Auxiliary fuel tanks

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Rob&Deryl

Rob&Deryl

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I am thinking that for long trips it may make sense to have an auxiliary fuel tank to extend our range. A tank that more or less doubles what the stock tank can do seems as if it might not occupy too much of the truck bed.

I would love the thoughts from those of you who have done this.

Best case would be a tank that could come out when the 5th wheel isn?t going to be used for a while.

Thanks
 
Watching this thread, pretty sure I'd like to do the same.

Two acquaintances have auxiliary tanks in their Ram pickups.  They're plumbed right into the fill pipe and work via gravity so no pump needed.  Can't do that with GM products, it confuses the computer.

Keep an eye on dimensions: a hard tonneau cover will limit how tall the auxiliary tank can be.
 
I too have a Cummins pulling a fiver, I really see no need for extra tank(s) as I can run all day on one fillup if necessary as long as I keep my fat foot out of it. Besides, I need get out and stretch with a coffee time, 12-14 hour days behind the wheel are long behind me.
 
I have had three vehicles with auxiliary fuel tanks.

They do give you a feeling of comfort regarding running out of fuel.

My latest one is on my Jeep Commander.  I carry 55 gallons.

Mine is for long expedition trail rides.

I am the mobile gas station for my buddies.  Of course the gas is $20 a gallon way out at the end of the trail.

Maybe even $30 if you are really far off the trail, but then you start losing buddies.
 

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A key phrase in your question was " a tank that could come out when the 5th wheel isn?t going to be used for a while."  The tank and even 50 gal of fuel can add over 400#, and lower payload by that amount.  For some, that would run a SRW truck over weight when towing a FW.  Taking the tank out cures the problem.
 
Have you ever considered a DIRECT REPLACEMENT tank? They remove your stock tank and bolt the replacement tank in its place! No extra fuel lines, no extra valves, only one fill location your fuel level gage works etc. Doesn?t reduce the bed space. Aero tanks in San Bernardino, CA and Transfer Flow both make them and probably the are others.

They will almost double your fuel capacity (depending on the truck brand/LB/SB etc) I had Aero Tanks install their 60gal replacement tank in both my ?98 and ?07 Ram Cummins.

Now, will you ever re-capture the cost of the tank? You can rough in some numbers to get an idea. Re-capture or not when traveling xcountry it is sure nice to by-pass the expensive fuel states/cities.

BTW- I think that DOT considers it illegal to plumb an aux tank into the stock tank fill lines. If so I am sure that in case of an accident your insurance Co. would frown on it. Just something to look into.
 
I am on the fence on installing an auxiliary fuel tank because we are planning a trip to Alaska in 2020, where as I understand there can be long distances between fuel stops in some areas.  Secondly and for the longer term, having an auxiliary tank would enable us to buy extra fuel at lower prices before travel into higher price fuel markets.
 
There are long distances between stops but nothing that the stock tank won't handle with proper planning. Once you leave the lower 48 fuel is darned expensive wherever you go and it gets worse as you travel north. A fill up in Whitehorse will have your cc running for cover.
 
We went with switching out the stock tank for a larger tank rather than adding an auxiliary tank. That larger tank sure came in handy traveling thru Canada and Alaska this summer. Especially Canada where fuel prices varied widely from place to place. With a hard tonneau cover, we wanted to keep the space for the toolbox and other things.

Vicki
 
I would expect that a long bed truck has more room underneath than a standard bed so a larger tank could fit.

Is there room for a larger tank on a standard bed 3500?

Since on some models, there are factory optional larger tanks too, the factory must be able to calibrate the fuel range guesser to various tank sizes.

If you install a larger after market tank, can the the new tank size be programmed in? By the dealer or tank installer?

Aside from the tank makers listed above, who else makes em?

Thanks
 
I installed 50 gallon Titan in bed auxiliary tank for a few reasons.  First I have a long bed dually so space and weight are not a concern.  Second the Titan replacement tank would gain 24 gallons for $1500.  The 50 gallon auxiliary was $1100.  Third I feel gravity fill auxiliary tanks are a fuel spill waiting to happen.  Titan comes with an electric fuel pump, filter, and control module. 

My main reason for wanting extra capacity was to be able to get anywhere I'm going without having to get fuel wile hooked to my camper. 
 
