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Discussion Starter · #1 ·
I'd like to get a better understanding of just what the automotive engneers at Ford intended when they designed these "submersible" DEF heaters that are used across the Powerstroke line. So let's explore it a bit:

As everyone here knows, water freezes at 32 degrees F above zero, and DEF (Diesel Exhaust Fluid) freezes at 12 degrees F above zero. So, if you live in the north country, where winter temperatures routinely fall below zero, and your truck is routinely parked, with the ignition off, outside, overnight (or for any extended period of time), your DEF tank and the fluid it contains, is a solid block of frozen dilute urea. This is basic, factual, high school physics, and despite feeble efforts by some, it cannot be disputed. Park it at sub-zero temps and it's frozen, period!

More importantly, the injection line and the DEF heater itself, with it's metallic fluid-level sensors and internal heating element(s), which is fully or partially submersed in that DEF fluid, is also frozen inside (submersed in) that solid block of ice. This would also seem to be rather self-evident. And so, when that truck is started the following morning, presumably, there is NO "liquid" DEF immediately available to be injected into the exhaust/emissions control system, right? So what happens?

1) Assuming the DEF heater is still working, how quickly does the heater produce liquid DEF?

2) Wouldn't the repeated freezing, thawing and refreezing of the entire DEF tank, DEF fluid and heater, on an almost 'daily' basis, be expected to prematurely damage that heater, and it's sensitive components?

I had my factory (OEM) DEF heater fail the very first time it had ever been exposed to sub-zero temperatures overnight, at just 13,400 original miles, and I see numerous accounts of other owners, who have also had to replace their DEF heaters after cold winter temps, only to have them fail yet again, in short order.

So let's talk about it. What were the designing engineers thinking when they developed and employed a "submersible" heater? Convince me that my next (replacement) DEF heater stands to be more reliable. Convince me that these heaters aren't an inherently defective or faulty design! 馃槥
 

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Business dept - the govt gave us these mandates to sell trucks
design dept - we can add this system but it freezes at 12*
Business dept - so we can sell trucks
design dept - yep
Business dept - ...
design dept - ...
Business dept - ok then, sounds good.
 

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Discussion Starter · #3 ·
Business dept - the govt gave us these mandates to sell trucks
design dept - we can add this system but it freezes at 12*
Business dept - so we can sell trucks
design dept - yep
Business dept - ...
design dept - ...
Business dept - ok then, sounds good.
馃槀馃ぃ馃ぃ馃ぃ馃ぃ馃槀馃槀

So-so true!
 

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I'm not up in the completely frozen north like you but I am here in West Central Missouri and we see cold temps in the winter on a fairly regular basis. I have had my 2016 for 2 winters now and parked outside and haven't had an issue other then it saying my tire pressure was low because if the temp fluctuation. My truck has 86k on it now.

As you stated in your other thread on this subject you admit you overfilled the def tank and then it froze up. Also the fact that the DEF heater only had 13k and some change on it doesn't negate the fact that it was almost 10 years old. I get your frustration with it and I feel for you. I also don't want it to be on my truck or happen to my truck but have just come to terms with it. WHEN it happens I will fix it and I will go on with my life.
 
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I think the direction here, from the previous thread, is that the in-tank design is very flawed.

Ideally the fluid should have a lower freeze point or the tank insulated.

OR

Is there a software design that accommodates for total freezing of the system?
 

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When the engine block heater if equipped is plugged in, does that also operate the def heater? Would make sense to me for that to be the case.


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Discussion Starter · #7 ·
. . . As you stated in your other thread on this subject you admit you overfilled the def tank and then it froze up.
Thanks for feedback on this, and you're largely right in what you've said here. However, we want to be careful in how we word things. I did in-fact feel that I had possibly overfilled the tank, because an attempt to put fluid in, led to immediate spillage, which seemed as though it was an "overfill". However, it's important to note that the fill attempt was done at 20 below zero, immediately after a night of temps well below that, so there's no question that whatever the fluid level had been, it was fully frozen at the time. So there easily could have been a plug of frozen water or DEF lodged in the fill spout. Secondly, and most importantly, the DEF tank has since been removed, and to my surprise, the fluid level was less than half full, which eliminates the possibility of an overfill on that morning in question, since the truck has been essentially parked, in the garage here, ever since.

