I always keep one tank full. Ya never know when Somali PSD Pirates might strike.
Plus....it's just piece of mind. If I'm on a trip then I run them both pretty close to empty.

Rog

 

There's some validity to the trash argument. Not all trash sinks to the bottom. It may either float or be suspended in the fuel, and sucking the last remaining drops out of the tank will force that debris to the suction point. Most tanks do stay clean, so this typically isn't too big of an issue.

The main reason this advice has been handed down for generations is the distance to the next fuel station used to be longer than it is now, and on older vehicles, when the needle hit E, that meant it was time to walk. I was always told, when the tank gets to 1/4, it's time to start looking for a place to fill up. Take a trip out through the middle of nohwere sometime. Knowing you can make it another 30 or so miles doesn't help if the next station is 60 miles away.

This advice made a resurgence when the introduced unleaded gas since it was hard to find for a while. It should have become popular again when ULSD was introduced for the folks with the 08 trucks, but when I tried to point out to several of them they were putting LSD in their truck they looked at me like I was stoopid. (I waited till after they finished filling up then asked if their truck didn't have a sticker that said ULSD only, and didn't the pump they just filled up at say not for 2007 or newer vehicles. Then said, hope Ford doesn't void your warranty, have a nice day )

 

My thought on the possible junk in the tank (as opposed to junk in the trunk!) is that I would rather deal with it a little at a time by sucking the tanks down each fill up. What happens if you never go below 1/4 tank then have to go below that in a pinch. Then you have all the "junk" that could cause you issue when you can't afford any issues.

 

I'm like TJ, run them dry. I do have the security blanket of an auxiliary tank that's a bitch to fill up, so I usually leave it full.

 

I'm like Jeep & a couple of others. I run my down to 1/4 tank then switch over to the other. No particular reason, just have always ran my trucks like that. A little safety in the tank never hurts either.

 

I've only run a tank dry one time. It took me forever to get it started again so I don't repeat the exercise. I do run one tank all the way to E and a little past then switch over. I try to keep at least 1/4 tank. Part of that is that I'm 20 miles from a station, so if I go below 1/4, I'm pushing it when I get back to town.

I don't entirely buy the junk theory. Even if there was some truth to it, I'd want the stuff in the filter. That's the whole point of the water / sediment filter anyway - collect the stuff and drain it off.

 

+1

this is what fuel filters are for....catching the crud. unless i am out in unfamiliar territory, both tanks get sucked down close to E before filling.

 

Back in my HS days a buddy of mine had a Chebby with dual tanks and it was his habit to run a tank clear out then switch over. One day on the way to school it started to sputter so he hit the switch,, and it kept on sputtering until it died and there we sat, dead on the road with a full tank fuel and a tank switch that had just gone bad.

I switch mine over at 1/4 tank

 

I agree with the whole 1/4 tank thing, because i have learned from expierence that fuel guages can lie and when you think you have an 1/8th of tank your really on empty. Both my Old 88 Blazer and 86 F-350 6.9 were the same way and i'm sure we all know how hard it can be to re-primp that old 6.9 diesel. With that said i run my F-250 to almost empty because i dont always have money to fill the tank since i'm in college. (and a side note my rear tank on my F-250 starts to suck air at a 1/8th of a tank, need to fix that.)

 

because if you sucked fuel off the very top of the tank you would "run out" of fuel after youd only burned about a gallon. look at it like a straw in a drink. if you pull the straw up to where the bottom of it is at the very top of your cup you arent going to get much drink after your first sip or two.

 

And it would be better to be on the side of the road with one full tank and the other 1/4 full?
With my gasser, I used to run the first tank DRY then switch. With the diesel I have run each of them dry but recovery takes too long so I go until the needle is BELOW empty then switch.
Never lost a fuel pump because of it & never plugged up a filter from it.
Done it that way for over 800,000 miles on 3 trucks.
With only one tank on my Expedition, I fill up somewhere below 1/4 depending on if I am on a trip or just getting back from one.

 

That is the way I do it also. My thoughts are if I never used that last ¼ tank then it keeps filling with crud and water. Eventually it gets too much over many years of use and gets sucked up... and alot.

If I use up every tank till empty then each tank gets rid of the "nasties" and the filter gets to do it's job. In turn the tank stays cleaner.
Maybe that means more filter changes but in my mind the more filters the better.

There it is, it's official, Ya'll now have my last two cents!

 

Yea, same here. If you do this the filter will work the way it is meant to. It will get a little gunk from the bottom of the tank every time you go to E. If you only go to 1/4 tank the crap will just keep building up at the bottom of the tank and then when the inevitable happens and you run it down toward empty the pickup tube will get buried in the crud and clog up every thing all at once.

 

The pickup tube is just below the float. When the float drops down with the level of the fule so will the pickup tube.

 

See my last post.