I tried the search....someone here posted the supplement that came with our trucks warning about aux tank installs. I have my owners original.....but need the link.

Thanks,

Shane

 

Here is the diesel suppliment, not sure if it's in there (not sure if this is what you are looking for).

In the fuel system diagnosis, aux tank is the number 1 culprit

 

I know I read somewhere that an aux tank is not recommended cause of the possibility of condensation which in turn will damage the fuel system.

Am I wrong?

Shane

 

I can't find much either.
Ford discusses this issue so one would think they allow it if they're offering troubleshooting tips?
Or does Ford offer a factory auxiliary tank?

If engine cranks but won’t start
Prolonged starter cranking (in excess of 10 seconds) could cause
damage to the starter motor.
• Check the fuel gauge. You may be out of fuel. If the gauge shows that
there is fuel in the tank, the trouble may be in the electrical system or
the fuel system. If equipped with an auxiliary tank, be sure that the
tank control switch is set for the tank with fuel and not on an empty
tank.

 

Yes, an extra tank is a problem for condensation, especially a metal tank and especially a large one that doesn't get kept filled because this air space of damp air going down in temp at nightproduces small amounts of water in the tank. This water then sinks to the bottom and eventually gets picked up and hopefully sets off the water in fuel light.

KPER's language from the manual looks like a hold over from the trucks back in the day which had two fuel tanks and a switch that changed what fueled the truck and read on the gauge. Even in those days with two tanks, you couldn't hold much more fuel, as each tank fore and aft was only 16 gallons if remember correctly. And yes, this is a problem because if you are not using the fuel, you should leave one tank full to prevent condensation. Also, when you are down to half and going to park it, it should be filled up to prevent condensation.

 

Perhaps a little off your question:

2012 chassis cab dually have option of 40 gal aft and 28 gal mid ship factory tanks. This was not available on 2011 Lariat CC or I would have ordered.

Jim

 

I was wondering why there is no stopcock on the bottom of the tank so you could let the truck sit a couple days and drain off the water. You could remove it every couple months and it would never reach the pickup.

 

I really should stay out of this but....


I have ran dual tank configuration since 1983. Some were stock dual tanks from factory and some I have installed. I can't answer if the factory tanks had a manual drain or not.

However all auxiallary tanks I have used do have a manual drain in the bottom with a petcock for draining. My present tank makes it's pickup from the top of the tank, but there is still a petcock for draining or gravity feeding. I have always tapped the manual petcock and the factory drains. I yet to this day have ever had a drop of water.

My truck stays inside and is only exposed to weather when we have the 5th wheel out. I also filter/water separator the aux tank before it enters the aft tank. Religious full time user of Power Service.

I repeat 29 years of some form of dual tanks and NEVER a drop of water. I guess I have been lucky. I am also very careful and visually check aux tank as well as sampling fuel often.

Now, with all that said I don't know if this voids my factory warranty or not. My dealer has studied my hook up and they know I am VERY **** when it comes to service and detail.

Best to all of you and enjoy your GREAT trucks.........



Jim

 

Jim
That a exactly how how have to treat the situation to prevent condensation and drain off a second tank. I think the issue is up north where we get more extreme temperature changes. Condensation only makes a very small amount of water each heating cycle but it can add up over extended periods of time. Stock fuel tanks have never had a drain point other than at the HCFM but the aftermarket in bed tanks do have and you are right they should be used. This condensation issue is exactly why manufacturer don't have 45 oand 50 gallon single tanks like the aftermarket set ups. It's just that much more air space which can condense water into the fuel. When you are pulling and using lots of fuel, this isn't an issue, but when it's a dd and only1/4 tank is used a week in some of these after market tanked trucks, then I think there is as long as a month between fill up which is when condensation can make more water. For us, up notprth, the only time of year is best is when it's below 0 as then there is next to no water in the air, 0 humidity. I would love to have that second tank aft of the axle where the spare tire is, I would just have to keep it full all winter and not use it much unless pulling.

 

I live in NW Washington and have used a 70 aux. tank in the bed of my trucks since the 80's and do get condensation. The only time I keep it full is when going on a trip, so yes that does develop condensation.

I have it plumbed into the overfill tube of the main tank with a external fuel pump that is switched in the cab. I had a water in the fuel seperator incident in my 01 7.3. After that I put a water seperator in the line before it gets to the overflow tube. That solved the water issue. I drain the seperator every couple of oil changes. Some time a little water and some times a couple of cups. I get the most when the time between oil changes is the longer periods. This longer time is due to lack of driving the truck.

Hope this helps