Question for those with an Auxiliary diesel fuel tank

[Bionic_Man]

So, for the 2nd time in 3 years, my in tank fuel pump on my RAM failed. Happened two weeks ago pulling my boat on a 500 mile trip to vacation. The good was it didn't leave us stranded, happened in probably the best possible place, and was able to limp into literally the last town with any mechanics for about 250 miles.

Dealer said that the fuel pumps are very reliable, and they don't know what is causing the problems.

On the way home, I ran the 60 gallon RDS tank dry, and looked into it before filling it today. There is definitely contamination in the tank. I am wondering if this is normal (since I can't see into my OEM tank, I really have no idea what is in there), or if this could be the root problem of my fuel pumps taking a dump?

The tank is plumbed into the filler tube, drops into the main fuel tank. I am wondering if I should put in some sort of fuel filter to go between the aux tank and the OEM fuel tank? If so, which would be the best way to do it?

FWIW, I almost always fill at the same station (which I will now change), and am good about changing my fuel filter every other oil change.

Thoughts?

[S_Davis]

I was worried about gravity flow through a water separator so I decided to just add a pump, it is on a 30 minute timer and will transfer about 18 gallons. The tank had condensation in it when I got it so I was more worried about moisture than debris.

[Beaker]

No large piece of crud seen.

[fj12ryder]

Beaker wrote:
My Transfer Flow has a filter between tank and fill tube.
Has plugged once in 14 years and the system alerted me to that fact.

Was the plug caused by a cumulative effect, or a one-time piece of crud?

[Beaker]

My Transfer Flow has a filter between tank and fill tube.
Has plugged once in 14 years and the system alerted me to that fact.

[fj12ryder]

Bionic Man wrote:
Just an update. I’ve added a inline fuel filter between the aux tank and the regular filler liner.

I also added a filter on the aux tank overflow tube since they are inexpensive and it seems like the contamination could possibly be coming from that?

The one issue I had is that the one time I left the manual valve open from the aux tank, it did over fill the main tank, probably lost a couple cups of fuel before I saw that. Any idea why that would happen?

Im still considering a spin on type fuel filter but not 100% convinced that it will work with a gravity feed.

These are the filters I’m using now. Filter

Fixed the link: Inline Fuel Filters.

I discovered our new-to-us truck already has the feed line hooked up for an auxiliary tank, which makes sense because I believe the guy used it for hotshotting. But the nice thing is he, or whoever, hooked up a nice lighted rocker switch on the dash that operates a solenoid valve for the auxiliary tank feed. So, if and when I get a tank I'll be set up ready to go. Just run the line to the valve, and BOOM done.

[Turtle_n_Peeps]

A spin on will work just fine on gravity feed. I have many tanks on my ranch with spin-ons.

[Bionic_Man]

Just an update. I’ve added a inline fuel filter between the aux tank and the regular filler liner.

I also added a filter on the aux tank overflow tube since they are inexpensive and it seems like the contamination could possibly be coming from that?

The one issue I had is that the one time I left the manual valve open from the aux tank, it did over fill the main tank, probably lost a couple cups of fuel before I saw that. Any idea why that would happen?

Im still considering a spin on type fuel filter but not 100% convinced that it will work with a gravity feed.

These are the filters I’m using now. Filter

[SDcampowneroper]

I have had, made my own in bed 55 to now 85 gal. in bed aux. tank since 1984. None have been plumbed into the truck Always used an GPI electric pump for transfer with a Goldenrod water separator filter.
Aux. tanks do have water condensation issues when they are not full. The water separator filter has saved us many a OEM fuel filter, and I just dry them out and reuse them.
Our reasoning for not plumbing the aux. into the main, is for filtration and in boondocking season and summer season to switch to gas from diesel to fill mowers gennys and such. The truck became a filling station. Gas cans a thing of the past. We buy fuel when and where we want, at the best price.

[Grit_dog]

fj12ryder wrote:
Thanks for the input, I wondered if those would work well enough, but I guess they do.

Of course.

They'll catch any large junk. And anything small enough to pass through a single paper filter will also pass through a fuel pump just fine.

Great chance it has nothing to do with the slip tank anyway. Doesn't compute unless somehow someone with a pristine truck who's pretty OCD about their vehicles (like Bionic is, based on his posts) would have more crud in the tank than most construction equipment.

[fj12ryder]

Thanks for the input, I wondered if those would work well enough, but I guess they do.

[Bionic_Man]

I went to a diesel performance shop today. They recommended a simple, 1/4" inline fuel filter between the aux tank and the OEM tank.

[fj12ryder]

Trackrig wrote:
...
If I had a bed tank that was plumbed in, I would have a filter on it.

Bill

What kind of filter? I've seen just small ones that would work with gravity flow system.

[Grit_dog]

Bionic, your fuel filters are downstream of the pump, so not catching anything from the slip tank before the pump.
Idk how much “contamination” you observed in your slip tank, but if you ever saw the bottom of many/most construction equipment and high mile trucks, you’d likely not have anything like that.
As someone who used to and still does fuel more stuff out of transfer tanks and slip tanks than most, I doubt it’s your slip tank.
Although to your point, you have very bad luck with the fuel pumps or another issue.
They are generally very reliable and long lasting on all post 2004 Dodges.

[Grit_dog]

JRscooby wrote:
OP, when you replaced the pump did you check the fuel in bottom of tank for trash?
Do they run a sock on pump intake?

For the people that carry spare fuel filters, how do you store it? How do you fill it if you have to change?
Early '90s 2 drivers and I fueled at same station went different jobs. When my truck showed symptoms, I pulled into another station, filled the filter from pump. Both drivers sucked fuel out of tank to fill their filters. Water past filter, 2 engines to overhaul.
Later, I looked at a filter that had rode in toolbox for awhile, too much dirt to use. Rest of the time I worked I carried filter in a piece of PCV pipe, with duct tape holding caps on. Also carried a jug of known clean fuel. Later I started to keep bottle of baby powder handy, quick way to clean spill off clothes.

Fill the filter with what?
Hasn’t been a light duty diesel truck made in the last 20+ years that requires manually filling the filter(s) to prime.