Towing range and usuable fuel amount

greatmizzou · July 22, 2020

Hi, finished a long trip to South Dakota and while there I managed 340 miles from Sioux Falls to Box Elder. Towing around 9-10mpg average.

I dont gamble normally but I did there. The fuel meter from 1/4 to empty moves fast! I made it into the gas station on empty and computer estimated I only had 10-15 miles remaining

Refueled with 34.478 gallons and did not "top off". I would say the fuel range estimator was spot on. Sometimes these trucks have 36 gallon sized tanks but people see empty range around 28 gallons or something not even close to listed capacity.

so in summary, it does appear we get full use of the 36 gallon tanks (although I would never suggest you do what I did)

SkidooSteve12 · July 23, 2020

Nice!!

I have gambled when towing a trailer with my old 2005 3/4 ton and ran out of gas about 1/2 mile from the gas station I was planning to stop at. I think that was the only time I have ever run out of gas and it was because the trailer lowered my MPG more than I was estimating.

We just got back from a vacation with my 29' inline trailer hauling my FIL's UTV's and I carried 10 gallons of gas with me. We were spending a week on an island and I just wanted to be prepared. Well on the way home we got off the highway and the gas station and restaurants were a zoo, so we decided to hit the next exit for gas. Pulled in and they didn't have power! haha I was under a 1/4 of a tank and could have made it to the next major exit where we were going to eat, but I was already in an empty parking lot so I dumped in my gas cans.

I've put in over 32 gallons quit a few times, but was just city driving at that point and had a plan to fill up at the cheapest gas station!

Pfc1 · July 24, 2020

Talk about cutting it close, the lowest I've gone was an 1/8 tank. The fill up was around 32 gallons so definitely pretty accurate gauge anyway, I didn't look at the miles remaining but I did notice that miles remaining is based on the current fuel economy, if any of that helps.

Ray Pickle · July 24, 2020

I often fill up locally between 32 and 34 gallons, to maximize rewards program. $1.00 off up to 35 gallons.

greatmizzou · July 24, 2020

1 hour ago, Ray Pickle said:

I often fill up locally between 32 and 34 gallons, to maximize rewards program. $1.00 off up to 35 gallons.

Do you think that may cause fuel pump issues in the long run? Ive heard mixed concerns that low fuel will cause fuel pump to heat up and not cool

diyer2 · July 24, 2020

You can believe the fuel keeps the fuel pump cool or not, your choice. I will add this.

Was at a dealer parts counter buying a new fuel pump for my truck. The parts guy asked how many miles were on the truck. I told him. He said you don't run your gas tank low do you.

Ray Pickle · September 17, 2020

Fuel does certainly provide some cooling to the fuel pump and over the long term may cause it to fail slightly ahead of one that never sees less than 1/4 tank. I choose to save an additional 10 bucks or so per fillup than worry about when my fuel pump may fail north of 100k. I figure I will have paid for a couple of fuel pumps with the savings. Further in my professional observation I have not observed premature failures of fuel pumps attributed to clients fueling habits. It is talked about a lot by tech trainers but in practice I can't back that up. I have been in the field for 40 yrs. and counting.

Chris Eaton · October 25, 2020

Funny to run into this topic today...was towing our camper home this morning, gambled....pulled in for fuel, was able to pump 35.1 gallons....yikes.

2020 GMC Denali 2500HD gasser

spm1us · October 26, 2020

I guess it depends on your local climate but in the sweltering heat of Florida, where it’s above 90 ten months of the year, it DEFINITELY causes premature failure and shortened fuel pump life as the gas in the tank constantly recirculating helps cool the fuel pump motor. You pays your money and you takes your chances!!! A fill-up at half tank or slightly less is cheap insurance and is a simple insurance especially considering gas is less than $2 a gallon.

Davew277 · December 16, 2022

Fuel pump overheating aside, if you run your tank that close to empty your fuel pump will also suck up all of the contaminants that were floating around on the top of your fuel, which will lead to other issues.

Most vehicles I have owned recently showed empty when there were 2 gallons left in the tank. If these trucks show empty when it's actually empty then that is good to know and I'll not run them that low.

I always carry extra fuel with me, especially because I travel a lot. I'm currently 1,100 miles from home and I have 67 gallons of reserve fuel with me. When combined with at least a few gallons in my tank I have enough to make it home on my own fuel, if need be.

I'll be putting a 100 gallon transfer tank in my new 3500.

sheath · December 18, 2022

I'm a fan of filling at or before the 1/4 tank mark. Just not worth the stress to me, especially when pulling a big trailer. My average fill is just under 30 gallons.

Nice to know that in an emergency, I could squeeze out another 35-40 miles when towing though. So thanks to the OP for posting this.

Pryme · December 19, 2022

I’ve always been a believer in the fuel pump keeping cool in the fuel so I personally like to just fill up sooner than later.

Jettech1 · January 21, 2023

If you look at how fuel pumps are designed, they are lubricated and cooled by what they suck up. Having extra fuel in your tank does not help that motor at all. Having said that, I'm the 1/4 to 1/8th of a tank guy that can't handle the needle being that low. It has nothing to do with fuel pump life, it has everything to do with what I personally am comfortable with. Any contaminates in the tank will be sucked up at a very high rate due to the high fuel pressures these days and will be shoved into the fuel filter first, before it goes into the fuel injection system. Many years ago when the fuel pump was operated off a lobe from the cam shaft that was attached to the engine block, contaminates were an issue. These days with high pressure fuel pumps and filters, that worry is gone. Edit: The only time you want to keep a full tank all the time is in extremely cold weather to help offset condensation that is building up in your tank due to massive temp. swings. No one wants water in their fuel, so for those that live in cold climates, a dose of HEAT, basically alcohol, is great to use. Alcohol is pretty much the only liquid that will actually mix with water and help it burn. Weird factoid that most know that live in really cold climates.

Edited January 21, 2023 by Jettech1