DEF difficulties

[CThomsen]

Went to fill the def tank for the third time today before leaving on a 2000mile trip tomorrow. Temp -10F. fluid came pouring out the fill tube so I figured it was frozen. Drove the truck for about an hour, filled with fuel and came home. Tried again to fill def and it would only trickle in. It took over 10 minutes to get 2.5 gallon jug in. This is the first time ive had any problems filling def. Any ideas why?

 

[Kirwin]

It fills very slowly due to the tank's vent restriction. At the current temperatures in Indiana, I would suspect that the DEF in the tank was a semi solid slush. Its genneraly accepted on here that the DEF tank should not be filled >1/2 full in cold temperatures due to potential freezing of the DEF. Hope this helps. Ken Irwin

 

[CThomsen]

From what Ive read, def expands 7% when frozen. I was under 1/4 tank and was trying to add 2.5 gallons so I wouldn't have to do it on the road. I thought an hour of driving would have melted the def in the tank but maybe the top of the tank isn't heated well and I had slush near the filler neck. Can't wait for 60+F temps in Oklahoma!

 

[Kirwin]

From my service manual, the DEF heater is in the plumbing lines and in the DEF pump assembly. I'm not sure if the system could overcome, at the very cold temperatures you are in, to raise the temperature of the bulk fluid to allow much melting or how long it would take before you would have liquid DEF for the pump to work with. Maybe someone on here has some better information. As I understand it, the EPA allows the system to freeze and recognizes that the emissions may not work in extreme cold temperatures due to the frozen state of the DEF.

 

[mwilson]

We have seen a few issues with DEF this winter. No issues at all in past winters.

There is a brass elbow on top of the DEF tank used in Freightliner applications that will freeze up and stop DEF flow at -20 below or so. They are engineering a solution at corporate, for now there is a temporary repair that is being used by the dealer body. The rest of the system works flawlessly, just the damn elbow freezes up.

The Fuso's have begun to have issues with frozen DEF in the tank, this is new and there is no solution at this time.

I believe that this extended cold weather is bringing out the weak spots.
There is an Arctic blend DEF fluid made by TerraCair that we looked into, then we discovered that it is not legal for sale in the USA or Canada. The EPA may have to allow some kind of winter blend DEF if these cold winters continue.

Mike.

 

[CThomsen]

I thought the whole tank was heated not just the lines. That would explain why I had such a hard time. Thanks for the info.

 

[mpaulson]

I thought the whole tank was heated not just the lines. That would explain why I had such a hard time. Thanks for the info.

I'm pretty sure the tank is heated or it wouldn't work for about 5 months up here in Alberta. we function in a normal manner here with weeks between 30F degree and -40F degrees sometimes. I've only had the truck since early Dec. but have had no problems yet. We had three days straight of -20F to -38F and I had no problems. my drive to work during that time is only about 8 miles and 13 minutes of driving, not nearly enough time to thaw out the system. the Manual says that about 80 kms or about 50 miles of driving is required to thaw out the system.
I wander if some sloshed up into the filler neck or vent tube and froze in layers in there restricting your flow. I know the filler neck isn't heated since I've spent a fair bit of time looking at the filler necks trying to figure out how I'm going to plumb in my aux tank since the fuel lines are all steel right down to the top of the tank. The DEF lines are plastic there though I believe. I've only had to fill mine once so far and it was around freezing at that time, not well below.

 

[Kirwin]

The tank is heated by the fluid being circulated by the pump. The pump is located inside the tank and the pump and lines are heated, the question is how long after starting the truck does it take to liquify the DEF tanks contents if it is frozen solid?

 

[Kirwin]

mpaulson I cut a section out of the metal vent tubing with an abrasive wheel. Then I added I piece of rubber hose and put the y fitting in for my Transfer Flow. I did disconnect the hose from the fuel tank first and made sure it was very clean before I reconnected it. Not a problem. I'll try to post some pictures of my set up for you.

