Aux diesel tank in bed question...

[Our_Place]

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??

[hawkeye-08]

Regarding the pump attendant removing the fuel cap when you don't want it touched, just switch to locking cap and don't give them that key.

[Bird_Freak]

GoPackGo wrote:
I have an RDS tank. The RDS install kit INCLUDES a shut-off valve where it plumbs into the main (OEM) fuel filler line. When the fuel level backs up the OEM filler line and reaches the valve, it closes, stopping more fuel from flowing. This way it cannot get up to the level of the outside filler cap.

Northern Tools has the kit. $80.

Tim

I just installed one of these in my buddys new truck last weekend. Works really well.

[hitchup]

We've had the DIY RDS gravity fed in-bed tank. It did leak after awhile if DH left the valve open. But the Ford dealer fixed it for us.

Then we upgraded to the in-bed Transfer Flow fuel pump version with a professional installation. DH switched his tonneau covers a few times until he could find the right one to fit over the tank.

Finally, we upgraded the truck and had Ford install the under-bed Titan replacement tank. It's been the best and easier. Just one fill-up, instead of two.

Still feel Ford needs to go back to dual tank option. Then you can fill on either side of Truck.

[wlstroud]

My RDS aux tank has a tank shut off and a float check valve in the tee on the filler pipe. The check keeps filler pipe from filling up to the truck fuel cap. The only problem I've had in 8 years of aux tank use is I can't leave the tank "on" all the time as that throws an engine code when the computer doesn't see the main tank fuel level decreasing while driving. I have a 99 gal tank/toolbox. It's been great for range increase and for fuel price shopping.

[wlstroud]

My RDS aux tank has a tank shut off and a float check valve in the tee on the filler pipe. The check keeps filler pipe from filling up to the truck fuel cap. The only problem I've had in 8 years of aux tank use is I can't leave the tank "on" all the time as that throws an engine code when the computer doesn't see the main tank fuel level decreasing while driving. I have a 99 gal tank/toolbox. It's been great for range increase and for fuel price shopping.

[Our_Place]

Ok let me clear some things up, first I don't have the gasser anymore that was in my signature (signature corrected) and the aux tank does have a manual valve for shutting it off. I have not tried to remove the "T" that is installed in the main tank filler hose but there could be some kind of "float shutoff" in there, it's too big to just be a place to connect a 3/8 line to. From my understanding the original owner has had the truck that way since new, 2008??

[GoPackGo]

I have an RDS tank. The RDS install kit INCLUDES a shut-off valve where it plumbs into the main (OEM) fuel filler line. When the fuel level backs up the OEM filler line and reaches the valve, it closes, stopping more fuel from flowing. This way it cannot get up to the level of the outside filler cap.

Northern Tools has the kit. $80.

Tim

[Nutinelse2do]

We have a valve on ours we turn for gravity feed when our low fuel light comes on.
It's nice having the option of getting fuel where we want, when we want, usually without the fiver in tow. Much easier that way, and can get into the smaller stations that are sometimes less expensive.
DH set it up that way to not mess with the truck computer gas thingee.
Sorry, don't know what it's called 😮
Cheryl
We have 45 gal RDS aux tank

[mich800]

dave17352 wrote:

mich800 wrote:

fj12ryder wrote:
Okay, now you got me curious.

Why doesn't the auxiliary tank drain into the main truck tank until the auxiliary tank is empty, when the valve is open? Seems like it would if the auxiliary tank is higher than the regular tank.

What am I missing? Surely it isn't just the seal of the fuel cap?

That is how it works. You can get a tee that fits in the filler neck that has a shut off float in it. If someone just connected to the filler neck without some sort of shut off it would flow to the cap.

Yes some people leave the valve open and the cap should prevent any fuel from coming out. I choose to just open the valve when I run low on fuel. In fact with my 50 gallon tank when I open it, it drains far enough down that the level of the diesel is not higher than my filler cap. So it is really a no brainer. I have a 34 gallon tank.

I choose not to trust everything being spill proof around the cap because it is just so easy to flip the lever once. Literally about once every 800 miles or so. No big deal.

I do it similarly. I flip the valve if I am low with no stations in sight or if fuel prices are high. I typically top off my aux tank when I find a good deal and only use it when prices are rising. My own little futures market.

[dave17352]

mich800 wrote:

fj12ryder wrote:
Okay, now you got me curious.

Why doesn't the auxiliary tank drain into the main truck tank until the auxiliary tank is empty, when the valve is open? Seems like it would if the auxiliary tank is higher than the regular tank.

What am I missing? Surely it isn't just the seal of the fuel cap?

That is how it works. You can get a tee that fits in the filler neck that has a shut off float in it. If someone just connected to the filler neck without some sort of shut off it would flow to the cap.

Yes some people leave the valve open and the cap should prevent any fuel from coming out. I choose to just open the valve when I run low on fuel. In fact with my 50 gallon tank when I open it, it drains far enough down that the level of the diesel is not higher than my filler cap. So it is really a no brainer. I have a 34 gallon tank.

I choose not to trust everything being spill proof around the cap because it is just so easy to flip the lever once. Literally about once every 800 miles or so. No big deal.

[mich800]

fj12ryder wrote:
Okay, now you got me curious.

Why doesn't the auxiliary tank drain into the main truck tank until the auxiliary tank is empty, when the valve is open? Seems like it would if the auxiliary tank is higher than the regular tank.

What am I missing? Surely it isn't just the seal of the fuel cap?

That is how it works. You can get a tee that fits in the filler neck that has a shut off float in it. If someone just connected to the filler neck without some sort of shut off it would flow to the cap.

[fj12ryder]

Okay, now you got me curious.

Why doesn't the auxiliary tank drain into the main truck tank until the auxiliary tank is empty, when the valve is open? Seems like it would if the auxiliary tank is higher than the regular tank.

What am I missing? Surely it isn't just the seal of the fuel cap?

[azdryheat]

RDS successfully uses gravity fed in-bed fuel tanks. I have one in my truck and it gravity feeds just fine. Do the nay-sayers for gravity feed have any actual experience with the process?

[dave17352]

wanderingbob wrote:
I have plumbed the same way except I leave the valve closed , when the gauge on dash gets low I open the valve and let gravity fill the main tank , If I forget and leave it open , nuttin happens ! Of course me and mickey mouse have only been doing it for fourteen years with no mishaps . Myself I would be afraid of electric pumps and automatic******, manual works for me .

I did exactly the same with my 50 gallon tank, the second time I installed it on my 2011 silverado. Believe me moving that little lever on the valve is really, really easy and it works perfectly. The first time I installed a solenoid switch and a lighted rocker panel switch. It worked too but cost me about a hundred bucks to set up. I agree manual is the the way to go. Piece of cake.