In addition, when removing and inspecting the DEF tank here recent, I discovered another striking anomaly that could have caused some issues. The rubber fill spout hose that leads up and over the frame, from the trap door, down to the actual tank itself, had several minor kinks in it, but it had one significant kink (almost fully bent), just above where it actually entered the tank. That bend, was literally blocking off 50% or more of the hoses natural (~1.5-2.0") diameter. Could that have caused some issues in filling? Hard to say. But I can tell you that I've rectified it, by wrapping the bended portion in electricians tape, and installing a standard round hose clamp over the top of the tape, right at the bended portion, tightening it ever-so-slightly, until the hose was forced to be round, rather than bent.

Anyway, you're absolutely right. Its a matter of just sucking it up and coming to terms with it, but the design of it, remains a concern to me, and here's why . . . unlike you and probably most others, I'm not gonna fix this thing multiple times. In fact, if this ***** fails on me again in the next 2-3 years, this truck is toast,! It's gone, plain and simple! I just don't have time (or money) to repeatedly play with inherently defective products. Of course, your mileage may vary, and I fully respect that. Some folks have nothing but time and patience. Unfortunately, that ain't me.
 

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Discussion Starter · #8 ·
When the engine block heater if equipped is plugged in, does that also operate the def heater? Would make sense to me for that to be the case.


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No, I'm quite certain that it does not. I've got dual block heaters on mine, and they DO generate some heat, especially in the garage, but outside, at -25 degrees, with or without plug-in? Game over!
 

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If you're selling your truck when this happens again shoot me a PM because that low mileage 6.7 will be a gem! haaaaha.

No engine block heater does not heat DEF. Its not in the engine bay.

I find it concerning you had a big kink in your fill hose... If you are positive those kinks were there before you starting moving it and dropping the tank and no work has ever been done to your DEF tank before that's quite strange...
Should not have been like that. Definitely could lead to the DEF spillage if it wasn't being poured super slow.

No convincing can be done my man. The low mileage is unfortunately not a big factor in this case, its still not a new part. People who don't experience sub zero temps have heaters go bad. I love my Ford so I'll forgive them haha. I also agree with Heavy the design isn't amazing even in ideal conditions. A cold weather package should include a tank heater wrap like batteries can have or holding tanks in RV's. Or a DEF safe anti freeze additive like for fuel. I do not know how long it would take the heater to thaw a block of frozen DEF but probably not right quick. I have no hard evidence but my thoughts are that the thaw and refreeze of DEF wouldn't destroy the heater that easily if you did not operate the truck during those weather conditions. So a solution could be don't use the truck when its freaking cold. But that's a stupid solution. It's supposed to be used. So yes, not a design that stands up to real severe weather. Maybe you could fashion your own heater for the DEF when its freaking cold and you're needing to use the truck. Kind of like how you can wrap hoses in heat tape for RV's camping in winter. I mean its simply super freaking cold where you are talking about haha. The emissions systems have come along ways the last 10 years but there are just some areas that the emissions systems have not been flushed out in less common usage conditions.
 

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The larger machines I work with use engine coolant to heat the DEF tank -- the smaller units use the electric heater
only a small amount of DEF needs to be defrosted -- the heater is near the pump inlet
the main system will be off line until the heater has warmed the tank to above freezing

The system sucks the DEF back out of the lines and injector, when the shut down sequence is started
listen to your truck after you turn the engine off, you should hear the pump reversing so the DEF is all back in the tank
this keeps the lines and injector from getting frozen in the winter, and from making crystals the rest of the time
 

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No engine block heater does not heat DEF. Its not in the engine bay.
I realize that. My thought was the possibility of once plugged in, the main electric line split and also powered the DEF heater. One plug powering 2 heaters by splitting off. Hope that makes more sense.


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It looks like there is enough space between the tank and shield to add a battery blanket.
 

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I'd like to get a better understanding of just what the automotive engneers at Ford intended when they designed these "submersible" DEF heaters that are used across the Powerstroke line.
No, I'm quite certain that it does not. I've got dual block heaters on mine, and they DO generate some heat, especially in the garage, but outside, at -25 degrees, with or without plug-in? Game over!
Ford didn't design these things. It's probably the same company that supplies them to all the diesel automakers (or to those with in-tank pumps). Just like Ford didn't design the cameras, seat motors or fuel pumps.
These trucks will start in extremely cold temperatures without being plugged in. There are a ton of videos showing it. That was a big thing when the 6.7 came out I guess. Guys showing the oil temp at -15掳 not plugged in and starting in seconds. I'd rather have a transmission heater if anything.
You may as well sell while the selling is good and buy a gasser. Things are going to happen with the systems required in modern diesels. Especially if you have one that did a lot of sitting in it's life.
 

