DEF tank

Tsgs69400 · Jan 30, 2017

Well i am sure this has been discussed but here i go anyways.
I went on a diet in October and did not touch the DEF.
What is the general recommendation on the DEF tank. Can I leave it? Does it have to be drained or filled?
Any drawbacks to leaving it?
Thanks ahead of time.

TLyons90 · Jan 31, 2017

I think I have read that most people drain them since the DEF can crystalize or something. Then obviously if your truck ever fattens back up you don't want it clogged and not working. I plan to pull mine here sometime soon just cause I hate clutter and non used stuff.

BK39 · Jan 31, 2017

Your call, I have read it both ways, "drain it, don't drain it". On my 13 I removed it from the truck, didn't drain it, didn't mess with it, just removed it. It sat in my garage for 2 or 3 years, then went back on the truck before I traded it in. No issues, went back on fine.

Tsgs69400 · Jan 31, 2017

Im really torn because leaving it on and draining would be the easiest .
If i remove it then i will have more wires and hoses to try to cap off. I already do not like how many pigtails there are inused down there despite the fact that i sealed them.
The def fluid does not ever freeze does it?

stevens6.7 · Feb 2, 2017

I've read as long as air doesn't get to DEF then it will not crystallize. I've had mine on a diet for about 2 1/2 years and I've left the tank on. It was full when it went on a diet and I have not checked it since lol.

Tsgs69400 · Feb 2, 2017

Ok cool, maybe ill just top it off and reduce the air space in there for the long run.
Thanks yall.

BIG JUICE · Feb 4, 2017

mine is on there. going to top it off after your post. just to remove dead space inside tank, like you said. I'd like to pull it but not worth it, but I also left my passenger valve cover thing in place for now. When I get out of warranty it can all go to scrap yard.

Kxc · Feb 4, 2017

Def freezes around 10 F at the proper concentration. If it's Diluted at all that number will be higher. It's pretty hard to keep it from crystallizing being that it's not going to be used but filling it up is probably ur best bet.

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Tsgs69400 · Feb 6, 2017

I wonder if there is a heater in the tank to prevent it from freezing at sub sero temps?

JetExpress_6.7 · Feb 6, 2017

Yes, the DEF tanks all have heaters to aid in operation in severe cold climates. Now, does that heater function after truck has been tuned I cannot say...

04cr450 · Feb 6, 2017

JetExpress_6.7 said:
Yes, the DEF tanks all have heaters to aid in operation in severe cold climates. Now, does that heater function after truck has been tuned I cannot say...

I want to say no. All emmissions associated should be disabled.
I could be incorrect though... Mike! Where ya at buddy to answer this lol

Tsgs69400 · Feb 7, 2017

This would be a good question for one of the tuners. If they leave the heating element operation in play then good.
But, on a side note there must not be a severe issue with it because in very cold conditions with a truck sitting outdoors the heater would be non operational anyways.

Dzchey21 · Feb 7, 2017

04cr450 said:
I want to say no. All emmissions associated should be disabled.
I could be incorrect though... Mike! Where ya at buddy to answer this lol

Im not sure that's true because I have heard if you don't unplug that module on the right side when you take the *** off it will spray urea out of the line. Unhooking it doesn't generate codes... or at least that's what I was told. I always unplug them.

04cr450 · Feb 7, 2017

Gotcha. I think I know the box you are referring to. UnDer the passenger door on frame? Not why you would leave it plugged in anyway- then the *** wouldn't come out lol still makes no sense. I would think that all of that section/egr/*** would be disabled