I posted this in the general diesel section, but there does not appear to be any takers there - so.....

I've owned and worked on a number of diesels over the years, but the truck I have on order is my first ever diesel that requires DEF.
Since the length of this truck almost spans two zip-codes, it will be spending most of it's life outside.
Last winter was one of the record breakers here in MN. Sub-zero weather for weeks on end.
For those of you not familiar with out lovely state, -30f is not all that uncommon. I have seen as cold as -52f.

My question is - what happens to the DEF and its pump/feed system if it freezes?

 

All the components are heated to thaw the DEF out (tank, line, and pump). Never had the truck complain in those temps.

 

The DEF freezes and sometimes it will just stay frozen the whole time. There's heat trace on the lines but in very cold weather it may never thaw out during a trip.

I removed the DEF tank from my truck in the winter time and the contents were frozen solid. It took about a day in a heated shop for it to return to liquid form... then I couldn't figure out how to empty the tank so now it sits, I guess.

 

Randy good question ! But it won't be an issue, But it will freeze at 12deg F. You can just drive it and not worry about all that stuff. Or when its out of warranty if you still have it, Delete it !

 

Trent's post is one that really is related to my concern here..

If it is frozen solid, it is inoperable. If it is inoperable (or empty) I understand that the truck will be speed limited and to the pint of not being able to go more than 5 MPH.
This is a concern..

Also of concern is that when water or other solutions freeze, they expand. When they expand, they cause a hardship on pumps, fittings etc. Will this cause failures down the road for me and others?

There will be times when the truck will sit for up to a month without being run in the winter.

Thanks guys!

 

Thanks Tim - I did not know it could be deleted! We don't have emissions tests here in MN anymore.. So I take it that I would void the warranty if I took it off? How do you tell the computer to ignore the DEF?

 

The truck knows it's frozen and just doesn't use it (somehow).
It should not go into limp mode.

The only concern is over filling the DEF tank in the winter. But I don't think you can over fill it if you use the spout .....

Thousands of stock trucks up here with no issues

 

Now you will get lots of takers on this subject !!......H&S....And spending$$$

 

Randy, you're in good hands with Darren good luck !!

 

There is a heater in the DEF tank, inside the pickup reservoir where the level sender is housed. It heats the DEF inside the pickup reservoir so that the system will continue to operate.

The temp sensor in mine has been on the blink for about 60,000 miles and it has finally failed completely and I am working on getting it replaced.

 

Pics of the heater/sender assembly are here... https://www.ford-trucks.com/forums/1...mbly-pics.html

 

I was told that while the DEF tank is frozen the call for DEF is haulted by the computer and even the EPA knows you can't get milk from a frozen cow. The truck doesn't use the DEF and the regens could be more frequent depending on the amount of passive regens the truck see (driving style or city vs highway driving). As much as I'd love to tell you this is a reason to delete your truck, it's not. A frozen DEF tank just isn't going to hurt your truck other than you getting DEF on the side of your truck if you max fill it and it freezes and gets all over the outside of your truck as it expands. Good idea to just keep it at half full during the freezing temp months.

You should delete your truck for other reasons, but not this one

 

Boy, talk about opening a can of worms....

I'm not looking at deleting yet, but those two statements got my gears whirring....

How exactly does the truck know the temp's too cold to initiate DEF use? An ambient temp sensor? Why couldn't we use that signal to our advantage? Is it just a simple resistor inline to the computer, to fool it into thinking its colder than it is, and effectively turning off the DEF system? How's the truck to know it's not operating 100% of the time in the Arctic Circle?

Discuss....?

 

Sorry Chuck, I tore all that crap off my truck Dec 2010 and have not thought about it since. I do not know

 

lol

Dammit Darren