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Discussion Starter · #15 ·
I want to take a minute here to try and clarify a few things that appear to have been misunderstood by some, and hopefully this will give folks a better understanding of the truck in question (a 2015 F350), and the pattern of it's usage.

First off, the truck was purchased new in November 2015, and the DEF heater failed this past February (2021), so the truck is NOT 10-years old, as stated by @kbnw15 earlier. It's barely 5-years old.

Secondly, from the day it was purchased, 90% of the truck's usage has been in the summer months, primarily for local camping and boating activities. Up until those nightmarish temps of last February, it had virtually 'zero' use during the winter months, and this is why the odometer mileage on the truck is so low. And each winter, the truck sat idle, in the warm(er) garage, with block heaters plugged in, so it's doubtful the DEF or the DEF heater had ever frozen prior to that one episode.

Thirdly, regarding the kink in the rubber DEF filler hose . . . the truck was sold brand new. There's no doubt about that. So no one could have ever monkeyed with it or replaced anything under there, and over the half-dozen or so times that I had ever added fresh DEF to the tank, the fluid flowed into the tank just fine. No issues noted, despite the kink. Could a small ice blockage have formed and lodged in that kink, once the temps reached those -25/-30 extremes that night? It's certainly possible, but as I said earlier (above), the tank itself was less than half full at the time, as witnessed at the time of tank removal this past weekend.

And lastly, I think @Bhelm has it exactly right in his posting above. I think there is a very strong likelihood that the DEF heater would have survived the extreme temps perfectly fine, even when and if fully frozen, as long as the truck hadn't been operated. In other words, I believe that the DEF heater in my truck likely failed, as soon as I fired it up that first frigid morning, after having been fully frozen at -25 degrees for 8-10 hours in the outdoor parking lot. Of course, I was 500 miles from home, and those temperatures weren't going anywhere anytime soon, so I had little choice, but I'm reasonably certain that had I avoided starting the motor until the DEF had thawed, my DEF heater probably would not have failed. That's just my gut feeling on it.

Anyway, thanks again to all who have contributed their thoughts and opinions on this. I appreciate all of you!
 

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these same issues plauged the class 8 industry and the problems chasing sensor and issues they had un fixable problems would go on and on , i think a lot of this tech used was push to hard and fast and lacked real world testing not that i think it is completly flawed just be a long journey getting the bugs out right and figured out, why cat walked away. best of luck on tracing the gremlins
 

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Discussion Starter · #17 ·
these same issues plauged the class 8 industry and the problems chasing sensor and issues they had un fixable problems would go on and on , i think a lot of this tech used was push to hard and fast and lacked real world testing not that i think it is completly flawed just be a long journey getting the bugs out right and figured out, why cat walked away. best of luck on tracing the gremlins
Many thanks, and yeah, I don't expect I'll find too many more "gremlins" at this point, but I can tell you this much . . . whenever this truck is exposed to winter temps of 10-degrees or less for a prolonged period, I'm gonna assume the DEF is fully frozen, and I'm gonna use an alternate vehicle, or walk REAL-REAL softly before starting it.

In the meantime, I'm gonna look into this idea of installing an external heat tape (or the like) on the DEF tank. I think it's an excellent idea and fully plausible. It won't help a lick if you're stuck out somewhere, where there's nowhere to plug it in at night, but otherwise (like when it's forced to be parked out on the driveway here at home, etc.), I think it could truly minimize some of the winter risk. :rolleyes:
 

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i am not too famulir with those systems i will say but there has to be a solution out there i dont know what they are using or doing in the class 8 market may give you some ideals like the guys running in extreame temps. i over built my truck for the cold but it is old truck cause i had enough of those headaches on my pete , good luck
 

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Discussion Starter · #19 ·
Obviously, colder temps like those referenced here are not common, but then again, they're not really un-common either, depending on where you call home.

I lived in Alaska back in the 80s, and up in Barrow, Deadhorse, Tok, Fairbanks and places like that to the far north, truckers, airport cabbies and others who relied heavily on their vehicles, would leave them parked and locked, but left running through the night, just to avoid freeze-ups. Both gas and diesel engines, because winter lows were often -45 to -60 degrees below zero back then. One winter (I think it was '87 or '88?), it was reportedly -105 degrees F in Kotzebue, and I think I can say with confidence that this current-day DEF heater design would not survive that environment.
 

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Should hunt for members up there to see what happens to them.
 
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