DEF Math
The owner's manual says my truck has a 5.5 gal DEF tank. I waited until I was down to 1/4 on the gauge, just above the red zone, and added a 2.5 gal box of Blue DEF from Advance Auto. Now the gauge ...
Forum Discussion
rhagfo wrote:Me Again wrote:rhagfo wrote:Cummins12V98 wrote:
15 RAM with gauge at 1/2 a 2.5 fits easily.
X2!
One has to use 1 to 1.5 gallons when the tank is full before the gauge even starts to move down. It is very slow at the top and more speedy on once the gauge starts moving.
While that may be true, at least Ram thought in give you a gauge. Ford and GM didn’t have them early on, and I am not sure if either has a gauge yet.
The 11-16 Super Duty's tells you "The exhaust system is OK", "under half full", and two different miles left warnings (don't remember the exact miles left messages). The '17-Up have a digital DEF gauge.
The Ram def usage rate is not linear and will go down at a faster rate once the fluid gets down to a certain level. Not sure if Ford or GM does the same.
