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gat75's avatar
gat75
Explorer
Sep 20, 2016

Question about RDS gravity feed Aux Tank

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??

16 Replies

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

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