# DEF freezes



## TDCruze (Sep 26, 2014)

The tank and lines are insulated and heated. It must freeze completely when parked though as I cannot see how it could run the heat and not drain the battery. It must heat the line once started and get enough flowing for it to operate, it does not consume a large amount so it would not have to thaw a large amount. 

There are several diesel Cruze owners including myself in sub zero climates that have not had any issues with the DEF system.


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## Robby (Mar 1, 2013)

TDCruze said:


> The tank and lines are insulated and heated. It must freeze completely when parked though as I cannot see how it could run the heat and not drain the battery. It must heat the line once started and get enough flowing for it to operate, it does not consume a large amount so it would not have to thaw a large amount.
> 
> There are several diesel Cruze owners including myself in sub zero climates that have not had any issues with the DEF system.


You are correct on all counts.

Rob


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## bigluke (Aug 18, 2013)

That's why you never fill it up to the cap in winter, if it freezes you leave some room for the expansion.


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## TDCruze (Sep 26, 2014)

Good point! Don't want to risk the tank over flowing.


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## Jim Frye (Mar 16, 2011)

TDCruze said:


> Good point! Don't want to risk the tank over flowing.


Or rupturing the tank if it freezes with no air room for expansion.


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## Robby (Mar 1, 2013)

If you buy a gallon def fluid from Chevy it will come (supposed to come with) a spout that has a classy little air tube inside of it.

When screwed to the jug and inserted into the fill hole, it will only allow the tank to fill within one inch of the tank roof.
This is the point the def fluid obstructs the air tube I mentioned and flow then stops.

Nice little setup and clean too.

Comes the question: Will it fit on other suppliers bulk gallons?.......and sadly, I do not know.

But I thought I'd tell ya'all about the fill spout thingy.

Rob


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## TDCruze (Sep 26, 2014)

Here is an interesting article about DEF and the concerns about it freezing in cold weather. 

DEF Freezing


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## Su8pack1 (Apr 17, 2014)

TDCruze said:


> Here is an interesting article about DEF and the concerns about it freezing in cold weather.
> 
> DEF Freezing


Good article. Thats something I had never given a thought to.


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## TDCruze (Sep 26, 2014)

I read in the manual that the tank should not be filled past the point where it meets the bottom of the filler neck. Do not top off! I lifted the cover up tonight to look at my tank and there is a built in high spot in the tank to give room for expansion as long as the tank is not over filled. There is a risk of it cracking if there is no room for expansion. There also is really not that much insulation around the tank and it is not even completely covered. 

I have to say the tank the way it is, is not an ideal design as it is hard to see how full it is when filling, I think Robby has a good idea there with the air lock fill tube. I used a long funnel and stopped filling when I could see fluid at the bottom, but it was a bit tedious.


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## PanJet (Jun 18, 2013)

TDCruze said:


> The tank and lines are insulated and heated.


This is what I originally understood, but are we sure the lines are heated? I have since learned that upon shutdown, the system pumps the lines clear of DEF back into the tank. I would think the lines are at least insulated, and perhaps even heated, but since I learned this second fact, I have been curious if the lines are actually heated.

Also, from what I understand (someone please correct me if I'm wrong), EPA regs allow a certain amount of time before full-system performance is required upon startup in conditions where the DEF will be frozen. This allows the frozen DEF to be heated and start flowing.


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## TDCruze (Sep 26, 2014)

I have looked at the line under my car and it is wrapped with some sort of insulation. I would think in order to operate at all in colder climates the line would have to be heated or the DEF would never flow. I imagine the purge of the line is just to prevent it from splitting like a frozen pipe would if full. 

I have heard about he EPA regs allowing the system to temporarily be offline when thawing. I am guessing this is because it takes a while when frozen to get the system warmed enough to be safe to run. If it is -40F/C and the car is outside it will take a while to safely heat the lines so DEF can flow again and to thaw out a bit of the tank.


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## boraz (Aug 29, 2013)

2014 Chevrolet Cruze Parts -

cant really see any electrical connections on the feed line


our trucks at work lines that have plugs at the end to heat them


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## diesel (Jun 8, 2013)

boraz said:


> 2014 Chevrolet Cruze Parts -
> 
> cant really see any electrical connections on the feed line
> 
> ...


The feed line is pretty expensive


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## karter59 (Feb 14, 2014)

There is a line heater and a tank heater. They are on separate electrical feeds from the DEF controller. The system does reverse the DEF pump and opens the DEF injector to purge the DEF line after shutdown.


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