# What the lowest you run your tank



## mr overkill (Dec 1, 2013)

what the lowest yiu run yiur fuel tank ???


I just put in 13.9 gallons. OOPS


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## MRO1791 (Sep 2, 2016)

A big fill for me is about 10 Gallons. It's best to not run that tank below 1/4, since the in tank fuel pump is cooled by the fuel in the tank, as such when it's low, that pump can get hot, which shortens its service life... Now an occasional low tank won't kill it, but it's best to avoid... and given the range on even 3/4 of a tank is still about double most gasser cars, it's not much of an inconvenience to fill it early.


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## phil1734 (Aug 30, 2019)

I rarely put in much under 12. 13.9 is pretty impressive. I'd think that'd be just about as close to dry as possible.

The urban legend about running your tank low is one of the most infuriating myths to me, right after "warped" brake rotors. Not only are pumps cooled and lubricated by fluid running through them (not being submerged in it,) but they also _always_ pick up fuel from the bottom of the tank where sediment would collect. If they didn't, they'd never empty the tank.


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## MRO1791 (Sep 2, 2016)

phil1734 said:


> I rarely put in much under 12. 13.9 is pretty impressive. I'd think that'd be just about as close to dry as possible.
> 
> The urban legend about running your tank low is one of the most infuriating myths to me, right after "warped" brake rotors. Not only are pumps cooled and lubricated by fluid running through them (not being submerged in it,) but they also _always_ pick up fuel from the bottom of the tank where sediment would collect. If they didn't, they'd never empty the tank.


No "urban legend" about it. Whether to fuel flows inside the pump motor, or not, the lower fuel level provide less heat absorbtion capability, and on turns the uncovered pick-up an suck up some air, which will certainly not transfer away heat as well as fuel flowing though. The concern is the breakdown of the coil winding insulation in the motor due to heat generated there. Now the many stories of these types of pumps failiing and with people who freqenntly run down to E, and yet many others who rarely do, and have their pumps that last well over 20 years speaks for itself.

Oh, and I should also add, the motor has to work harder (more current) as the level in the tank goes down, due to lower net positive suction head for the pump, so not only does it become surrounded by air that transfers away heat less effectively than fuel, it is also generating more heat in that conditon.

Feel free however to do as you wish.

Here is an article with details and diagrams on how modern fuel pump modules work: 






AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What Causes Fuel Pumps to Fail


AGCO provides overall lowest costs of vehicle ownership. We do this by providing extremely high quality automotive service, following the theories and practices of Dr. W. Edwards Deming., what causes fuel pumps to fail




www.agcoauto.com


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## BodhiBenz1987 (Jan 13, 2018)

The most I have put in was just under 12.3. Usually I put in between 10 and 11. A lot of times I just fill up early so I don't get stuck using an unknown station or having to stop somewhere inconvenient. Plus I just don't like taking chances, since the range can change really fast if I have a regen or get stuck in bad traffic.


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## 6speedTi (May 18, 2018)

Lowest I ran my diesel was at sea level. 🤣


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## johnmo (Mar 2, 2017)

My biggest fill is 13.473. Traveled 773 miles on that tank. I almost never fill before the fuel light comes on.

I have 13 or 14 tank fills over 13 gallons and more than I care to count over 12 gallons.


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## Diamond193 (Jul 28, 2019)

Is it best to stick to the same station for fuel ? I use premium and have been going to the same station for months because they sell premium the cheapest


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## Barry Allen (Apr 18, 2018)

MRO1791 said:


> It's best to not run that tank below 1/4, since the in tank fuel pump is cooled by the fuel in the tank, as such when it's low, that pump can get hot, which shortens its service life...


This advice applies to basically any vehicle manufactured since the mid-1990s. As soon as they switched to in-tank fuel pumps, you'll see early failures with drivers that run it down to "THE LIGHT IS ON!"


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## Barry Allen (Apr 18, 2018)

mr overkill said:


> I just put in 13.9 gallons.


Just yesterday I filled up with 13.825 gallons. That's filling all the way up the filler neck after repeatedly allowing foam to settle. I do this for consistent fuel economy calculations on the spreadsheet.

I stretched that far because I was approaching a state line where diesel fuel was about 30-40¢ cheaper per-gallon, and I went to a branded station that both accepts my grocery store fuel points and Apple Pay for 3% cash back on purchases.


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## Barry Allen (Apr 18, 2018)

6speedTi said:


> Lowest I ran my diesel was at sea level. 🤣


I've been to Death Valley, so I have you beat.


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## Barry Allen (Apr 18, 2018)

Diamond193 said:


> Is it best to stick to the same station for fuel? I use premium and have been going to the same station for months because they sell premium the cheapest


"Premium" diesel has no definition in trade regulations, so who knows what you are getting for what they charge you.

In the past 15 years it is almost impossible to get a "bad" tank of diesel fuel. EPA regulations for ULSD means the refining of diesel fuel is so far beyond what you could get in the 1990s that it's all the same. It's a commodity delivered from refineries to stations, and maybe they put an additive package in it but unless you physically see them doing that you can't trust it.

Buy any diesel fuel and add some Power Service.


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## Diamond193 (Jul 28, 2019)

Barry Allen said:


> "Premium" diesel has no definition in trade regulations, so who knows what you are getting for what they charge you.
> 
> In the past 15 years it is almost impossible to get a "bad" tank of diesel fuel. EPA regulations for ULSD means the refining of diesel fuel is so far beyond what you could get in the 1990s that it's all the same. It's a commodity delivered from refineries to stations, and maybe they put an additive package in it but unless you physically see them doing that you can't trust it.
> 
> Buy any diesel fuel and add some Power Service.


My cruise is not a diesel I guess I posted in the wrong section


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## Snipesy (Dec 7, 2015)

Barry Allen said:


> In the past 15 years it is almost impossible to get a "bad" tank of diesel fuel.


At the refinery, yes...

From there on it’s pretty bad. It’s common practice to see towels around valves to stop them from leaking. When spills happen the workers are told to just bucket it up and dump it in the tank. And if they do report a spill they’ll likely get fired.

Illegal? Yes. Very. But no one cares.


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