Friday, I took the truck to Jordan Ford to see if they could/would resolve the DEF Fill Problem where we were unable to fill our empty Diesel Exhaust Fluid (DEF) tank then magically, the tank showed full.
The service adviser was as perplexed as I was when I explained the problem. I asked him if it was possible that they had filled the DEF tank when I had the oil changed two weeks ago. He thought it best to discuss the problem with the diesel mechanics before proceeding.
After talking to the diesel mechanics, the service adviser reported that they DON’T fill DEF tanks on the service package I had for the oil change. The mechanics also recommended that I drive the truck another few thousand miles to see what happens.
The way I see it, this is a potential time bomb that could strand me in the middle of nowhere. I need to know that the whole DEF system is working correctly. If you run out of DEF, the truck won’t run.
I pushed back. The truck is still under warranty. I had them run full diagnostics.
No problem found while running diagnostics.
What is really going on? In my mind, the most likely scenario is someone filled the DEF tank at the dealership while the truck was in for the oil change and didn’t report it. Since there was no record, the event didn’t happen.
No way you say! If that was the case, the DEF gauge would have shown full.
The Ford owners manual contains the following:
Note:When filling the diesel exhaust fluid tank from empty, there may be a short delay before detecting the increased level of fluid. The increased level detection must occur before your vehicle returns to full power.
Said another way, there is some time between when the tank is filled and when the truck is able to show the true tank level. If I’m right, the time needed to register a full tank depends on how much or how far the truck is driven and not on time as the wall clock measures it.
Here is my experiment. In three weeks I’ll be returning from an 800 mile trip. Based on my estimate (DEF Level Low – Refill Soon) of 498 miles per gallon of DEF, I should be a able to put at least one gallon of DEF into the tank. Before I fill the tank, I’ll need to get pictures of the DEF gauge. After I fill the tank, I’ll take pictures every time I drive the truck until the DEF gauge shows full.
While researching potential solutions and perspectives on my DEF problem, I ran across Typical_DEF_Usage_Chart.pdf on Ford Truck Enthusiasts Forums > Diesel > 6.7L Power Stroke Diesel > Typical DEF Usage Chart forum posting. The chart shows my estimated DEF usage is in the right range.