs to be located at the lowest part of the tank to pull gas when the tank is low, and the fact that your gas is probably getting well mixed while driving around anyways. Sounds like a rumor oil companies would spread to make us use more gas hauling around more gas.
I could see the fuel pump needing gas as coolant theory sounding true enough.

I'm not a mechanic so I don't claim to know any of that for sure.
I would love to see some knowledge on the subject that isn't paid for by Exxon or OPEC.

Edit: I have noticed from the times I did run to till the indicator was flashing, the car only accepts 7 US gallons max. If the tank is indeed around 8 US gallons, that probably means you have ~one US gallon left in the tank when the bar shows empty. Surely if the fuel pump needs gas for cooling, this is on purpose to ensure the user fills up at this point before problems arise and does not run out of fuel before finding a station

[Nifty_Biscuit]

Well here we go, its all BS. The pump should have a filter, and is cooled by gas running through the motor not being submerged in it

[cleadus_fetus]

So the whole thing where gas is a coolant for the pump is interesting.
I had a '97 dodge neon and in the summer after driving for a while the pump would get weaker and weaker until Id have to pull over.
If I let it cool off it was fine again. In the winter it drove fine.

But having a full tank didnt really affect it that much as the gas was still ambient temperature and that is what seemed to affect it more.

[7milesout]

If the tank is indeed around 8 US gallons

I think the tank is 9.2 gallons. And then there's the fill neck. Trust me when I say, you can run it down to 9 gallons. I've done it, at least twice now. Not necessarily on purpose, but one time sort of.