2011 Discovery 42A Fuel Tank Quantity Discrepancy

[RVPilot767]

Hello,

2nd owner of the MH (purchased in 2017). According to all promotional data, MH has 150 gal diesel fuel tank. After driving it over 20,000 miles, I am convinced it is only a 100 gal tank. The fuel gauge will react to low fuel based on distance travelled if starting with 100 gallons vice 150. I have contacted Spartan, they insist 150 gal tank is installed. To test my hypothesis, I once ran several miles (~60) with low fuel light on. It took almost 99 gallons to fill. That's the most I have ever been able to fill it. Has anyone experienced this? I guess the next step is for someone to physically check the gas tank to see if it is labeled for 100 or 150 gallons. The computer acts as if it is 150 gallons for range computations (~1,000 miles when full) but I have to use 500 miles for maximum distance between fillups. Not a big deal, but curious if this was even an option when built. Thanks!

[Fiesta48]

If you can only get 99 gal in then it's a 100 tank to you.
Do you want to push it, litterly, to find out if it's more?

[ga traveler]

Of all the things about camping I love, Refueling is NOT one of them. I put it off as long as I can. If I were you, I would want to make sure of the tank capacity. For a few dollars you can buy a LP gas tank quantity tape. These are made to install on the outside of the LP tank. You simply tape them on and pour hot water on the tape. The LP is colder than the air inside the tank and will show the fluid level of the tank. It should do the same with diesel. Drive it till empty and then check to see how full the tank is. If you drove the motorhome and put in 99 gallons of fuel, I believe you have the 150 gallon tank. I dont think you can pull that much fuel from a 100 gallon tank.