DEF usage ?
More Turbo
Joined: Sep 2016
Posts: 618
Likes: 6
Its directly tied to fuel consumption. Its a 7.5 Gallon tank. You'll get 250-300mpg if your towing heavy. We used to have to fill every ~2000 miles or so. About 500-700 mpg kinda of light/mix duty. Never see a trailer? You're good to have it done at oil changes.
I usually throw in 2x2.5gallon jugs when I get the 500 mile dash prompt. It sometimes takes a drive cycle for it to pick up on the change. We used to run a lot closer when we were constantly on the highways towing, and fill using the truck stop pumps, but it can strand you if it doesn't pick up on the fact you added DEF fast enough...
I usually throw in 2x2.5gallon jugs when I get the 500 mile dash prompt. It sometimes takes a drive cycle for it to pick up on the change. We used to run a lot closer when we were constantly on the highways towing, and fill using the truck stop pumps, but it can strand you if it doesn't pick up on the fact you added DEF fast enough...
Super Moderator
Joined: Aug 2008
Posts: 37,375
Likes: 1,860
From: Frederick, MD
I would caution excessive filling of the DEF. The system can get even more confused. There are so many warnings that I wait until <200 to empty then do a complete fill.
MInd you I tow heavy and cross country and that is all I do. I carry two 2.5 gal jugs with me and then replace as I use them at my leisure.
MInd you I tow heavy and cross country and that is all I do. I carry two 2.5 gal jugs with me and then replace as I use them at my leisure.
Senior User
Joined: Nov 2017
Posts: 103
Likes: 3
From: Auburn WA
Towing (aggressive) I rip through the DEF. Empty it last forever.
BTW its opposite for the ReGen. Towing the passive regen takes care of most of it, empty it goes to active regen much more frequently.
BTW its opposite for the ReGen. Towing the passive regen takes care of most of it, empty it goes to active regen much more frequently.
More Turbo
Joined: Apr 2017
Posts: 736
Likes: 225
DEF mostly a non-issue, but I am concerned a bit about the DEF purity. There have been stories about yahoos buying DEF from stores, emptying the containers, filling with water, then returning them to the store for a refund, then the store puts it back on the shelf. When I buy, I look for a container that doesn’t have a lot of white residue around the opening, and make sure the seal looks good. Before using I make sure it has a strong ammonia smell, and is a bit sticky to the touch.
Hotshot
Joined: Oct 2015
Posts: 19,682
Likes: 12,804
From: Wyoming
I would caution excessive filling of the DEF. The system can get even more confused. There are so many warnings that I wait until <200 to empty then do a complete fill.
MInd you I tow heavy and cross country and that is all I do. I carry two 2.5 gal jugs with me and then replace as I use them at my leisure.
MInd you I tow heavy and cross country and that is all I do. I carry two 2.5 gal jugs with me and then replace as I use them at my leisure.
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