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Old Nov 3, 2017 | 07:53 PM
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Def fluid

I have a buddy who told me his brother has used just plain water for 3 years for def fluid. No problems and I guess he puts something in it for the winter months so it don't freeze. Anyone else doing it ? I read the definition of def says 32.5 percent urea to be considered def seems odd it has a certain number to be labeled def by the EPA
 
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Old Nov 3, 2017 | 08:03 PM
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Your buddy or his brother is full of it, or the truck was deleted to not need DE Fluid.
 
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Old Nov 3, 2017 | 08:05 PM
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You can probably get away with that for a while. But at a cost of around $30 and 5 minutes every 10,000 miles it seems a bit irresponsible to not add actual DEF fluid.
 
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Old Nov 3, 2017 | 08:12 PM
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I just bought DEF from Walmart. About $8 for a 2.5 gallon jug. i am OK with adding real DEF in a $70K truck. The real DEF freezes too I would guess.
 
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Old Nov 3, 2017 | 08:29 PM
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Page 192 of the 2017 Owner's Manual:

"The system has a diesel exhaust fluid quality sensor. Dilution of diesel exhaust fluid or use of any other liquid in the SCR system leads to a diesel exhaust fluid system fault, eventually leading to the vehicle only operating in idle-only mode."

If you put straight water in the DEF tank the truck will lodge a formal compliant.
 
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Old Nov 3, 2017 | 09:18 PM
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def does freeze, which is why these systems suck it back into the tank when it's not running


or at least my peterbilt does, damned thing sounds like a leaf blower is running full speed for about a minute after you shut it off
 
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Old Nov 3, 2017 | 09:20 PM
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I second this. DEF is pretty cheap considering the damage using something your not. SuperTech DEF from Wally World has been working just fine for me. If you wait until you have 1/4 of a tank 5 gallon (2 jugs) will filler' up.

Originally Posted by USSenator
I just bought DEF from Walmart. About $8 for a 2.5 gallon jug. i am OK with adding real DEF in a $70K truck. The real DEF freezes too I would guess.
 
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Old Nov 3, 2017 | 10:32 PM
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This is a 2011 truck. I doubt the guy would lie to me. Why would he is it beneficial to him? No! He's been doing it 3 years I thought it was strange but if you think about it the water is just steaming the cat. What the urea is doing idk. I actually thought it was amonia instead of urea. My guess is got it turns to amonia?
 
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Old Nov 3, 2017 | 11:14 PM
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Originally Posted by Flooringit
This is a 2011 truck. I doubt the guy would lie to me. Why would he is it beneficial to him? No! He's been doing it 3 years I thought it was strange but if you think about it the water is just steaming the cat. What the urea is doing idk. I actually thought it was amonia instead of urea. My guess is got it turns to amonia?
Sorry but it ain't likely.


First problem is DEF equipped trucks have DEF quality sensors. If you put water in the DEF tank you get lights on the dash and then limp mode.

But just for grins let's assume your buddy's brother's truck has a bad DEF quality sensor AND the system can't tell the sensor is bad.

He fills the DEF tank water for some strange reason, and goes down the road, then the NOx sensor is going to complain because without DEF the truck is going to produce excess NOx. That is what DEF does it lowers NOx emissions.

One way or another you're going to get some messages on the dash and eventually put into limp mode.

I guess it is theoretically possible that this particular truck had a spectacular series of undetectable sensor failures and it is happy with water in the DEF tank but it isn't likely.
 
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Old Nov 4, 2017 | 07:46 AM
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Here's a similar thread...

https://www.ford-trucks.com/forums/1...def-fluid.html
 
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Old Nov 4, 2017 | 10:25 AM
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DEF tank has a heater to preclude freezing
 
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Old Nov 4, 2017 | 11:06 AM
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Originally Posted by Flooringit
I have a buddy who told me his brother has used just plain water for 3 years for def fluid. No problems and I guess he puts something in it for the winter months so it don't freeze. Anyone else doing it ? I read the definition of def says 32.5 percent urea to be considered def seems odd it has a certain number to be labeled def by the EPA
And I have a *buddy* just like that!!! But I learned a long time ago to take what he says with a grain of salt.
He welded a tip on the exhaust of his old ‘92 Dodge Cummins that is similar in appearance to the exhaust tips on the newer Power Stroke and he swears it increased his fuel mileage by 20% and raised the HP at least 80HP!!!! But he is still a hoot to be around!!!

Just remember that Buddy isn’t going to have tp pay one thin dime if something fails on YOUR truck.
 
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Old Nov 4, 2017 | 11:11 AM
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Don, you want your exhaust going straight out the back. It will provide additional thrust pushing you forward. Just be sure it's dual exhaust or you will wear your front tires trying to keep the truck going straight. This was also explained to me... true story...
 
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Old Nov 4, 2017 | 06:11 PM
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Originally Posted by Karl4Cat
Don, you want your exhaust going straight out the back. It will provide additional thrust pushing you forward. Just be sure it's dual exhaust or you will wear your front tires trying to keep the truck going straight. This was also explained to me... true story...
Ooooooooookkkkkkkkk!!!!!!!!!!!!!
Thanks for the tip, Rodney!!! Now, maybe we can get back to “Jackhammering”!!!!
 
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Old Nov 4, 2017 | 10:09 PM
  #15  
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So, uh, maybe the guy is peeing in his DEF tank!
 
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