Seneca - Extendafill

[RayBo]

Would like to hear your thoughts once you get it running.

[Mark S]

Originally Posted by RayBo

Would like to hear your thoughts once you get it running.

Absolutely. The site said about 3 weeks for delivery I believe.

[RayBo]

Thanks, I'll look to hear from you.

[Mark S]

Originally Posted by Mark S

Absolutely. The site said about 3 weeks for delivery I believe.

Please disregard. It says ships in 1-3 days. I don't know where I got the 3 weeks from.

[Crossingover]

Originally Posted by Mark S

I ordered mine on Saturday. I figured I would fuel up like normal, install the Extendafill at the pump (hopefully nobody behind me) and fill to the top of the original filler hole to see how much additional fuel I can reasonably add.

Please let us know what more you are able to pump in! I wonder what the folks at Freightliner think of all this?


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[Arizona]

Originally Posted by Crossingover

Please let us know what more you are able to pump in! I wonder what the folks at Freightliner think of all this?


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I have problems filling the DEF tank. It doesn't look like this would fit that intake?


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[RayBo]

Originally Posted by Arizona

I have problems filling the DEF tank. It doesn't look like this would fit that intake?


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DEF filler neck is smaller. An easy workaround is to save one of the DEF hoses from your current box and attach it to your new one. (I used duct tape, which I always carry, but I suppose you could use heat shrink tubing.) Now the hose is long enough to invert the box and get it all into the tank easily. There's also the "old funnel trick" but I did that first and found I could not tell when the tank was full and spilled some.

[Mark S]

I find it sooooo much easier, and cheaper, to just buy DEF from the truck stop pump. I keep an emergency gallon or two with me but try to always pump it when buying diesel.

[RayBo]

Originally Posted by Mark S

I find it sooooo much easier, and cheaper, to just buy DEF from the truck stop pump. I keep an emergency gallon or two with me but try to always pump it when buying diesel.

I agree. At home, I use the box. But when my wife is at the rodeo 6 hours away and I'm not there, and she has to go to a regular gas station (not a truck stop) that's why I have the funnel. However, you really want a funnel that's translucent, which is this thing for ten bucks:

https://www.amazon.com/Lisle-17232-R.../dp/B00MEPIU4M

Best wishes.

[Mark S]

Since I have owned the Seneca I have only used truck stops because I like the convienece of the two pumps and the easy access. And having the DEF pump.

When you use a gas station, do you fill one tank and then drive around to fill the other? Always having my Jeep behind me, I am trying to figure an easy way to use a regular station.

[RayBo]

Originally Posted by Mark S

Since I have owned the Seneca I have only used truck stops because I like the convienece of the two pumps and the easy access. And having the DEF pump.

When you use a gas station, do you fill one tank and then drive around to fill the other? Always having my Jeep behind me, I am trying to figure an easy way to use a regular station.

Unfortunately, yes, I do have to drive around because some places we go in "PoDunk" don't have truck stops and we need fuel. What I've taken to doing (because we often pull a trailer and "driving around" fails) is bringing 4 empty 6 gallon diesel fuel cans and filling them up when I do the passenger side. I then walk them around and fill the driver's side. I don't love it, but it works. Also, I usually have some spare, so when I'm parked for extended time, I can fill up to keep using my generator.

By the way, I do have some phone apps that help. Love's tells you how far you are, and I have another called iExit which tells you everything about every interstate exit and what is there. Unfortunately, we're often way out in the sticks and these don't help.

It's a workaround, and I'm seeking a better solution, so anyone with comments please reply.

[Tumbleweed44]

Originally Posted by RayBo

It's a workaround, and I'm seeking a better solution, so anyone with comments please reply.

It seems like we’re back to the larger or extra fuel tank idea.

[RayBo]

Originally Posted by Tumbleweed44

It seems like we’re back to the larger or extra fuel tank idea.

True. I'm still working that angle. I'll post what I do, but for now I'm thinking of 100 gal tank with single fill between the rails.

Still researching. Any thoughts or experience welcome.

[Tumbleweed44]

Originally Posted by RayBo

True. I'm still working that angle. I'll post what I do, but for now I'm thinking of 100 gal tank with single fill between the rails.

Still researching. Any thoughts or experience welcome.

I agree. The 100 gallon would suit me to a T. I am concerned about the extra weight, 800 lbs. or so, I'd guess with the weight of the fuel, tank and mounting bracketry. While the air bags would stop any sagging, the weight would still be there. Kinda like an extra 800 lb. tongue weight.