Concerning the Replacement Fuel Tank level sender issue. Yes the replacement fuel tank is a few inches deeper (Aero has a skid plate available, I didn?t require it)

I am going on memory now, (from 2007-2008) Aero Tanks uses your original fuel pick up, then ADDS extensions to its OA length which lowers the pick up down to the bottom of the replacement tank. This means that you will go a couple hundred miles (depending on load) on a a full tank before the gage even comes off of the FULL mark, that?s OK by me, it?s near the ?E? mark that I am interested in! What the other replacement tank manufacturers do, I don?t know. I had Aero install their tanks in their CA shop in my 2 previous trucks.

For the capacity of a replacement tank for YOUR truck you will have to call the manufacturer with the specifics of your truck for what size they have available.
 
I have a DeeZee combo fuel/tool box.  Holds 46 gallons (164L) and it is plumbed into the fill line of my 2017 3500 GMC.  I don't have any issues with the fuel gauge - I have heard that you need to let your fuel level drop so the truck doesn't see it sitting at full for too long. I usually let it run down to 1/2 then turn on my 30 GPH pump (which is also connected to a normally closed solenoid).  When the gauge reads about 3/4 I shut it off and the gauge tend so to keep rising to about 7/8 full.
 

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I installed this tank a while back & just love having the extra fuel on board; makes the box a bit smaller but it is nice only having to fill up once a month!

Haven't pulled the RV since installing it, but it is ready to go when we do!

I have a switch on the dash with an indicator light to show me when the solenoid is open & fuel is flowing, filling the truck tank.
 

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Nice tank Metalman.  From the photos it looks like you have run the fuel and vent lines through the box without grommets or bulkhead connector.  Over time you may wear a hole in the line. 
 
1blue78 said:
Nice tank Metalman.  From the photos it looks like you have run the fuel and vent lines through the box without grommets or bulkhead connector.  Over time you may wear a hole in the line.
Click to expand...

I suppose that may be possible.  At least with the "in-line" solenoid it is isolated when the switch is in the off position.  Not a bad idea though.
 
Like some of you I wanted more range.  But I also wanted a lot of storage in the bed which all the combo tanks I could find did not have.  Ended up installing this setup.


I set it up with the fill on the right and the pump on the left.  The trunk tank filler is on the left.  Most trips I get home and refill the trunk from the bed tank and then go and fill the bed tank.  I've even been filling the bed tank at the station while at the same time pumping from the bed tank to the truck tank.  Odd I know.  But end of the day, it works well for me.


-Chak


PS: I can't wait for the day where forums manage picture sizes for you.  Highly discouraging to post pics (which most would say are helpful) when you have to spend 5-10 minutes getting it to a format they will accept.  And every forum is different.  One more reason Facebook in winning.
 

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Chakara said:
Like some of you I wanted more range.  But I also wanted a lot of storage in the bed which all the combo tanks I could find did not have.  Ended up installing this setup.


I set it up with the fill on the right and the pump on the left.  The trunk tank filler is on the left.  Most trips I get home and refill the trunk from the bed tank and then go and fill the bed tank.  I've even been filling the bed tank at the station while at the same time pumping from the bed tank to the truck tank.  Odd I know.  But end of the day, it works well for me.


-Chak


PS: I can't wait for the day where forums manage picture sizes for you.  Highly discouraging to post pics (which most would say are helpful) when you have to spend 5-10 minutes getting it to a format they will accept.  And every forum is different.  One more reason Facebook in winning.
Click to expand...
It should not be taking more than one minute to resize a photo. Open it up in any photo editor and change the horizontal dimension to 1000 px, click resize and then save with a new file name. Works every time.
 
The first year we were full time in our fiver our small tank on our F350 made some planning interesting out west.  We never had any issues but I found I had to run my tank lower than I wanted to.  Started looking at options.  Didn't want to spend a ton of money.  Didn't want to consistently haul an extra 150 to 250 pounds of weight when not needed.  Plus I didn't want to give up any more room in my PU bed than I had to.

Ended up using four 5-gallon diesel cans with easy-pour spouts.  They fit nicely in my tool box and I only filled them when I knew the extra capacity was going to be needed.
 
I have a 105 gallon auxiliary tank in my truck. It makes a world of difference not only in range, but I can now take my time when shopping for diesel so that I can get the best price. For every penny cheaper I can find fuel, I save $1.00 on the total fill up. It really pays to search for the cheapest fuel. When we go to the beaches in California, I can top up everything and not have to pay the state's huge fuel prices.

When towing, my truck gets about 8 mpg leaving me with about 220 miles of usable range. With the auxiliary tank, I can push it to the limit, pull over to transfer fuel and stretch legs, then get back on the road. Over a day of driving, this can save me 20-30 minutes.
 
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