Ok to top off DEF tank?

[Tfthorp]

Apparently Fords have 3 different heaters 1 in the tank 1 i believe in the pump and 1 one the hose going to the engine. I had an idiot light come on while in Fl. went to the auto parts store and it was a redundant heater for DEF took it to the local dealer it was covered and they replaced it. Four miles later light on again, they replaced another. /didn;t get out of shop and it was on again. Took calls to the factory to let them finally know which to replace but of course that wasn't covered!!!! Was alot don't remember exactly because the AC went out and they had to replace i believe a core or wha ever but the entire dashboard had to come out to replace a $280 part.

[Dave10]

I was told by the Ford dealer that if you get a message that the engine will derate that it will continue to have full power unless it is shut down and restarted. After restarting it will have reduced power.

[Scootsk]

My dealer once told me to let the DEF run under the 1/4 full mark to allow the system to get rid of the old DEF. He said DEF is hydroponic (absorbs water) and allowing to run that low ensures you burn most of the old stuff before adding more. Maybe someone told you something similar

[c214dick]

Ron, how many miles do you get to a tank of DEF when towing and when not?

[mhs4771]

I don't know about DEF absorbing water, BUT it is 66% Water

[Bfisher003]

On our Summer trip of 7,000 miles pulling a (weighed) 14,280 lbs of Montana with our 2018 F-350 diesel I left home with a full DEF tank and by the time I got home with a nearly full tank I had added somewhere around 7-10 gallons of DEF. This trip included quite a bit of mountain driving in Colorado.

[bshgto]

Don`t believe I`ll read so much inaccurate and non factual information on a subject and really proves you can`t rely on any thing you read here. This is worse than a women's sewing Bee.

Told not to top off the tank?
Like one said your ALWAYS topping off the tank. I know I do Always.

Tank will freeze below 16 degrees and crack open
My truck sat outside in well below 16 degrees for sometime, weeks, and
didn't freeze
do you think Ford or the rest would subject this to anyone that lives above
North Carolina..

Don`t fill it all the way up cause (the sun will go dark) and your tank will crack when it freezes.
Just don`t know about this one.

Can`t make this stuff up, really people if you don`t speak facts don`t speak you will lead someone astray and they might repeat it to another that thinks you can`t dump your black tank unless it`s at least half full cause Fred said..............
Read the manual if it`s in there heed the warning if not read this post for entertainment purposes only. Done.

[CaptnJohn]

Originally Posted by Slufoot733

A note of caution. I buy DEF in the jugs. A buddy did the same but fund that someone had poured out the DEF and replaced it with plain tap water, then returned the jug to the store. Now when I buy DEF in a jug I always remove the cap and check the seal to be sure someone didn't mess with it.
As for topping off.....no problem. Just do NOT run out. Those darn computer know when you do and they cannot be reasoned with!

A few Walmart stores have been finding a lot of that. Buy it, use it, refill from the tap and return for refund. Talk about cheap people. I prefer at the pump at truck stops but will buy at auto shops. I don’t do Wally for anything.

[hosssmith]

I have hauled DEF out of truck stop tanks because it was contaminated. I asked how they knew it was bad and the answer was not easy to get but apparently it had been reported by customers with sudden DEF problems that had tests done. I cannot verify that but I can verify that we have removed DEF from underground tanks at two places for disposal.

I would have thought DEF was safe from a truck stop because they sell a good bit of it before I had the experience of hauling it off. We fill our DEF tanks at truck stops because 2.5 gallon jugs would be a pain when one needs 20-30 gallons so we may be taking a chance as well.

That being said we fill our pick ups from jugs that are sealed shut, stored in a cool place, kept out of the sun and come from a reliable parts house. We are helping save the environment one plastic jug and one cardboard box at a time. I expect the landfills love that...

[NormaJean]

The manual on my new 2019 Silverado Duesel sternly warns not to “top off”. The consumption is very much load dependent and the girls guzzle a lot pulling a trailer!

[Bob and Jeannette]

DEF has a shelf life. You moist likely put your note up to remind yourself to keep your def fresh. Google a shelf life by temperature chart to really be amazed, DEF does not last long at higher temperatures. Always decode the manufacture date when you buy your DEF. I have seen 4 year old DEF in auto parts stores on sale.

[Chasnracin]

I pick up my DEF from the Ford dealer. I might pay a dollar or so more for a jug, but if something is wrong with it, it came from them. I try not to let it get much below 1/2. When the "Less than 1/2" pops up on the screen, I throw in another jug. I have let it get to the "I'm gonna derate you soon" screen and once filled, it took several days for the system to reset. I didn't care for that.

[timandsusan]

Def is available in so many locations, I never carry any spare tanks. I see several RVers in this park in Colorado with several DEF tanks sitting under their RV. I wonder how old it is?? Just like checking your tires (I hope you do this regularly), check your DEF level, understand your truck and add as needed. Yes, you will use more towing--just check the level!--IMO

[c214dick]

Thx for the DEF update. My research shows it has a shelf life of one year so it doesn’t make sense, to me, to load up. My only concern is the quality of the DEF while on the road.

[Bob and Jeannette]

Originally Posted by c214dick

Thx for the DEF update. My research shows it has a shelf life of one year so it doesn’t make sense, to me, to load up. My only concern is the quality of the DEF while on the road.

And how long it has been on the store shelf.

[TrailTrackers]

Originally Posted by bshgto

Don`t believe I`ll read so much inaccurate and non factual information on a subject and really proves you can`t rely on any thing you read here. This is worse than a women's sewing Bee.

Told not to top off the tank?
Like one said your ALWAYS topping off the tank. I know I do Always.

Tank will freeze below 16 degrees and crack open
My truck sat outside in well below 16 degrees for sometime, weeks, and
didn't freeze
do you think Ford or the rest would subject this to anyone that lives above
North Carolina..

Don`t fill it all the way up cause (the sun will go dark) and your tank will crack when it freezes.
Just don`t know about this one.

Can`t make this stuff up, really people if you don`t speak facts don`t speak you will lead someone astray and they might repeat it to another that thinks you can`t dump your black tank unless it`s at least half full cause Fred said..............
Read the manual if it`s in there heed the warning if not read this post for entertainment purposes only. Done.

You and I would get along like best friends. I couldn't agree more with what you said. Oh, and you forgot to quote the guy who "thankfully" told us that "ice won't pour". OMG

[twindman]

I wonder if the story of not topping it off is because when doing so, it will overflow to the surrounding are and that stuff is corrosive. Also, on my Chevy, if it barely overflowed, it would end up in the little spout thing and that may be dirty and would find it's way into the tank. And the engine/computer doesn't like dirty DEF!!!

[Bob and Jeannette]

Originally Posted by twindman

I wonder if the story of not topping it off is because when doing so, it will overflow to the surrounding are and that stuff is corrosive. Also, on my Chevy, if it barely overflowed, it would end up in the little spout thing and that may be dirty and would find it's way into the tank. And the engine/computer doesn't like dirty DEF!!!

DEF crystalizes in fuel and can clog your injectors.

[mhs4771]

Here goes another:
DEF never get near the Fuel, it's injected into the Special Converter down stream in the Exhaust!!

[Bob and Jeannette]

Originally Posted by mhs4771

Here goes another:
DEF never get near the Fuel, it's injected into the Special Converter down stream in the Exhaust!!

Unless as the OP wrote it spills into the fuel tube while filling up with DEF. I keep mine tightly capped.