Low Diesel Fuel

[Fulltilt]

So I have a 2018 Ram 3500 HO Cummins/Aisin, 3:42, Crew Cab/Short Box, hauling a 15,000# 5th wheel. Yesterday travelling south on I5, I had the "expected" low fuel light come on at approximately 50 miles "range remaining", I wanted to push to my destination which was 24 miles out, where fuel is fresh & reasonable, & also where I was spending the night. I had travelled 278 miles, by the time I pulled up to the pump, the fuel needle was in the red. The truck only took 27 gallons of fuel to click off, if 32 is the accurate capacity for our 3500, [or am I mistaken ?] do I have 5 gallons of reachable diesel left, or is it accurate to say that 27 gallons is all that is useable ? Thank you

 

[mtnrider]

I think the tank is actually 31 (but have seen 32 claimed as well). I have never taken mine past needing 28 to fill so not really sure? Given you had weight "sagging" the truck slightly might affect it as well. Regardless I wouldn't push it past that as you need some fuel in there to keep the pump cool and you don't want to run it dry.

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[Travelin Ram]

Almost every vehicle I’ve owned has significant fuel in the tank even when run all the way to E. For a couple of reasons.

Cooling for the in-tank pumps.
Car makers prefer to err on the side of caution, because if it ran out 1/10th of a mile short of what the dash said, some Karen would hire a lawyer and sue.

Most of my full size trucks have had approximately 4 gallons remaining at “empty”.

 

[mtofell]

Yeah, this was a common complaint when these 4th generation trucks first came out and was talked about a lot here. I think the general consensus is the gauge and miles-to-empty is not accurate and leaves a lot of remaining fuel to keep the pump submerged and to keep people from running out. I don't recall anyone ever reporting running out either accidentally or by testing it. It would be nice to know... or better yet have an accurate gauge and let me watch out for myself.

 

[ibike]

When my 2015 Jeep Wrangler would get a low fuel light there is 4 gallons of fuel left. 18 gallon tank and all I can refill it to is 14 gallons. Just an example.

 

[KoboldTaco]

It’s a modern reserve system for all of us who like the OP, prefer to make it to the next station vs. pushing their rig...No petcock to rotate to reserve and likely not many of you running out of gas when on E.

Looks like the mind game continues to work

 

[62Blazer]

These are set really conservatively. The biggest comment above is that if it actually stopped running before the miles remaining was at zero some people would throw a fit. Here are my other comments:
The "miles remaining" is just an estimate based off of recent driving style and the associated MPG. Think about if you are cruising down the road at 55 mph and thus getting really high MPG, and then all of the sudden start driving in a way you are getting substantially worse MPG.
You have to take into account fuel slosh. Simply going around a long curved interstate off-ramp could cause the fuel to slosh away from the pump pickup, or if you stop in a parking lot or something at a steep angle.
The only thing I don't really agree with is the comment about having fuel to cool the pump. Don't think that is an important design aspect when setting the low fuel level. If you think about it having 4-5 gallons in a bottom of a 32 gallon truck tank it's probably only a couple inches deep, and definitely not deep enough to fully submerge the fuel pump.

 

[Dhendrickson]

I have a 22 mega cab short bed that was supposed to be 32 gallons and also can only get 27 to 28 gallons in it. I thought it was just gauge not accurate but I tested it out one day and after running approximately 5 miles past empty while towing I ran out of fuel and I was only able to get 28 gallons in the thank then.

 

[06 Dodge]

Owners Manual list a 2022 meg short bed tank as 31 gallons, what you/we don't know is how far off the bottom of the tank the fuel pick up tube sits so that it does not pick up junk that accumulates in the bottom of the tank...

 

[CamperMike]

I have managed to get my 1500 with a 26 gallon tank down to having only 1 gallon left when towing my rv... but it was a nerve racking experience. I thought there would be another station sooner but didn't account for the fact I was in the mountains. It had said I had no miles left for a few miles.

 

[62Blazer]

I've been tempted to throw a 5 gallon can of gas in the bed and just drive until it ran out to know how far it would go. Shortly after I got my '16 with the 6.4L I was towing a trailer and got in a situation where the gauge was at zero and it had already stopped giving me a "miles remaining" or whatever message and just said low fuel. Was pretty nervous until pulling into a gas station. It was one of those situations where I wasn't used to the truck and how predicting how quickly the fuel gauge went down, and then just being a long distance from a gas station. Most of the places I drive around regularly it's rare you go more than 10 miles between gas stations.

 

[joesstripclub]

Tried to stretch my fuel a bit on a Missouri to Colorado trip a few years ago so that I could get to the cheaper fuel station. Ran with 0 miles remaining for further than I should have. Had the bed loaded with patio furniture, so not very heavy. Ended up pumping 31+ gallons into the truck so I was pretty close to empty. I've never come within even 5 gallons of empty while towing though.

 

[GTyankee]

Fill a 1 gallon jug with a true measurement of 1 gallon of gas at Sun Up during the summer.

You will notice that the 1 gallon jug is not completely full
The reason is Gasoline expands with Heat

Check that same jug of gas at 3 PM, you will notice that the gas has risen in that jug, almost to the point of over flowing.

The same thing happens with your soda bottles, when you buy them, the liquid is not all of the way to the top, they leave room for expansion & air pressure.

If you were able to completely fill a rectangular metal or plastic container, when the liquid warms up, the container would change shape, at some heated point, it would look more like an egg, just before it would begin springing leaks

 

[62Blazer]

Fill a 1 gallon jug with a true measurement of 1 gallon of gas at Sun Up during the summer.

You will notice that the 1 gallon jug is not completely full
The reason is Gasoline expands with Heat

Check that same jug of gas at 3 PM, you will notice that the gas has risen in that jug, almost to the point of over flowing.

The same thing happens with your soda bottles, when you buy them, the liquid is not all of the way to the top, they leave room for expansion & air pressure.

If you were able to completely fill a rectangular metal or plastic container, when the liquid warms up, the container would change shape, at some heated point, it would look more like an egg, just before it would begin springing leaks

Gas does expand and contract with temperature, just like anything else. The standard expansion rate is 0.069% for degree F. Basically if you put 1 gallon of gas in a can in the morning when it was 30 F and then it warmed up to 70 F that afternoon (which is a pretty big temperature change) you would now have 1.0276 gallons (about 3.5 ounces)....again, it does expand but lets also not get too carried away with how much. Usually the reason gas will spill out is from the built up pressure in a sealed container and not as much just from the increased volume.

 

[06 Dodge]

Just did a short trip to central WA an was able to buy diesel for $3.52 gallon in Toppenish, up in Yakima the lowest I saw it was $4.59 to as high as $5.19 ouch...

 

[jejb]

Had the Low Fuel warning message flash up on the dash yesterday, while I was headed in to town to fill up. Gauge still showed 1/8th of a tank, which is lower than I usually take it. Only took 25 gallons though. Disappointing that the fuel gauge is not more accurate.

 

[KoboldTaco]

Just did a short trip to central WA an was able to buy diesel for $3.52 gallon in Toppenish, up in Yakima the lowest I saw it was $4.59 to as high as $5.19 ouch...

Just saw my local chevron here in Cali take a dive down .30 more cents to 4.49. With their app discount, I’m able to shave another .25/.50/1.00 up to 25 gallons. Points add up quickly too and you can pay on your infotainment with car play.

Spent some time myself in Ellensburg from 94 to 98. Miss that region a lot. My Springer Spaniel is from. Brewster,WA too