Supposed to have a 26gallon tank, yet every time I fill up when I am right at red, I can only fill to 19 gallons.. what gives? Is the extra 6 AFTER red?

I was on the road yesterday all day, each line signifies 2.5gallons per my fill up and where it sat after filling up. Verified by putting $20.00 in and later $10.00 in and seeing where I was to where it filled up.

My question is where are my extra gallons??

 

[QUOTE=Black02CrCb;3284513] Is the extra 6 AFTER red?
[/QUOTEs
some of that volume is.


tanks are made to only hold 90% of their capacity. some headspace is needed for fuel expansion, pressure equalization and to keep the evap system from getting filled with raw fuel.


another possibility is the fuel sending unit is inaccurate. the only way to tell would be to run the tank completely empty and then fill it.


I would not worry about it.

 

It sounds like your fuel gauge is off a little.

 

First off I've never heard such crap that tanks are designed to hold 90% of their rated capacity, their rated capacity IS THEIR CAPACITY, fuel expansion & contraction is already factored in, not to mention a plastic tank will expand and contract depending on its load, which is why they look like muffin top pants on a chubby person over time.


Secondly, unless you run the truck dry (motor literally shuts down because no fuel) you're not going to see the end of the tank putting fuel in at quarter tank or a few notches under. The most I've fit into my truck is 22 1/2 gallons at 10 miles left on the console counter, but I've never run it out of fuel. Now most manufacturers will have the gauge read empty and still have a few gallons left as a reserve so you can get to a gas station.


Average tank on most any vehicle will give you 40-50 miles of leeway to get to a gas station (depending on how you drive it could be less) so with that said, assuming a Hemi truck on the highway with average load (driver and near empty cargo) and a perfect 17mpg at 65-70mph on the highway you easily gain back your missing 3-4 gallons of gas until empty past where the gauge reads and can cover 55-68 miles worth of room to find a gas station.


Our tanks are indeed 26 gallon tanks and DO indeed hold 26 gallons of fuel.

 

http://www.eco-fuel.com/service/tank...-and-diameter/


google fuel tank headspace and open pretty much any link....here's one from a 2 second search.

How much will may tank actually hold? Your tank, when full, will actually contain less fuel than it’s full capacity. For example, in a 275 gallon tank, the actual “usable” capacity is about 250 -256 gallons. The difference is the “head space” that is designed into the tank to allow for fuel expansion and for safe filling at the time of delivery.

 

Ok first off, there is a big difference between a car gas tank and an underground gas station fuel tank. First difference, the underground fuel tank sits in a static location that cannot dissipate cold nor heat very quickly as the ground insulates it quite well. Vehicle tanks on the other hand are essentially insulated by air and are some are even vented to compensate for vapor expansion, plus the fact its vented as you fill your tank (because your cap is off during filling!). I know in the pic a tanker truck is pictured, but there is a marketing bait & switch going on. Most vehicle owners only want to know what they can fill their tank up to safely, the guess work & math & safety is all accounted for, in commercial tankers they are regulated because of the space allotted for expansion as trucking companies may try to skim on loads to carry more not to mention they are carrying a lot more fuel than just 2 dozen gallons... regulations in a commercial setting are much different in the private sector hence the different way of rating.


Also as I stated before, vehicle tanks are rated for their capacity at a year round average of 60-80 degree air temp sweep not their internal volume, the anticipated expansion is built into the tank which is why when you fill your tank up at the pump the pump knows when to shut itself off before overflowing because of the filler neck design that prevents overfilling & thus triggering the pump shut off.


All you have to do to confirm what I'm saying is run your truck dry and be near a gas station and do a complete fill up. You'll see nearly 26 gallons on that 26 gallon tank, because 26 is the average at a given temperature it will be full to. In essence we're both right, but I had already said the expansion is already figured into the tanks construction, and 26 gallons is the max our trucks will hold at a steady average yearly temp.

From your website:

"The difference is the “head space” that is designed into the tank to allow for fuel expansion and for safe filling at the time of delivery."

They are referring to tank volume not its actual capacity.

 

great backpedalling.
right out of automotive technology, a systems approach by jack erjavec 4th edition page 693
"fuel height controls allow for only 90% of the tank to be filled. The remaining 10% is for expansion during hot weather".


Suggesting the tank has a "to contain" capacity rating is much more diplomatic than "I have never heard of such crap". Maybe try that first next time.

 

I'm thinking calibration issue. I'd run it down to red and drain the remainder into a 5 gallon gas can to find out. My old '02 Durango would and current '05 Ram does fill to the spec.
On both I've run the DTE to under 10 miles and filled up. That 32 tank on the Ram is a lot easier to fill so far this year as compared to last year, Lol.

 

As per the factory manual, approximately 6 gallons is the reserve. So unless you've run it past empty for a while, even right at 'E' at the dinging gas pump light you still have about 6 gallons.

 

Okay that is exactly what I thought, that it was past the red line and "0" marker. I guess I could have a gas can ready and try to run it totally dry.. although not sure that is good on the gas pump..