I'm pretty sure the tank is heated or it wouldn't work for about 5 months up here in Alberta. we function in a normal manner here with weeks between 30F degree and -40F degrees sometimes. I've only had the truck since early Dec. but have had no problems yet. We had three days straight of -20F to -38F and I had no problems. my drive to work during that time is only about 8 miles and 13 minutes of driving, not nearly enough time to thaw out the system. the Manual says that about 80 kms or about 50 miles of driving is required to thaw out the system.
I wander if some sloshed up into the filler neck or vent tube and froze in layers in there restricting your flow. I know the filler neck isn't heated since I've spent a fair bit of time looking at the filler necks trying to figure out how I'm going to plumb in my aux tank since the fuel lines are all steel right down to the top of the tank. The DEF lines are plastic there though I believe. I've only had to fill mine once so far and it was around freezing at that time, not well below.

 

[mpaulson]

mpaulson I cut a section out of the metal vent tubing with an abrasive wheel. Then I added I piece of rubber hose and put the y fitting in for my Transfer Flow. I did disconnect the hose from the fuel tank first and made sure it was very clean before I reconnected it. Not a problem. I'll try to post some pictures of my set up for you.

Thanks Kirwin, I've been thinking of doing that, but with everything connected as one unit, I have been thinking that it will be a pain to remove the filler neck as well as getting to the clamp that is quite a way in over the frame rail and over the tank. The vent hose was 3/4" i.d./3/4" o.d on the pipe, right? I can see a "3/4" in the picture. Mine would only be a single line tied in. I assume that the second hose is for a vent while transferring fuel? Is yours a gravity feed? Mine will have a pump to transfer the fuel.

 

[RikDavis]

Kirwin
Thanks for the pictures.. I have the same situation as mpaulson above and am using a pump also as I salvaged the transfer flow from my 99. Right now I just stuff a line from the aux tank in the filler and use a timer like a bathroom fan would use but I do need to plumb it in permanently when the weather gets better (-5 in TN this morning). I will just live with the current set up while we head south.
It does look like a pain to remove the entire filler assembly. Looks like it would be good to remove the plastic wheel well to get some working room

Rick

 

[Kirwin]

Yes it is 3/4 inch hose and no its not gravity fed, my Transfer Flow system was built in 2005 and the design was different back then. One line is the supply from the Transfer Flow pump and the other line is a direct vent line that goes back to a vent connection on Transfer Flow fuel sending unit closure. In other words there are 3 hoses (only two of which are visible in the picture): 1 runs from the fuel pump and subsequently to the tee in the picture, one is a vent that runs to the same tee and the last one connects to a separate penetration in the top of the Transfer Flow tank via a rollover valve and is just open to the atmosphere under the truck near the tees location. My thoughts are that this was probably needed for a gas application that Transfer Flow was selling back then for emission purposes but was not needed for diesel fuel.

When I did my install I was able to disconnect the steel vent line from the tank at the hose clamp that attaches the steel vent line to the hose jumper that connects to the fitting on the top of the fuel tank module (NOTE: I disconnected the end that is close to the filler tube, not the one on top of the tank). After that I sealed both ends I disconnected with plastic bags and a zip ties then put some cardboard around the larger fuel filler pipe for protection and used a die grinder with a cutoff wheel to cut through the steel vent line in two places, removed about a 7 " section, cleaned up the edges, and wiped/blew out all the grinder dust. Then I installed the hose, cut it to length, and cut out the section for the plastic tee, then finished it up with some SS hose clamps. I did all the work from under the truck, I did not remove the fuel filler from the truck. There is enough room as long as you protect the larger fuel filler tubing when you are cutting the vent tubing.

Thanks Kirwin, I've been thinking of doing that, but with everything connected as one unit, I have been thinking that it will be a pain to remove the filler neck as well as getting to the clamp that is quite a way in over the frame rail and over the tank. The vent hose was 3/4" i.d./3/4" o.d on the pipe, right? I can see a "3/4" in the picture. Mine would only be a single line tied in. I assume that the second hose is for a vent while transferring fuel? Is yours a gravity feed? Mine will have a pump to transfer the fuel.

 

[MelvinPierce]

Anyone install the gravity feed system that cuts into the larger fill line?

 

[PMcCall]

I filled my DEF up about 2 weeks ago and its been readong as full ever since. I drive about 400 miles a week just back and forth to work. Thats about 50 miles each way so I dont think the thaw in 50 miles concept works I am starting to worry a bit if its frozen, will the pump eventually burn up?

