Do yourself a favor sounds like some one put yellow antifreeze in there no such thing about keeping the tank full its not the issue i have been doing that for now 38 thousand miles no bad effect. my dealer has so many problems with customers with Waring resets he's telling them too do what i do ever 4 thousand miles 2.5 gallons full with fords fill spout. one other thing my dealer says he starting to believe in my lock now, so many customer with fuel problems dirt and even sand lol people suck just human nature jealous . Like i said it not going too stop them, but i will know they where their and not start the truck

 

Yes, there is such an issue. Just because you haven't had a problem doesn't mean someone else won't.

That's like a lifetime smoker dying of old age saying that there's nothing wrong with smoking because he never had a problem.

 

lol what ever don't lock your fuel door see what happens,people are so good and respectable. The only thing is he might have a issue due to the little time he drives the truck and siting could be a factor might need to have it pumped out ever year like my neighbor because he only drives to plow his driveway other then that the truck just sits their wast of money but he has tons to throw lol

 

I may be missing something in the last few posts, it would not be the first time. If you are adding a full 2 1/2 gallons of DEF, would you not have an indicating symbol on the display showing DEF status change ? If you have a status change, you should have communication between the tank and the ECM ? If radium has not had a problem, Is he actually letting the system work by indicating a change in DEF level status ? My advice to F.I.L. was wait for a change in status and then add fluid. It should still have a huge mileage safety factor before tank in out of DEF. If I can explain it better to my 75 yo F.I.L., please give me a better explanation. Thanks!

 

Yes, there should be a reset if it sees a level change. However, weird things can always happen, and if it only sees a level change at the halfway point and nothing else, there's still a chance of confusing the PCM.... a very very small chance.

Keeping it topped off where it doesn't see a refill event (ie "keeping the tank full") has a much greater chance of running into a problem.

There is a reason that Ford recommends waiting to fill the DEF until the truck tells you to refill, and not any time before. It's to make absolutely sure the PCM sees that the tank has been filled up properly in order to reset properly. Understanding exactly how the system works and it all makes sense. Attempting to circumvent that system can cause issues. And there's been plenty of threads about the DEF tank being full and it still showing "XX" miles to empty warnings. Some of those are caused by failures and faults with the system, and others are caused by operator error topping off the tank regularly.

IMO if everyone quit topping off the DEF tank, these issues would be cut by way more than half.

 

I appreciate your response on this Pocket. On a 2012, what is the displayed message my F.I.L. should see that has to prompt action to refill the DEF tank? He is old school Ford factory trained mechanic from the late 1960's. In his mind an idiot light of any king is a call to action. I have glanced through his owners manual and told him to wait for the system to tell him a change in status and then top off. In my mind it should take 2-1/2 gallons and the system should be happy and my F.I.L. should be happy. Am I missing something? Should he just add DEF at oil change?

I kinda wish he would just drive it like it was a rental car but with the cost of these truck now days, I understand his thought process.

 

My answer:
If you want to have the best chance at the least amount of problems, fill the DEF when the truck tells you to.... when it's nearly empty. That should be 4.5+ gallons worth.

Other people may offer differing advice, and they might do so because they have never had an issue doing something their way. But what I'm saying is in-line with what Ford recommends. And I've learned over the years that more often than not there's a specific reason why Ford would "recommend" something be done a certain way.

 

My apologies to the dead horse, but I want this to be really clear. The 2012 owners manuals states this.

Importance of maintaining the DEF level
In order for the SCR system to operate properly, the DEF level must be
maintained. Generally, the DEF tank should be filled during the oil
change service interval. See the scheduled maintenance information in
this supplement for more information. However, certain conditions or
driving styles, such as trailer towing or fast rates of acceleration, will
require the refilling of the DEF tank more often.
The engine control unit will monitor the amount of fluid available in the
DEF tank. Running a system check in the message center will indicate
whether the DEF level is ok or if it is less than 1/2 full. A message will
automatically be displayed in the message center when the DEF level is
low and needs to be refilled. When you see this message you should refill
your tank. See Message center in the Instrument Cluster chapter of
your Owner’s Guide for message center functions. For instructions on
refilling your DEF tank, see Filling the DEF tank later in this section.
DEF warning messages and vehicle operations
WARNING: Diesel Exhaust Fluid (DEF) must be refilled when
low or replaced when contaminated or the vehicle speed will be
speed limited to 50 mph (80 km/h). In these conditions, drive with
caution and refill DEF immediately. If the DEF becomes empty or
contaminated fluid is not replaced, the vehicle will become limited to
idle speed only once stopped. In these conditions, be cautious where
you stop the vehicle because you may not be able to drive long
distances and will not be able to maintain highway speeds until DEF is
refilled or replaced.
Maintenance and Specifications
26
2012 Diesel

My F.I.L. should only refill if away from home and the display shows the above message, or at dealer oil changes? Do newer trucks have different wording in the owners manual? Is that the best advice I can give? Thanks again.
Tim

 

This part right here is the key:

The other stuff was "generally" speaking, intended just to give you an idea of normal DEF refill times, which are typically near the length of normal oil changes, depending on how the truck is driven of course.

The truck will always tell you when to fill the DEF. Once it does that, then it's time.

There is other supplemental information, and in later years the owner's manual was updated to be a bit more specific. My owner's manual for my 15 actually has a chart outlining message center readouts and what action to take. Notice that the first time it recommends to refill is at 500 miles to empty:

 

I'm a bit confused here Curtis. How could topping off the DEF tank cause a contamination-related failure?

 

It's not Tom.

Kinda got sidetracked to talking about topping off the DEF tank.

 

I would like to see where anyone has read official word from Ford that we are not to add DEF until prompted... I looked through my owners manual and could not find any such advice.

 

See post #24. That's copied from the diesel supplement. "Customer Requested Action" shows to drive normally until the 500 miles to empty shows up. At that point is when Ford says to add DEF. To answer your question, that's when the owner is prompted according to the official word from Ford, and not any time sooner.

 

Sorry Curtis, but that's not quite what I asked. Those are owner/driver requird responses to prompts. No where does it say (that I can find) "Do not add DEF until prompted".
I asked my dealer if there was any problem with adding DEF before prompting and their response was that they do it all the time and said mine was full after just having been serviced for a TSB on a regen issue. They washed the truck (by hand) also..
I guess there's a lot of conflicting information out there - but it seems to me that is would be pretty dumb to create a system that required being half empty, or more, before you could top off the fluid..

 

I don't really get why you would want to fill it up all the time. If you can't find def in 500m in this day and age i would be suprised. Not to mention you usually have a rough idea when it will need it as it is close to an oil change interval. The stuff is also very caustic and you are just increasing your chances of spilling on the paint every extra fill. Plus as ppl have mentioned there have been trucks that have had issues due to this is why some say not to refill all the time. In the end its your truck and you can do what you want, i personal don't feel the need to handle the stuff x2 as many times. I add two jugs when i get the countdown.