Diesel Doc

If you must do gravity feed at least put a valve at the bottom of the aux tank just in case for some reason your main system pops a leak of some sort or you are involved in an accident you don't end up dumping 100 gallons of diesel into the street.

2500

planning on carrying WMO... so prefer manually pumping oil into tank.

Flopster843

I have this same setup on my broken turd of a truck and have had it there for several years. It's about the only thing that hasn't broken. It has a ball valve in the bottom of a 93 gallon tank in the bed, goes in to a filter/water sep, then in to the float valve in the filler neck. I just open the valve before I make a trip and let it gravity feed the entire way, then close it when I'm where ever I want to be. It has never leaked and never over flowed. I'm going to transfer it over to whatever truck I buy when I get back. And in case you're wondering what will replace it, I am on DTR...

FiverBob

Here is a link with pictures on my installation. Since I wrote that, Northern Tools now has an installation kit from RDS that makes installation a piece of cake. They also carry the RDS tank which is a very good quality tank. I highly recommend Lightman's addition of the ball valve. I did not use the main tank vent line for feeding which technically changes the dynamics of the factory installation which I hear is a no no in some states. The insertion of fuel in the filler pipe pretty well follows the intent of that part. I did not add the filter since I am going into the main tank anyway which is filtered, but that is probably a good idea. Be sure you put a locking cap on that aux tank - - makes it too easy for someone to grab a bunch of your money real quick. I did rinse the tank out with some diesel before installing "just in case". (it was clean!!) The RDS tank does have a gauge inside the tank, but I also just watch the dash gauge - - when it starts to move I know the aux tank is empty.

I have had my tank in now for 5 years - - I love it. I turn it on while on the road and run on it. I turn it off otherwise. It does not matter if it is a bit slow - - I certainly don't sit there and watch it. Sometimes I will let the main run down to about 1/4, then turn it on. Now wires, no pumps, no valves. I have had pumps and valves fail me and ended up stranded in the desert in my motorhome - - no thanks. I am not so lazy I cannot reach over the bed and turn a valve - - called the KISS principle.

https://www.dieseltruckresource.com/...n&onlynewfaq=1

Bob

roughstock

I run a gravity feed aux tank on my truck. I went to Napa and got a fuel valve, like the one that you see on dual tank chevys. There is a one wire hook up. I toggled it in the cab. one side is plugged and when i flip the switch, it opens the valve to the aux tank to dump in to the main tank.

CrazyFloyd

I put one of those valves that are meant for your oil pan on the bottom of my aux tank. Still fighting the overflow problem.

FiverBob

Have you changed your gas cap to a locking cap? Could that cap be leaking? It is my understanding they are supposed to breathe in only and not allow fluid to come out. Mine never overflows and I have an 03 but with locking cap. It did not overflow with the stock cap either.

CrazyFloyd

It does not leak from the cap; it leaks from the stock tank itself (I think from the big plastic ring on top of the tank).

dezeldog

I read somewhere that there's another vent tube or something of that sort on top of the tank, within the plastic ring that has a cap on it. They say that possibly that cap is not diesel rated and has rotted out. Since I have the vent mod I used the old vent for the feed from the aux tank. I have had a grav. fed aux tank for about 2.5 yrs with no issues at all. Hope this helps.

Jim

haulin-rv

I have gravity fed on my last 5 trucks for a total of over 1,000,000 miles (no typo). Its 100% legal to gravity feed into the trucks tank. It will not overflow, as long as you do not tank the fuel cap off on the truck. I run a ball valve on my tank to turn off the flow if I want.

macattack_ga

law specifically says you can't gravity feed to carb (or injectors I think).
tank to tank or tank to lift pump is not mentioned in the law.