[RayBo]

Originally Posted by Tumbleweed44

I agree. The 100 gallon would suit me to a T. I am concerned about the extra weight, 800 lbs. or so, I'd guess with the weight of the fuel, tank and mounting bracketry. While the air bags would stop any sagging, the weight would still be there. Kinda like an extra 800 lb. tongue weight.

I'm with you. The configuration I'm considering does not put the tank behind the rear axle, rather it is situated between the rails between the first and third carrier bearings, above/beside the driveshaft. (think long and narrow and oddly shaped.) It's not a simple rectangle, but has a configuration that allows it to clear the brackets that support the carrier bearings and the driveshaft itself.

It will be a bit of a job to install, as it will require removal of the driveshaft and carrier bearing brackets, but for a "one shot deal" I think I could do it in a day's work.

Just for everyone's info, I'm not looking at something "off the shelf." We build boats, and the folks that make our gas tanks are magicians. They can make any shape you can consider. So, putting a 100 gal tank under there is really not a stretch.

The tank will be aluminum, and the only consideration is maybe a heat resistant coating/blanket/device near the DPF. To me, it seems really simple, and also I'm considering two equalization pipes between the big tank and my existing tanks so that I don't have to fool with anything for a separate fill port.

I believe from my tape measure that the bottom of my supplemental tank will be above the bottom of my existing tanks, so gravity will equalize. I also intend to very slightly pitch the bottom of the supplemental tank toward the front of the truck to ensure that it empties into the existing tanks before they become empty. This will allow the truck to use almost all the available fuel. The top of my supplemental tank will be below or equal to the bottom of the filler necks on the factory tanks. Then I don't need separate vents or safety devices.

Rudimentary (early) math says that I can get 100 gal without much trouble, it will just be an odd shape and a lengthy install...but I fear not.

I also think that with supplemental airbags (My 2012 Seneca is spring not air suspension) and with the tank in front of my rear axle, I won't suffer much tongue weight penalty.

I'll post some pics once I get it worked out. I actually imagine there might be a market for it if I become so inclined. 174 gallons at 9mpg gets me about 1,500 miles without fooling with stopping for fuel.

[Tumbleweed44]

RayBo
I had a dually that had an auxiliary fuel tank in the bed, gravity feed. I put an inline fuel filter in the line between it and the OEM fuel tank. I was surprised by the stuff it captured. Just a cheap, clear fuel filter will do.

[tjbroussard]

Couldn't be more pleased with the Extend-a-fil and the customer service. As I learned best to add a few links to the chain if you plan to continues using it per the directions. Gordon was right there to assist as needed in support.

Terry

[RVermont]

I would be happy with just getting the 74 gallons they claim we have. Someone on here actually drained the tank and only filled it back with 50 gallons or so. An extra tank about 20 gallons would suit me just fine so I can get thorough PA with out stopping and paying 15% more then the surrounding states.


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[RayBo]

Originally Posted by RVermont

I would be happy with just getting the 74 gallons they claim we have. Someone on here actually drained the tank and only filled it back with 50 gallons or so. An extra tank about 20 gallons would suit me just fine so I can get thorough PA with out stopping and paying 15% more then the surrounding states.


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I have not verified this guy's comments, but he sounds legit and I'm going to try it myself (with a couple diesel cans in the basement if needed.)

Jayco Seneca Freightliner M2 Fuel Gauge Not Working or Incorrect (I only fill 40 gallons when I should have 75 gallon tanks) | RV Underground

[Mark S]

From reading this forum and experience I know our fuel gauges are very inaccurate. That is why my first accessory was a ScanGauge. According to my ScanGauge my low fuel light comes on after I have used about 40 something gallons of fuel or about 400 ish miles.

My assumption is we have about 60 gallons of usable fuel, or 80% of the 74.5 gallon stated capacity. I use the 60 gallons to set the ScanGauge for miles to empty. I find the ScanGauge to be accurate to about 1 gallon of actual usage. It would be really comforting to know the actual capacity of the tanks but I am not willing to drain the tanks dry and refill to find out.

There are users here who have stated Extendafill allowed then to add an additional 5-7 gallons per tank. If I can add an additional 10 gallons per fill up, which will extend my range by approximately 100 miles and protect my paint around the fuel openings. I will consider it to be money well spent.