My farm store sells DEF for $9.95 a 2.5 gallon jug. That's $4 per gallon that typically last 1000 miles, or less than 1/2 a penny per mile. And if I wanted to buy at the truck stops, As mentioned its less than $3 per gallon from the pumps. Just not worth gambling on home brew for that little of savings. or the inconviences of having to shop at the dollar store and mix the stuff myself.

 

That doesn't mean that someone else won't have a problem, or that you won't eventually have an issue.


The emissions equipment on the 6.7L does not respond well to modifications, contaminates, etc. And although DEF contains ammonia, it is not the same as just mixing ammonia with water.


Play at your own risk, but be aware that repairs to the emissions equipment easily runs into the thousands of dollars, and Ford will not warranty any repairs if certified and approved DEF is not used.

 

well said....been using the API rated stuff and not a single problem in 80k miles.

 

I'd agree with the comments about not taking the risk on a cheap additive.

To clarify some of the points above:

1. Ammonia in solution is not stable and loses ammonia while sitting. Urea in solution is reasonably stable until heated in the exhaust. Plus one can't really get enough ammonia into solution to meet the federal spec, but urea is highly soluble and lets one spray a lot of urea, which converts into a lot of ammonia, once it's in the exhaust.

2. Distilled water is actually cleaner than deionized water. Deionizing will remove certain metal ions but not necessarily uncharged or organic compounds. Of course, one needs to read the label carefully because what is billed as distilled water is often really only deionized anyway. In either case, the water quality isn't an overwhelming issue as long as it's of that general level of purity. It still doesn't matter which is used because this method doesn't work.

3. Unless I'm mistaken about how the chemistry is regulated by sensors in the truck, this method will actually cost you more in fuel.

 

12 bucks at Walmart for the Peak DEF to put in my ~$50K truck every 3-5,000 miles is pretty cheap insurance vs some home brew that;s potentially going to cost a LOT of my money and time to fix. I generally have a couple jugs stashed in my shop and at least one in our 5er and use the oldest one purchased, etc whenever needed first when we travel. I add a jug when the info panel tells me the level is less then 50%

 

OK.... Ya sold me on the extra money for the correct fluid.
Was an idea. My vehicle is out of warranty.
I'm on a fixed income apparently that's way lower than you guys so I'll drop it .

 

Well... If you live in Michigan you know about the short on ramps in the bigger cities and Arizona and new Mexico has on ramps where rapid acceleration is necessary. This will cause you to fill your DEF tank at least once a month. Usually 2-1/2 will fill it and you'll have a little left.
If you overfill your tank and it sprays out IMMEDIATELY WIPE IT OFF ESPECIALLY IN THE FUELING AREA INSIDE THE LID and then use water to wash the area after putting fill cap back on then wipe it off.
Wiping this off inside the fuel lid will prevent fuel contamination.
Trust me....fuel contamination is very expensive so a little extra time to clean the area is well worth the time!

 

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

For those that are keeping DEF fluid stored - I have read in numerous places that the fluid has a shelf life of roughly one year if stored in an area away from sunlight and above freezing.

 

not sure of any long term damage of not using any def at all or the proper kind or what the primary function of def even is to be honest but I live in ND and the first 5 months(14000+ miles) i had my truck I never added any def at all cause im pretty sure it was frozen solid for the duration of the 5 month -20 to -40 degree winter and it never used much if any def at all during that time and it never caused me any problems. I ended up adding around 15 gallons of def during the summer going about the same amount of miles and after a year I did an emission delete so it doesnt matter to me anymore but based on that I kinda doubt using a homemade mixture or nothing at all while tricking it into thinking its using it would cause any problems at least in the short term as long as it doesnt trigger an error code or something. May or may cause possible problems down the road depending on what the actual function of using def is but based on what i know about it I couldnt say what the effects would be for sure.

 

I use about 2-1/2 gallons per two weeks to a month depending on how much I drive.
You'll use more towing and rapid acceleration. If you've ever been in Michigan you know that acceleration is a must on the on ramps because they are so short around Detroit Lansing and Jackson .
Myself, I use my truck to pull my own 5th wheel RV trailer. I travel in the winter to where it's warm so the bones catch a break 😁
But in five months I never had a problem with the home brew.
Def simply mixes and burns off any remaining carbon emissions.
At least that's what Bp says so they can get rid of all the ammonia from refinery 👍
And for the record, Urea is ammonia.
Simple test that's inexpensive.
Mix 1 gallon of pure ammonia with either ionized or distilled water .
Smell the 2-1/2 gallons of actual DEF that you buy at the farm store then smell the mix I described and you'll agree that they smell the same 👍

 

With regard to DEF storage; worth a re-post...

https://www.fcsdchemicalsandlubrican...%20Quality.pdf

Outlines the storage procedures for DEF. Note the "To" line...

 

The chemical formula for ammonia is NH3.

The chemical formula for urea is CO(NH2)2.

They are not identical at all. Urea converts to NH3 in the exhaust, but does so at levels far greater than any amount of NH3 that could be dissolved in water to make the liquid ammonia you buy in the store. Literally a hundred times as much. And liquid ammonia loses its NH3 to the air, while urea is much stabler.

Urea does have a finite life, but after a year, depending on storage, it's only 5-8% or less of the urea that has converted spontaneously to NH3, something driven by heat or UV exposure. But this process is very slow. The SCR measures actual NH3 produced and adjusts consumption based on the actual concentration of urea in the DEF; this means that if you dilute it one to one with water, it will consume it at twice the rate, for example. This is, as you might expect, a control imposed by environmental regs to ensure that nobody hacks the system by using plain water or diluted DEF, and the environmental regs allow very little degradation of DEF. If it goes too far or if the DEF is diluted, you get a code -- at least according to Ford, since I haven't tried it.

And by the way, the DEF tank has a heater to keep the stuff melted in use. It may freeze overnight but the heater will thaw it so it's available for use by the emissions system. So even if one is driving in extremely frigid conditions, as long as you are driving enough to give it time to melt the DEF, it'll be consumed in emissions.

 

Wow, that's a lot of DEF.... Although I don't, I know that I could just have the dealer add at each 6,500 mile oil change and I would be good. I never think about DEF and use only Motocraft brand. The Ford fill spout works perfect. Wash out and return to sealed plastic bag after I'm done.

I spend time in parts of my state where finding diesel is not great. Would hate to need DEF so I tend to fill prior to visiting this area.

Being a person that only uses Motocraft brand, home brew seems so odd to me. Reminds me of stories of people that home brew their own diesel. No thanks. When I can no long afford my F250, I'll purchase a Prius and lie about my gas mileage and what a nice, refined car it is.

Bruce...

 

Interesting that this thread is started by the owner of a truck that is in the midst of having one of the most expensive repairs possible on these trucks, now trying to save what amounts to pennies at best, but at huge risk if it doesn't work. For what it's worth, I am actually in the process of replacing the SCR system on one such truck that IS still within warranty (thankfully to the owner of the truck) under direction by FoMoCo to repair a stubborn P207F that keeps resetting. The cost of this exhaust system is about $4Gs. Not only as a Ford dealership tech, but also a new owner of a '16 F-250 CCSB 6.7L, I consider the cost of DEF to be cheaper than refilling washer fluid.