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DEF TANK Over Fill

27K views 21 replies 18 participants last post by  powerstrokeshellback 
#1 ·
What is the big deal about over filling the DEF Tank??? I ask because I did just that earlier today. Truck was already soaked as per raining all day long. Washed it off the side of the truck very rapidly but have seen in places {maybe the manual} not to over fill this tank...WHY:dunno:
 
#2 ·
Overflow onto the ground is the main reason I see why not to overflow. Our mechanics always fill the DEF tanks when they change our oil so can't actually say why since I have yet to pour a drop in yet, lol
 
#3 ·
because it crystalizes when it is exposed to air for too long which can damage your paint and or cause the cap to become stuck or frozen due to crystallization around the cap supposedly all urine does this ?? hahaha
 
#9 ·
Don't worry about spilling that crap. It won't hurt paint, shoes, pants, etc. We go through hundreds of gallons of it on the farm (unfortunately) and it's ended up everywhere you can imagine. No ill effects yet. As far as expansion due to freezing; tank is heated and has an overflow. I wouldn't sweat it.
 
#10 ·
I over flowed it on our cab and chassis the other day. It didn't do anything on the ground but look wet and it didn't get any on the truck so can't offer advice there lol. If you don't know how full the tank is and your filling up with them stupid 2.5 gal container how can you tell when to stop. Lol. It's gonna over flow.
 
#11 ·
Thats what I did... Checked my message center and it said under 1/2 tank. So I drove it another 300 miles or so and said ok, it should hold 2 1/2 gallons by now being it is a 5 gallon tank.... Wrong, Of course I was pouring it in quickly thinking it would hold it all with no probs but I was wrong:tard:
Anyway, guessing the warning is waaaaay off and will just wait till it gives me the 800 mile warning next time and maybe it will be perfect...:rofl:
 
#12 ·
I overfill mine all the time. Once I start urinating I can't stop without excruciating pain...so I just let the tank flow over and it spills all down the side of the bed. Oh well, it doesn't freeze too often in Texas.
 
#14 ·
To not over fill it...especially in winter, to prevent rupturing the tank when it freezes.
I just do some quick maths. it holds 5 gal, estimate whats left, then i usually give myself a gallon safety factor.
I have an Edge CTS, so I can see roughly whats in it, but I usually don't add anything until i get the warning. So in winter i add 3 gal when i get that warning.

If freezing is not an issue, fill it up, just listen close....not always easy at noisy truck stops. Or stop when u get 4 gal in it.
For me i'd rather not overflow it and can live with it not right full to the neck.
 
#15 ·
Advice

FYI,


I saw on Amazon that there is a DEF Nozzle from Ford that has a shut off and prevents overfilling. I have not tried it yet, because I have been filling up mine at the Gas pump at Buc Ees when we stop in Waller...
 
#19 ·
My wife's VW Passat diesel had the DEF fill tube in the trunk. If there was spillage it looked like you were trying to grow crystals around the fill neck and surrounding carpeting. I haven't had that issue when I've topped off, and overfilled, the tank on my F-250. Just rinsed it off . . . no crystals or paint damage.

We had a check engine light come on in her car. Diagnostics showed it to be a bad heater for the DEF tank. Apparently the heater and pump were one unit and they needed $2500 for the fix. We opted to let it go as we rarely get temps under 20 degrees here. There is also a fix for the check engine light that involves splicing a resistor in the wiring to fool the system to believe the heater is still operational. As long as the car stayed in a temperate climate that'd be o.k. I guess.

Thankfully, the VW diesel buy-back came through for us and we never had to pay for the fix and got a good amount out of that car.
 
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