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freddmc's avatar
freddmc
Explorer
May 04, 2015

Installing Aux Fuel tank in Bed of Ram 3500 Dually.

I am installing an 85 gallon aux fuel tank in the bed of my 2005 Ram 3500 dually. It will feed thru a 1/2 hose with an inline filter to the fill tube of the stock fuel tank via a manual shutoff valve. The aux tank will be vented via a rollover valve. However in looking at the stock filler setup I noticed that the vent for the main tank terminates near the top of the filler tube. If this is the case how will the main tank vent if the gas cap is still on. Is the cap vented or do I need to take it off while filling or??

Any help would be appreciated.

Thanks

Fred.
Tow Vehicles
  • Bionic_Man's avatar
    Bionic_Man
    Explorer
    May 05, 2015
    retispcsi wrote:
    I have a 60 gal RDS gravity feed. Mine has a vent tube on top of the tank. I ran a section of fuel line from the vent to the under side of my truck. It is bent much like a P-trap thus allowing air in and not anything else. However you do it your tank needs to be vented to work correctly.


    This is how mine is set up as well. Works great!
  • boogie_4wheel's avatar
    boogie_4wheel
    Explorer
    May 04, 2015
    The factory fuel tank is vented separately from the hose you are seeing on the filler neck. There is a vent to atmosphere located on the top of the tank. You can plumb in to the filler neck on the backside of the filler door for your aux.
  • retispcsi's avatar
    retispcsi
    Explorer
    May 04, 2015
    I have a 60 gal RDS gravity feed. Mine has a vent tube on top of the tank. I ran a section of fuel line from the vent to the under side of my truck. It is bent much like a P-trap thus allowing air in and not anything else. However you do it your tank needs to be vented to work correctly.

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