5 Gallon Diesel Fuel Can

[wjmst]

I have a yellow 5 gallon diesel fuel container that I filled up this morning. There is a safe fill mark on it and I filled the can to just below that mark. I look up at the gas pump and the meter reads 5.071 gallons! Wow! Did I just break some laws of physics?

So my question is:

Is a 5 gallon container really 5 gallons or was the pump meter off? Any way to test this?

Thanks

 

[dave1949]

That's less than a tenth of a gallon, maybe 1-1/2 cups. I wouldn't worry about it. I doubt the can/jug markings are that accurate.

 

[Furu]

Not sure how much below the mark "just below the mark" is as you define it.
5.071 gal is 5 gal and 9.08 oz. That is basically a cup. Did you get down level with the line, or look at an angle from above as you were pumping?
.071 gal would be 16.4 cu inches of fuel.
My 5 gal cans are 8.5 wide by 13 long thus with 231 cu inches per gallon the height difference of the depth of 16.4 cu inches (.071 gal) is only 0.148 inches (between 9/64 inch and 5/32 inch)
That is barely over 1/8 inch.
With the fuel sloshing you would have to wait for nearly a minute for all motion to subside before you could adequately see that difference. On top of that as soon as you pickup or set down the can (assuming it is plastic and to see through it it must have been) the deformation of the weight on the container sidewalls will change the height of the fuel due to sidewall deformation of the container.

Not defying physics just calculating math.

Oh by the way my cans full marks that are embossed on the plastic are slightly wider than 1/8 inch so that is the same introduced error that your 0.071 gal had in depth.

Testing is down by the state at cycles and is marked on each pump.
To test it your self get a measuring cup and have at it.

 

[square1]

5 gallons in a warm container is more than 5 gallons in a cold container if you go by the (not accurate to start with) mark on the can,

 

[George2615]

The fill mark on the container is just a reference point. The container will hold more than 5 gallons. Filling to the mark leaves room for expansion.

 

[bcp]

And if it was a rectangular plastic can, the sides are probably bowed out a bit, giving it more capacity.

Bruce

 

[charlz]

The can is not accurate. However, there is some seasonal variation brought on by temperature changes. Also pump to pump can vary, it is up to the gas station to make sure their pumps are calibrated and the State typically tests them once a year.

 

[bilrus61]

My old Chilton diesel can says 6 gallons on the side. Maybe yours is a 6 gallon one also?

 

[PMA]

I put 5 1/2 gallons in my five gallon cans all the time.

Sent from my iPhone using TractorByNet

 

[wjmst]

Thanks for all the replies. I guess I'll just put enough fuel in the can to reach the safe fuel mark and whatever amount it turns out to be, then that is what it is!