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Our_Place
Explorer
Dec 02, 2014

Aux diesel tank in bed question...

I purchased a 2008 Silverado and it already had a 74 gallon aux tank in the bed hooked up to the fill pipe of the main tank. I sold the 74 gallon tank and purchased a smaller 37 gallon but was told not to hook it to the main tank, but not given a reason why? The previous owner had the valve open all the time and told me not to remove the main tank fill cap but just to fill the bed tank because they are connected, is that ok??

22 Replies

  • Sounds like he relied on the seal on the gas cap to prevent the fuel from coming out. They used to install valves on floor board for changing over the tanks. Now they put fuel pumps in gas tanks. I would be thinking of disconnecting that pump and installing an eletric fuel pump in the engine compartment and a floor board valve to switch between tanks.. During smog test think it would have to be on main tank to pass. Years ago any welder would weld up a tank before strict smog tests.
  • So if someone removes the normal filler cap then the fuel from the second tank would gush out it I suppose.
    That was simple but cheasy way to plumb it IMO.