Auxiliary tank - full or empty?

[Durb]

After a long trip, my auxiliary tank is currently empty. I have winterized my trailer and won't be towing until next Spring. I have no need for the added range the tank offers until then. Should I leave the auxiliary tank empty or fill it up for storage?

[hornet28]

What is the expected advantage of keeping the tank full?

You don't have the hassle of dealing with stations and it's customers. I haven't been in a station since 10/17 and still have over 30 gals in the tanks

[JRscooby]

memtb wrote:
Fill it.....treat it! The few extra pounds of fuel carried will be inconsequential to fuel mileage! If the difference is even measurable, it would be minimal..... a small headwind would affect mileage much more! memtb

Headwind every trip, that changes to tailwind every time you stop.
I have never liked to leave a load sit on a spring-ride truck.
Then there is the issue of the fuel itself. At this time of year, depending on where he is likely to buy fuel blended for winter. Warmer weather, when using the fuel, get less mileage.
What is the expected advantage of keeping the tank full?

[memtb]

Fill it.....treat it! The few extra pounds of fuel carried will be inconsequential to fuel mileage! If the difference is even measurable, it would be minimal..... a small headwind would affect mileage much more! memtb

[azdryheat]

If it's empty, it's empty. I wouldn't fill it and I don't with my tank.

[kellem]

Gas or Diesel, store with full tanks.

[JRscooby]

On my trucks, getting a tank completely MT could not happen. But the transfer tank, it was fairly easy. With a partly full tank, you get condensation on the sides, drains down thru fuel. You can have wet fuel issues when start using again. Or you can have water freeze in bottom of tank fittings, and leaks.
But if the tank is MT, just pull the plug to drain before use. Or leave drain open until ready to use.

[fj12ryder]

If the tank is full there is less room for condensation to form. I always fill both tanks before I put the Cummins away for the winter.

[Lantley]

My thought is keeping full. Avoid any moisture or condensation in the tank.
Weight and cost are negligible factors for me.

[Bionic_Man]

My aux tank stays full all the time. My truck is rarely used in the winter. Never had a problem with the fuel, and I don't use any additives.

[Edd505]

I keep mine full at all times, trucks filled from the tank and tanks gets filled at the pump, keeps the diesel fresh. I use the TSD fuel card currently at the T/A truck stop for best price. Closest is 75 miles from home in a city I get to once a week or maybe two at the most.

[Grit_dog]

It won't hurt to let it just sit full, but why...
Either leave it empty or empty-ish, or continue to use it if it's a gravity feed tank. Is it an actual auxillary tank, or a slip tank you have to pump in?

Unless the truck is just parked, then I'd leave it empty.
If it's parked outdoors, condensation is a concern. In doors, not hardly at all.

[Durb]

I'm not concerned with the weight or cost of the extra fuel. Do I have to put an anti-algae agent in the fuel if I let it sit for 6 months? If so, recommendation. The weather will be cool and humid (rain).

[wanderingbob]

Fill it up , helps prevent condensation , also fuel is pretty cheap now .

[JRscooby]

jdc1 wrote:
Diesel? Diesel will last a day before forever. Gas? Gotta keep cycling it.

This. But you also need to think about the extra fuel and wear needed for hauling the weight of fuel you don't need.

[jdc1]

Diesel? Diesel will last a day before forever. Gas? Gotta keep cycling it.