RDS auxiliary tank

I use my 90 gallon RDS as a transfer tank because I fuel up other equipment with it besides the F250. Another advantage is that I have a fuel meter on the filler hose, thus allowing me to keep track of how much fuel each piece of equipment is using, including the MPGs of my truck. I also have two filters on the fuel pump for fuel coming out of the tank: a 30 mic water separator and a 10 mic sediment filter.

Miles Away wrote:
To clear it you will have to stop and turn the ignition off.

On my 2016, you have to use some diesel so the sender can reset itself.

Dirt and water seem to be more prevalent in auxiliary fuel tanks, so for that reason I installed at fuel and water separator combination between the two tanks. Because of the added resistance, I also added at small low pressure (Mr. Gasket) fuel pump. Changing the OEM filter is always an option, but a real pain in the butt on Chevy's and GMC's, so I wouldn't want to do it more often than necessary. I run until my fuel gauge gets down to 1/4 tank and I switch on the pump. When the gauge shows full, I shut it off until I'm down to a 1/4 tank again, then repeat the process. With regard to your concerns about the fuel gauge. With the OEM tank constantly refilling on a gravity flow system, the OEM computer on GM vehicles will sense a fault when the fuel level shows full all the time, causing the gauge to zero out. To clear it you will have to stop and turn the ignition off.

austingta wrote:

dennych1 wrote:
I am looking to install a 60 gallon RDS gravity tank in back of my 2015 chevy 3500HD dually. Looking for some answers before purchasing.

1) can you fill your main tank as you drive
2) will it stop filling when main tank full automatically
3) does truck have a problem when fuel gauge always reads full until RDS tank is empty.
4) Do I add a fuel filter and water seperator(any suggestions.)

Thanks for the help
DEnnis

My results are a little different.

My 12VDC normally closed isolation valve seems to have malfunctioned and now it lets diesel flow into the main tank until it's overfull without power to it or the small fuel pump I have installed. I can see diesel in the filler neck. Nothing actually overflows or leaks out, so that's a plus.

However, my chech engine light is on and my fuel gauge and all DTE calculations are at LOW and low fuel lights are on.

It is clearly caused by this overfill situation. I have now turned off the manual ball valve at the tank and will report back after I burn some fuel. Hopefully, it will reset itself.

Anyone else have problems after staying full too long?

After driving around 30 miles with the shutoff valve closed, the system reset itself and all is normal now. As was reported in the 2010 thread on another forum I referenced, some of these trucks can't be left to fill all the way to the brim without some consequences. I need to find a solenoid valve that stays tightly closed when not powered. The problem is the diaphragm needs some pressure on it to close. I'll keep looking.

No harm done.

In case I run into an injector issue and Ford claims water in fuel possibly caused by moisture in the auxillary tank, I can show PM-22 at every fill up and my tank was installed by my authorized Ford dealer.

Grit dog wrote:

lawnspecialties wrote:
Good to know in case anyone is considering.

I had my RDS tank installed by my Ford dealer. The only other thing I do since I have this tank is I always use the PM-22. 35 gallons in the OEM tank plus just under 90 gallons in the RDS gets me close enough to 125 gallons that one 20 oz. bottle covers everything.

Had to google pm-22. Why would using an audio tank require you to use a cetane booster?

I also run Ford's PM-22. It has nothing to do with having an aux tank. I add it mostly because it adds lubricity to this ULSD fuel we are running now. The HPFP pump is lubricated only by fuel, so I'm adding a little insurance. I can buy a case for about $8-9/bottle and each bottle treats 125 gallons.

lawnspecialties wrote:
Good to know in case anyone is considering.

I had my RDS tank installed by my Ford dealer. The only other thing I do since I have this tank is I always use the PM-22. 35 gallons in the OEM tank plus just under 90 gallons in the RDS gets me close enough to 125 gallons that one 20 oz. bottle covers everything.

Had to google pm-22. Why would using an audio tank require you to use a cetane booster?

Doss wrote:
Do you guys ever wish you could pop the tank out to use all of your bed's capacity? That is making me lean toward a tank with a transfer pump.

By the time you bolt down and wire up a slip tank, it will be difficult to remove as well.
As said, you can get up to 80-90gal upright skinny tank that is just over 1' deep front to back. Once mounted you will have the better part of 7' left in the bed.

Fwiw I've had both RDS and JME tanks and both are top quality.

austingta wrote:

dennych1 wrote:
I am looking to install a 60 gallon RDS gravity tank in back of my 2015 chevy 3500HD dually. Looking for some answers before purchasing.

1) can you fill your main tank as you drive
2) will it stop filling when main tank full automatically
3) does truck have a problem when fuel gauge always reads full until RDS tank is empty.
4) Do I add a fuel filter and water seperator(any suggestions.)

Thanks for the help
DEnnis

My results are a little different.

My 12VDC normally closed isolation valve seems to have malfunctioned and now it lets diesel flow into the main tank until it's overfull without power to it or the small fuel pump I have installed. I can see diesel in the filler neck. Nothing actually overflows or leaks out, so that's a plus.

However, my chech engine light is on and my fuel gauge and all DTE calculations are at LOW and low fuel lights are on.

It is clearly caused by this overfill situation. I have now turned off the manual ball valve at the tank and will report back after I burn some fuel. Hopefully, it will reset itself.

Anyone else have problems after staying full too long?

There is no electrical connection if you use the RDS gravity flow install kit. My gravity flow RDS tank has worked perfectly since new. There is a check valve at the intersection where the aux tank line meets the OEM fuel line. The check valve closes when it senses the OEM tank is full and fuel has backed up the OEM line and contacts the valve. Simple is good.

I do not usually run with my aux tank open. I like to just refill the main when it gets down to about 1/4 tank, if I still have more driving to do that day.

Good to know in case anyone is considering.

I had my RDS tank installed by my Ford dealer. The only other thing I do since I have this tank is I always use the PM-22. 35 gallons in the OEM tank plus just under 90 gallons in the RDS gets me close enough to 125 gallons that one 20 oz. bottle covers everything.