Hello to All,1st, thanks in advance for taking time to read my post. I have a 51 gallon RDS alum tank that I purchased new from NTool about 10 years ago. Used it regularly while traveling with my 2009 D/A 2500. However, have not been on any long trips in couple of years, therefore have not needed the extra capacity. This past weekend, had to make 2 trips out of town, so I added 30 gallons to aux tank to save from making an extra fuel stop.Later into the trip, I Got concerned about using the diesel from the tank, was wondering if tank might have had condensate in bottom of tank.I know that the factory GM filter is supposed to catch any water coming to engine, still, just didn't want to chance ruining an injector. I also cannot find any drain plugs on the bottom of tank for test draining.So, to this point, I have not allowed any fuel to drain out of aux tank. I got 30 galls of diesel sloshing around, just begging to be consumed, ha, ha.Are my fears groundless??

I'd add some Diesel 911 to it and not worry about it otherwise.

If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.

Specularius wrote:If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.Good post.

I have the same tank and always use a fuel conditioner which is supposed to take care of water. Never had a problem (knock on wood)That stuff is supposed to help clean injectors and add lubicity too so I feel it's a small price to pay to avoid trouble

mpierce wrote:Specularius wrote:If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.Good post.Ditto on good post, Thanks to everyone for your input!

Question about RDS gravity feed Aux Tank | Good Sam Community

n0arp
Explorer
Sep 20, 2016
I'd add some Diesel 911 to it and not worry about it otherwise.
Specularius
Explorer
Sep 20, 2016
If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.
mpierce
Explorer
Sep 20, 2016
Specularius wrote:
If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.

Good post.
aruba5er
Explorer
Sep 20, 2016
I have the same tank and always use a fuel conditioner which is supposed to take care of water. Never had a problem (knock on wood)
That stuff is supposed to help clean injectors and add lubicity too so I feel it's a small price to pay to avoid trouble
gat75
Explorer
Sep 20, 2016
mpierce wrote:
Specularius wrote:
If you are really worried, then park on a slope so that the fuel outlet is on the low side. Wait a couple of hours. Disconnect the hose from the fuel fill tube and place in a jug. Then open the valve and drain some out and inspect.If there is any moisture present, it will drain out first.

Good post.

Ditto on good post, Thanks to everyone for your input!
dave17352
Explorer
Sep 20, 2016
I once read up on this condensation thing and unless you left the cap off really the only condensation you would get is from the volume of air in the tank once. That would not amount to really anything. I too have a 50 gallon aux tank I haven't used in about three years. I don't think I would be concerned, but I too always use a additive which is suppose to help solve water problems.
GoPackGo
Explorer
Sep 20, 2016
dave17352 wrote:
I once read up on this condensation thing and unless you left the cap off really the only condensation you would get is from the volume of air in the tank once. That would not amount to really anything. I too have a 50 gallon aux tank I haven't used in about three years. I don't think I would be concerned, but I too always use a additive which is suppose to help solve water problems.

I also have an RDS tank. These things all have a vent so there is a constant direct connection to outside air. All tanks will have some kind of vent system.

I agree with the person who said to sit your truck at an angle, then disconnect the line where it meets the OEM truck line and drain a little fuel out. Either that or just start running it and drain your fuel filter every day for a while.
Dave_H_M
Explorer II
Sep 21, 2016
I disagree with the vent circulating new air into the tank to any minutia of a degree that it would even be measurable.

I ran an RDS 70 gal aux for 13 years and did not keep it filled during the off season. Nary a problem with water even without additives.
MEXICOWANDERER
Explorer
Sep 21, 2016
Grab broom stick

Select major independent gas station like a Union 76 without mini store

Park

Ask for owner or manager

Beg him to put 3" worth of water detector paste on tip of broom stick

Stick broom stick into tank

If tip comes up red, then put your worries to work. If stick comes up colorless put worries to bed.

Every gas station has this paste. But the more the gas station looks like a 7-11 the less interest you will find in your project.
n0arp
Explorer
Sep 21, 2016
MEXICOWANDERER wrote:
Grab broom stick

Select major independent gas station like a Union 76 without mini store

Park

Ask for owner or manager

Beg him to put 3" worth of water detector paste on tip of broom stick

Stick broom stick into tank

If tip comes up red, then put your worries to work. If stick comes up colorless put worries to bed.

Every gas station has this paste. But the more the gas station looks like a 7-11 the less interest you will find in your project.

https://www.amazon.com/dp/B00207LS5M Might be nice to have on hand for $5...