 

[Kirwin]

Although I don't know for sure, from the description in the service manual, the temperature sensor is located in the DEF pump module. The pump is controlled by the DEF Dosing Unit as I understand it. It knows that the DEF is frozen based on temperature so I would the think the engineers would prevent pump operation until the heaters had melted enough DEF in the pump cavity for it to operate. The pump is pulse width modulated based on pressure output so the electronics certainly has the ability to sense motor current so if the pump was still locked up due to ice crystals I'd think the electronics would turn it back off for a set period of time and then recycle the pump to check for proper operation. The lines are also heated and as they are much smaller, I would think that the fluid present in the lines would melt before the pump would come on line. The question is how long does this take at -15? -25???? Your guess ask as good as mine. As far as reading full there is another tread on here that explains that there is not a float in the tank due to this freezing issue with the DEF. The electronics guesses at level until it drops to about 50% then the system uses a sonar based probe system to read actual level. I guess the sonar based system doesn't work well when the tank is near full.

 

[CBari]

Kirwin, on your aux tank set up what happens if you forget to turn your pump off with the no fuel cap set-up on the 13s. I have got an aux tank out of my 03 that I need to plumb in. Also what kind of pump are you using.

 

[CThomsen]

When I started truck today def gauge still read under 1/4. After driving for 15 minutes (5F temp) gauge jumped almost to 3/4 so it must have thawed and is now reading what I put in yesterday. Heater must be working well.

 

[mpaulson]

I am going to have a red/blue flashing led light that I'm going to mount on the dash up high where it will annoy the heck out of me that will be wired into the pump wire so that when the pump is on, the light will flash alternating red/blue so that I don't forget about it and shut it off when the gauge reads right on the full mark. That way I know I'm safe since you can fill to the gauge reads above the full mark. In my case I'm using the aux switches that are in the dash and using #2 since it does not have a memory function and when you shut the truck off, it goes off and will not come back on when you restart the truck unless you press it again. This should be idiot proof as long as the light annoys me.
My one concern is that if I use the Geno's cap plug that I have, I probably should do the two hose system that you show and run the upper one to the top of the tank in the box so that the air can vent back to the aux tank and not inflate the trucks tank since it may not be able to vent fast enough as the fuel is pumped in. There is that extra little 1/4" or so hose that comes up from the tank to just under the filler mount that I assume is some sort of a vent for the oem tank as well, but it may not flow enough air with a 140 GPM pump pumping fuel in and with the Geno's cap plug in place.
The pump that I'm using is a Holley 712-8151 black electric marine fuel pump that flows 140 GPM at 9 psi. I am also putting in a 2 psi check valve to prevent it from siphoning after turning the pump off.

 

[mpaulson]

When I started truck today def gauge still read under 1/4. After driving for 15 minutes (5F temp) gauge jumped almost to 3/4 so it must have thawed and is now reading what I put in yesterday. Heater must be working well.

Sorry, I kind of hi-jacked your thread. glad to hear that your issue resolved it's self as it should with heaters functioning properly.

 

[Kirwin]

CBari, mpaulson, my system uses the Trax II from Transfer Flow. This unit has a microprocessor that reads both the main tank level from the OEM sending unit and the aux tank level form the Transfer Flow sending unit. It energizes the pump as necessary to maintain the two tanks at equal percentages. See their webpage for a better description http://www.transferflow.com/products/Trax-II . The pump is part of my Transfer Flow system. Its nothing special, it is also used on Onan generators. The pump only flows about 1 GPM but it doesn't take much. The controller energizes the pump and shows "pump on" in the display so you know its transferring fuel; that, along with the fact that the display shows the levels in both tanks makes the system very user friendly. When it not transferring fuel is shows "OK" and tank levels. Best of all is it's all automatic and the module corrects the trucks fuel gauge to show total fuel level. The 1/4" line you see under your truck is indeed a vent line for the main tank and if you fool around and add too much fuel to the main tank fuel will come out of it. Don't ask how I know this it wasn't pretty. I think you may mean 140 GPH on your pump. 140 GPM is lot of flow! Ken Irwin